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On japanning and varnishing.—No. 7
On Japanning and Varnis/dng.
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at first perfm-mcd. Etruscan vases upon a black ground are remarkably well represented in this way; the vases may afterwards be coloured by using a second stone. Arabesques, vignettes, visidn~ cards, arid numerous other devices may also be produced by the same
process. 'there is another method of proceeding, which is by forming the lines of the drawing, with some deep transparent colour, mixed with gum water. Indian ink answers the purpose extremely well: those called body colours are apt to imbibe the oil which is rubbed upon the stone. When the drawing is quite dry, linseed oil is rubbed upon the stone, and is allowed to remain for seven or eight minutes, that it may be imbibed by those parts which are uncovered, and which is to form the ground. This oil is to be removed fl'om the surface by rubbing it with a piece of soft linen; water is then pom'ed upon the stone, in o,'der to remove all the lines.of the drawing, when it may be prepared by aqua-fortis, and impressions taken from it. This procedure leaves the lines white, upon a ground of black. The same kinds of work may be executed in this way, as by the former, and instead of black, the ground may be of any required colour.
ON J A P A N N I N G A N D V A R N I S H I N G . - - N o .
7.
On makin~ colourless Lac Varnish by two different methods. IN our 4ill volume, p. 150, we published Professor Hate's method of Bleaching Lac, so as to make a colourless varnish. We then stated that tl~e Society, established in London, for the Encourageme~lt of Arts, Manufactures, and Commerce, had continued to offer a premium of a gohl medal, or thirty guineas, ibr the discovery of a process which should accomplish this object. Two applications for the premium have receutly been made to the society; one of them by a gentleman of the name of Field, the other*by a Mr. Luning. '.('he processes of these gel~.flemen differ fi'om each other; and it is stated m the account published by the society, that the method pursued by each of the apt)hcants apl)earin ~ to answer the intended purpose, it has been thought proper to give the reward for both of them.
35"..Fidd's Trocessfor Bleaching Zac. Six ounces of shell-lac, coarsely pounded, are to be dissob'ed by gentle heat in a pint of spirits of Wine. To this is to be added a bleaching liquor, made by dissolving purified carbonate of potash in water, and then impregnatina' it wi{h chlorine a'as, till the silica precipitates, and the solution be~comesslightly col~ured. . Of the above bleaching liquor add one or two ounces to the spiritous solution of lac, and stir the whole well together; effervescence takes place, and when this ceases add more of the bleaching liquor, and thus proceed till the eolour of{he mixture has become pale. .'~. ~econd bleaching liquid is now to be added, made by diluting muriatic
aei( f e d
aci~ the plal Thi liq~ la¢ as 1 ,1 pin the ele~ ..... ; : ' ' :::~ ', Whiteiae varnist~i" says Mr. Field; used in a temperature of not less tl~an sixty dezreesi dries i n a few minutes, and is not atterwards liable to dull or bloom; It !a therefore applicable to drawiugs and prints which have been sized; and may be safely and advanla~eously used upon oil-paintings which have been painted a sutticient ti~ue, as it bears out colour with the purest effect. This quality prevents its obscuring gilding, and render~ it a valuable leather varntsh to the bookbmder, to whose use tt I~as a ready been applied with happy elt'ect, as it does not yield to the warmth of the hand~ and resists damps, which subject bindings to mildew. " A s lac is the basis~ even in name, of all the metallic lackers~ eolourless lae may aftbrd silver and steel lackers~ witli little Orlao Obseuration of their lustre, its varnish polishes better, than any ment:
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Mr. Zuning's process for _Bleaching Lac. Dissolve five ounces of shell-lae in wine~ boil for ~, few minutes with ten cenfly-he~ted animal charcoal, when a shoui~l be drawn oil; and filtered; it" charcoal must be added. When all
a quart of rectified spirit of ounces of well burnt and re5 small quantit 3 of the solutioa not colourtess, a little more colour is removed, press the
~7~
On Japctnning and I~arnishin~,~,
liquor through silk, as linen absorbs more Varnish, and afterwards lter it through fine blotting-paper. In cases where the wax contained in gum laeswould be objection. able, filter cold: if the wax be not injurlous~ filter while hot. On comparing Mr. Luning's varnish with Mr. Field% in the state in which each was sent to the society, the former was of a much thinner consistence, and was rendered ~urbid, by scales of wax and a few particles of charcoal floating in it. On passing it through common white filtering 1)aper, the impurities were separated, and the liquid came throug]~ In a more completely eol0urless state than Mr. Field% This seeming advantage was, however, owing to the much greater state of'dilution of Mr. Luning's varnish; for, when brought " by evaporation to the consistence of Mr. Field's, they each appeared as nearly as possible 9 f the same very pale yellowish tint; so that for the use of the paihter and varnisher they may each be called equally colourless. Mr.;C. Varley having made some interesting comparative experiments oft the two Varnishes~ his letter to the secretary, detailing the same, is here added.
March 31~ 1827. S i r , ' I have varnished some of my sketches with Mr. Field's lac varnish, and some with Mr. Luning's ditto. Mr. Field's varnish appears tO me to answer all that, can he expected from a varnish, i t may b e laid o n as freely ~is any Other varnish, and dries quick, brilliant-an d ;transparent. It is superior " t o all other ~arnishes ill its'approaCh ton glassysurface, and in fi,eedora fq?m tackiness. It is about a right strength or body, though I prefer a sample I had before from Mr. Fiehl, which is as thick aS can be laid on; for it is desirable for a varnish to be as thick as will allow time for it to be spread on, because it then thickens So soon, * that its solvent has no time to act on the oi'l or colours of the picture. Mr. Luning's varnish is a great ~deal. too thin, and the/-efore requires two or three coats before it will bear out; and then, owingto its thinness, the activity of the spirit softens the first coat of varnislb and renders it uneven. It is not so brilliant as Mr. Field's, owing to the mixture (not solution) of wax, and is rather dirty, fi'om the wax retaining some of the charcoal. Therefore I m o s t decidedly give the preference to Mr. Field's varnish. I have succeeded in throwing down both fl~e wax and charcoal by adding spirit (essential oil) of turpentine, wlfiCh dissolves the wax, and the solution then becomes su fiieiently heavy to separate fi'om the varnish; it requires at least one of spirit of turl~entine to three of the varnish beibre the former is heavy 'ehoti~h fO Se'l~aratr, and eheri it is scarcely a liquid, and separates'very slowly; I~aVif more spirit of turpentine is added, it goes d o w n tiUieker. The ,(arnish dissolves a small portion of the spirit of turl~enltin~ WhiCh :I feared might be atll evil, when d ry:ing:,b'ut 1i canno~!p~i~v~?tha~ j:t:!naakes . a,!~'ydiflevering. M r . Luning?s:ya~nj~h;whdi~,i¢~0?f~e,d~!~p~i~!ai,s:moi-ec olour-
N m 13ULL'S Defencc c(' his £xl)eriment~ on FueL
273
~ould be vei'y little dilliwence;, but. probably a union of the two pro~esses may produce the varmsh hke water, though the colour of each is at present equal or superior to most ot the varmshes now 111 USe) and will therefore stand at fl~e head as the chief varnish. I am, sir, &c. A. AIK,~, Esq., Scc. Coaxr:LlUS V~argY. .
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l a the Phih~sophical Transactions, ~ol. I,XXXIV. is a chemical examination of lac by 51r. Ihttchctt, frmu which it appears, that one humlred parts of shell-lac e.nsist of !)[j.!) resin, 4 wax, °~.8 gluten, -rod 0.5 ext,'act. Cohl alcohol will take up eighty-one pa,'ts of the resin, and leave the wax and gluten untouched; it wouhl~ theretbre, lteobably, be an improvetnent on eitht'r of the almve processes, to make the lirst solution of the shell-lac in cohl~ instead of in warm or boiling alcohol. The lirst of tlie tbreg.inyz processes, it will be seen, bears a sl,rong atxah~gy to that of I'vJ}:ss, ' Ihll% ~hich hc iuvciiied some ffeai~; siiicc. 'l'}tt.' I~,t~'W [tl'Otlt'~S iS oltiecii.lmlflc oil ;lt;t¢ltilll. o1 its re.. quh'ing tile lac 1o be re, ice di+~
Notice of M m gUi, l?S ~ Defe)zce of the E:~7)eriments to determine the comparative vah~e of the principal varielies of I"uel~ used i~t the United Stales, ~ 6'c.--Philadelphia, Judah l)obson, Chesnut Street. In the lit'st volume of this Journal, we published the "E.~7~e','L 'menls to determine lhe co~qmralive quanti/ies of Ileal evolved, in the combustion ~f the principal varielies ( f H'ood a)ul Coal, "used "b~ II~e Uidted ,S'lates,Jbr J'uel ; aml, also, to de/crmitze the co~q)m'ative q~,~,~tiUes (f lIeat lost b9 the ordinar.q ~qJparulu.~, "made use ( f ./br their e~mtbastion.~Bff M a R m s Bu~.L.'~ This uiemoir had been read be. lore the Alnerlc~ni Phiioso[,hica[ ~ucicty, slid was immediately pub. lished in their transaciions, ll has .~im-c issued from the press i a ~1,sel)0.Fate l'ol'|ll, altll is thel-eliwc knm~ li (¢~ tm~i :scicntili~; genl.[enl(?m lit pane, 132; of ,mr pl,:,,,cnt ttllt~it~,~ t~il! [a: l;,llml ai~ ac,:~,ailt o[ it
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Ma. 13tmL's Detente oj his E:tTeri'menls o~ level,
premium fi~unded by Count Rumford~ to be given once cw~r), sec~,l~! year " to the author of the most important discovery, ~ u~efifl improvements on heat~ or on ligl% the preference always being gi~,.m to such discoveries as shall tend most to promote the good of mankind ?-" This trust was invested in the American Academy of Arts and Sciences, established in Boston. Although this premium wasl'om~d.. ed thirty years ago, its existence has not become generally known, even to persons engaged in the pursuit ~)f the physical sciences: Mr. Bull, it appears, had been employed in the prosecution of his experiments, during six months, when he accidentally heard or' it, and was advised to prefer his claim as a candidate for its bestowal After completing the intended series of investigations~ and lmbli:~h ina.. them,, as, directed, by_ the Count,. t ds. al)[lication, , was _*,ade to. the. Academy, and referred to a committee. Ihe worl( belore us, Js a pamphlet of about 50 pages, and contains an extended correspondence with this cmnmittee; their report, with remarks the,-eol~ and animad. versions on the manner in which tile trust contidcd to the Academy. has been managed. The objects proposed by Mr. Bull in nndm'taking his expe,'ime, is, placed him, in the most direct manner, in the sitm~tiou of a legitil mate claimant, as this object was to ~'~promote the good of mauki~'i~l.'~ by ascertaining the relative value of articles used as tue/~ and ~hicb are perpetually called for by the necessities and hal)its of civilized man. Tbe only question~ theretbre, to be determined, was, whether' these experiments had been so performed as to accomplish their purpost; the committee, it appears, thought they had not, whilst My. Bull, and a number of his scientitic fi'iends~ entertained a contra~') opinion. In order to attain the highest degree of accuracv of which the experiments were susceptible, Mr. Bull had a room of wood constructed within one of the chambers of his house; within this interior roou:. his experiments on the heat evolved in combustion we,'e per~{'o,'med, whilst the outer room was kept at a temperature of te,a degrees below that of the interior~ in which his essays were made; the iutentio~ of this arrangement was to obviate that uncertainty which woul(i have resulted from any notable change of temperatu,'e~ in the. e,~te~hal atmosphere, during the progress of any experiment. 'l'he corn mittee say, that although the atmosphere of the extel'ior room may be constantly kept at the unit(win ditli~rence of 10 dea,'ees below lhac of the interior, j e t the walls of the two will not rem;~in at tile sam~: difference at their opposite snrfimes, as a reduction of tcmperaluve out of doors~ will cool not only the outer, but also the inner suv[i,'~ of this wall, and thereby cause a greater radiation of heat to it, from the wall of the interior room~ than when the atmosphere ,.emaiued stationary fi-om the beginning. As it was manifestly i~ossib!c to ascertain any appreciable difference in the temperatu~rcof tkese tw,) walls, Mr. Bull proposed to subject the validity of the objection to the test of experiment, contending that if thisditI~rence "was inap preciable~ the objectio,1 must be consklered as invalid; and that although it might be theoretically true, tim practical accuraqy: atnt.
MR. BI;LCs
Dq/i,nce of his Experiments on FueL
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consequent utilit': of his results, wouhl remain nnimpeached. T o the pruposed test the committee demurred, and appeared to consider d~at their decision ou~hi to turn upon tlm theo~:eticaltruth of t h e i r objecii(;n, {xs the,,, do ~ot limit it by ~the extent of an example~' but uf)ov~ (lte l:vutl,, o'fa ,~'~,,',a! "pci,~c;p'lc. Mr. Bull subse{lu{:tltlv asceriahled,l)y a me{hod which appears to us to be vemarkabi~ ac&Hate, that ~vlw,u the difference of the temperature of the rooin/al~d that of the cxhwnal air, was 80% the ditt'erence of the heat (,f the sul-tilcc {}f the wall within the room, aud that of the air in con{act wilh it, was s{} small as not {u affect the most delicate illstrumcnts, oPdiintdl3~ used fop nieasuring tliti~rences of temperatu re. lit wouhl seem tu us, that the reasoning of the cmnnaittee wouhl inevitably lead to the coP,clusiml~ that it is iUllmssible stl to experiment upon the s'uitie{:t ,)I" Mr. Bull's inquiries, as 1{) obiain any information which " shall {elut to pr{mmt{: the ~4()[}{1{}f m a n k i n d / ' and that ~xe must ever r(,a~t:xin 1]~ illler i~lmranc{,} {}1"(he relaiive v;thle of the ditl'erent kind~ {)1 Ii1[,I • :~~ever) eXli{,l'in~{,nt nlu-il, . f nt'cessilv, b{'. l}evformed in l}lac~:s vh(,vi~ ih(.l{: ,v{. vadi:tlin~; sul}.~{ances, and x~;hm'e radiation to :t ~,~ve~lU,v m' Ic:;~ev exIell{, i/liist I)i~ ln!vpetuall.': taking place, hi{lee(t; the {:{)nH}dliee ~{~{utt lo have ih'awll Ibis ctmclusioll themselves, as in r e p l ) i o :l l'Pqllt!st thai they wouhl suggest wllat thev wouhl consider its salisl2t{;ior)~cxpei';illeTit% io deteriuhle the p(iint in dist}ule, they {il)sei've, that lJ,,e2- klioVv o{" I1O experinlents whiell can relnove tilt; dili'<,c:ult)'. A. long conthlued sel'ies of cxpel'hneli{~ and observations made without the precauiions observed by Mr'. Bull, by enll}loying ill I% common room, soum of the ordinar 3 apparatus Ibr the combustion of (uel, tnight:~ ft'om an average estimate (}f their results, furnish i m p e l tent practical inibrniation~ althou°'h the accu,'aev of every individual trial shouhI be fat- inferior to any .one of those obtained by Mr. Bull. I f this be admitted, it wnuhl require a complete inversion of all the ordinary modes of reasoning, to iBfer that experiments made with a minute attention to accuracy~ by removing, as f~tr as possible~ every source nf error, ~ are of no practical value, ~ excepting they bear m every point, the ri~or{)us test of a mathenmticaI demonstration; a t e s t \ v h i e h belongs-not to the science of physics. %Ve have in {he [iJret~ohlg remarks} lnanit~sted our t]~.vourabla opinion of the experiments af Mr. Bull~ and with tile exceptioli of the committee of the Acadenly, we are not acquainted with a single man of science, whose impressions are not shnitar {o our own. T h e exl}eriments have been re-pul}lished in t~;urope, and have been viewed as models for future experinleuters- if we err, lheref{u'e, w{~ have tim sanction of good Cmnl}any; and its lhe opiniol*s e~pressed have n{}t, been formed, without a (Omlietent aequaintznico with the principles involved~ anti a cat'eluI hlvestigalioll of the sul)jecl, lhev must relll;iill unehanged~ until settle, better rea~on~ are tn'~o,d a{rail/st thelll, than any which we have .yet ,~een. The eonehl{lil/~ pai'f of the dei{,Iv?e, it4 dry.fed t(i an inquiry into #/h!' lUalli/er in which the acailelnv ha~ managed the trust connnith~d e}
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)Ino )h ~,r?~ ?),':/',.~.'e
~;/' tti~ l,::~7,e't,i~.~ents o~, ,F:¢cL
lo i[, b.}' (~OI.lllt _Y~.uIl]l'or~i, 'F!lig prenJh~ru~ which was directed to b~: bestowed biemJially~ on ~ the author of the most important disemcry, or useful improveruent~ which shall be made, am! published by printing, or in any way made known to the public," has )lever bee}~ awarded, althou~'h, nearly tifirty years have elapsed, since the time at ~hich it should have bee)) first given; it has in consequence accu.. )mdated, ur~til, instead of a premium of :300, it now amounts to upwards of £000 dollars biennially; a circumstance which tends to defeat the intentions of I:he donor, as it: naturally and neeessarih~ renders the academy averse t,.) its bestowal it~ eases where the smalh~r sum would have been readily awarded. The fi)llowing "ire the coneluding remarks upon this point. " I t was the pI~dn and evident intention of Count Rnrufi)rd, that the premium should be awarded to the author of the ~w:~'limportmd dis.. covery, or useful improvement, on the subject of heat or light: and there can be no doubt, that those subjects are. susceptible of discove,. ties and iruproveruents, of such ,'t nature as was con!eruplated by the donor. Yet the Academy has never awarded the p}'cruium~ and seems to act under the impression daat no discovery or mqwovemcnt of the kind can be made. What then is the plain duty of the A.cadem~? I f its opinion be, that the ~rust tam, at be executed, that opMou ought to be announced in the most public mam~er; that the fund which is in the hands of the h'ustees, may go, where of right it belongs, to the representatives of Count Rumford. I f no such opinim~ as this exists in the Academy, or if the opinion does exist~ and is unsound, the Academy ought to execute the trust. To them is imparted, by the donor, the power of awarding the premium to the most important discovery or useful improvement; and consequently the power, of judging,'; but. this. I)°wer is to be guided by a. •sound discrc.., . ban, and to be exercised under a due sense and a,lust observance of the trust reposed in thcru. These then are questions, which the Academy is bound to answer, ant/ to answer satisfactorilv~how i~ it~ and why is it, that this premium has never been awarded? how is it, and why is it, that this trust is not executcd? how is it, and why is it, that scientific men are invited to di,'ect their eflbrts, prosecute their researches, and exercise their facultie~ on these subjects, mailer a dehMve hope and promise of distinction and reward, which ca)a never be attained ?" _Mr. Bull owed it to bls own reputation, to defend the well earned |,true which his experiments ]tat/ acquired tar him, and we think that he has been eminendy st~ccessftfl in the atterupt; that he l~as ma(le out a thir case, anti shown that the objections urged by the corumittee~ are of that hypothetical chavacter~ which a little ingenuity may raise in every siruilar case,
277 FOR
THE
FRANKLIN
30URNAL.
.Oi,: ~;,.~,,~,q,~,~ ~,~ a t ~'mo~! ~tsed in 8tudn , f o r ~he Preservation, o f
Xhi?~' Bottoms. ('havlc.~ton, $. C., March 10th, 1828. •. rm--.Mttmugh a d,s~ant, s~h,;c,-ibev, I haw~ taken much interes| in tim succes~ ,~f you, ~e,'v ~ah,able Journal, so well calculated to convey u~;elnl inl~n'malim~'amml~ praclical men, like myself. T h e observations by Mr. (;ill, ~ mt various cements,' have brought to lily l't.(O ectiOll ,':I ch'ctlr~ist;t]H~e 'wllich occtJrl'ed sotlle ~.'c'ars ago, l l n d e r
my-~wn obse'vatlon; and I. have thought dmt lhe~publicatiml of it mi'4ht be of w;ry material bem~lit to the. marine dcpartmen% and shipping iui;erest ~d' our clmntry. I am a practical shipwright, and have been constantly en~aged in ,mildin/~11,1 r~.pailin~ v~,;..,.l:-, tl,r tw,.n~)-~d/ht years; in the year ~!~1)4, :;. lar,/o Sl~:mi~h sl,11~, x,.hici~ Vmluired omsiderabh~ rel)air~ av., viw',d ht lhi:pm'l~ ;trot ~;~:, c ~ m m d t t m l l ~ m ) charge. (In lakin~ the •'fld slu'.:tihilv. f~om ihc h~,ilm:~, I fo~md a cL,ai. ~fl p!;~fer, m' chilmm, which atlher~'d %,~ Jirml). ~h:~t. i~ vequh'ed cml~hlcrabh: exevtim~ to dub it t~tt"with tim adzes, l i~ n~)t ~m y adhm'~:d t~,. but appeared to have become ]neorpor~,ted wkl~ ~lm main botlom; its hardness was ahoul, equal to that of soft marble, or l)lasier o[ Paris, in its natural siate. This cement had beet~ mt /lie ship's bottom for many years; and the captain, a~ elderly mau, who was ~l native of Biscay~ ill Spat% requested flint a similar covering should be again applied; on nay cxpressln~," my ignorance of the nature of the preparation, he offeted, with tl{i: assistance of the cook, to make the mixture tbr me, and desired that I would haw'. two plasterers ready, with their trowels, to apply it, when the ship was in a state of readiness to receive it. The composition he made as follows. The best barrelled stone,lime was taken, and slaked, by pouring on it just enough fresh water to produce that effect, and to cause it to fall into a dry white powder: this, when cooled, was sifted through a fine wire sieve, into a tl,ough. like a bread trough; there was then added to it~ a portion of eonimon tlsh oil, sutlicient to bring it to the consistence of soft putty, so as to work with ease under the trowel. No water whatever was used, excepting that fur slaking the lime in the first instance. On the second day of sheathing, the plasterers had put on the width of two or three streaks, all fore and aft, more than we could eover~ and this portion I concluded would wash off in the night, after we had righted the ship. T h e captain laughed at nay fears, and said he would vouch tbr the cement bein~, , there in the niornin~zo ~ . and to. mv.J , no small surprise I fouiM this to be the case. It had acqmred a tinge of'yellow, and was much harder than when put on, although it had been covered with the salt w~ter during the whole night. The captain assured me that it would SOOll attain the hardness of that which had bsen removed. The ship was one oi about 450 tons, amt, as nearly a,~ I can re.collect, the quautit)' of nmteriat used~ ~as about live casks of the
5278 t';srv - ~ / h e Di'u~')-mZ ['lueltt~dion,~" o f lhe /;aro'me[e),o undaked ~fonc-limc, and I lhink, lhr~e ~ixty 5.,;allen cask,~ of (ill, [ sin ilot certain oil this poiut~ alth.ugit ! cannot errgrcatly; fl e consistencc which the mixture must ha,re, will be a snlticient guide tbr the.]l 'op(-imns;.. I is the pv.ccss el making,<, and ap )lying..<.it': lhe n fornlatiol-i v~rlllCh [ IlaV(~ glVelI iS perleetl,v Col'rP.c~. x~_lt}!rIt is prellare d for use, it: is kept ill covered vessels to p r e s e r v e It h'oill the rain~ of other moisture. The shilr's bottom is prepared for sheathing in tile llsual way, by bein~lPaid with a coat of good half stuti; mid allowed to cool, belbre the i~ aster is put on~ as this accelerates its adheshm to tile main bottom. Although it is out of my province, and I am therefore unalfle, to form a judgment on this ll~filit~ [ have thought it worth inquiry whetiler this cheap cement might not be snlJstitutc'd Ibr the costly Roman, or I)utch water i;oilletlts, lit would be \vorth the trial, whether it would not harden il~ fl-esh, as well as in salt water, and answer the purpose of lluihling t.iers, locks, and other structures uMer water. ll'you think these remarks likely to be useful, please to insert them~ and oblige, gours~ &e. ,],t~n~:s ~41MtsiL "
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On the causo~ oJ' the Diurnal l,'luctuation,~ of tD~c l~'aro',neler. TO
TIIE
EDITOIL
OF TIlE
FRANKLIN
JOUI~.NAL,
S1R,--Some years ago I communicated to the American PDilosa irlliieal Society, "l, paper explanatory of the diurn'd fluetua~iolis ot7th,~l/arometer ~As i M t paper liar; ilot appeared ill lheir Iraii~ar.'tiori~ and as no satisl}lctorj explanation of this phenonlenlln has appeared elsewhere, althouah it has bo,eu at~;emlltcd b)- Pro6ssor ]mslie and others~ 1 send re{i the substance orit now for publication, The |Jho,ilom~,lla, as observed by many philosophers, in t1., East and lVest lndies, and ill "%'ario/is parts of the torrid 7,Olle~I.i1"(~the ibllowing:-From (] to 1() ilt tile morning, the bal'ometer rises~ From 10 to 6 in the afternoon, it falls, From 6 to 10 in the evening, it rises, And fronl 10 to 6 ill the morning, it falls. Many years ag% Dr. Balfour instituted, at Calcutta, a nlost latin rlous course of observations on this subject, in which the height of the barometer was noted almost every half hour, fiw one lunation; and the preceding phellomena were observed~ with but two or three sii.ht exceptions, l[uml)ohlt observed nearly the same phenolnem~ iu lltc%Vest Indies. The cause of this fluctuation is so plain, that it is strange it did not occur to either of those+ philosophers. But it; is still IllOl'e sli'allgO that Mr, Imslie, who has doile SO milch for meteorology, should have assigned so inadequate a cause as the sea breeze fiw thi~ phenomenon.
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at first perfm-mcd. Etruscan vases upon a black ground are remarkably well represented in this way; the vases may afterwards be coloured by using a second stone. Arabesques, vignettes, visidn~ cards, arid numerous other devices may also be produced by the same
process. 'there is another method of proceeding, which is by forming the lines of the drawing, with some deep transparent colour, mixed with gum water. Indian ink answers the purpose extremely well: those called body colours are apt to imbibe the oil which is rubbed upon the stone. When the drawing is quite dry, linseed oil is rubbed upon the stone, and is allowed to remain for seven or eight minutes, that it may be imbibed by those parts which are uncovered, and which is to form the ground. This oil is to be removed fl'om the surface by rubbing it with a piece of soft linen; water is then pom'ed upon the stone, in o,'der to remove all the lines.of the drawing, when it may be prepared by aqua-fortis, and impressions taken from it. This procedure leaves the lines white, upon a ground of black. The same kinds of work may be executed in this way, as by the former, and instead of black, the ground may be of any required colour.
ON J A P A N N I N G A N D V A R N I S H I N G . - - N o .
7.
On makin~ colourless Lac Varnish by two different methods. IN our 4ill volume, p. 150, we published Professor Hate's method of Bleaching Lac, so as to make a colourless varnish. We then stated that tl~e Society, established in London, for the Encourageme~lt of Arts, Manufactures, and Commerce, had continued to offer a premium of a gohl medal, or thirty guineas, ibr the discovery of a process which should accomplish this object. Two applications for the premium have receutly been made to the society; one of them by a gentleman of the name of Field, the other*by a Mr. Luning. '.('he processes of these gel~.flemen differ fi'om each other; and it is stated m the account published by the society, that the method pursued by each of the apt)hcants apl)earin ~ to answer the intended purpose, it has been thought proper to give the reward for both of them.
35"..Fidd's Trocessfor Bleaching Zac. Six ounces of shell-lac, coarsely pounded, are to be dissob'ed by gentle heat in a pint of spirits of Wine. To this is to be added a bleaching liquor, made by dissolving purified carbonate of potash in water, and then impregnatina' it wi{h chlorine a'as, till the silica precipitates, and the solution be~comesslightly col~ured. . Of the above bleaching liquor add one or two ounces to the spiritous solution of lac, and stir the whole well together; effervescence takes place, and when this ceases add more of the bleaching liquor, and thus proceed till the eolour of{he mixture has become pale. .'~. ~econd bleaching liquid is now to be added, made by diluting muriatic
aei( f e d
aci~ the plal Thi liq~ la¢ as 1 ,1 pin the ele~ ..... ; : ' ' :::~ ', Whiteiae varnist~i" says Mr. Field; used in a temperature of not less tl~an sixty dezreesi dries i n a few minutes, and is not atterwards liable to dull or bloom; It !a therefore applicable to drawiugs and prints which have been sized; and may be safely and advanla~eously used upon oil-paintings which have been painted a sutticient ti~ue, as it bears out colour with the purest effect. This quality prevents its obscuring gilding, and render~ it a valuable leather varntsh to the bookbmder, to whose use tt I~as a ready been applied with happy elt'ect, as it does not yield to the warmth of the hand~ and resists damps, which subject bindings to mildew. " A s lac is the basis~ even in name, of all the metallic lackers~ eolourless lae may aftbrd silver and steel lackers~ witli little Orlao Obseuration of their lustre, its varnish polishes better, than any ment:
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in white spirit varnishes in generM.
Mr. Zuning's process for _Bleaching Lac. Dissolve five ounces of shell-lae in wine~ boil for ~, few minutes with ten cenfly-he~ted animal charcoal, when a shoui~l be drawn oil; and filtered; it" charcoal must be added. When all
a quart of rectified spirit of ounces of well burnt and re5 small quantit 3 of the solutioa not colourtess, a little more colour is removed, press the
~7~
On Japctnning and I~arnishin~,~,
liquor through silk, as linen absorbs more Varnish, and afterwards lter it through fine blotting-paper. In cases where the wax contained in gum laeswould be objection. able, filter cold: if the wax be not injurlous~ filter while hot. On comparing Mr. Luning's varnish with Mr. Field% in the state in which each was sent to the society, the former was of a much thinner consistence, and was rendered ~urbid, by scales of wax and a few particles of charcoal floating in it. On passing it through common white filtering 1)aper, the impurities were separated, and the liquid came throug]~ In a more completely eol0urless state than Mr. Field% This seeming advantage was, however, owing to the much greater state of'dilution of Mr. Luning's varnish; for, when brought " by evaporation to the consistence of Mr. Field's, they each appeared as nearly as possible 9 f the same very pale yellowish tint; so that for the use of the paihter and varnisher they may each be called equally colourless. Mr.;C. Varley having made some interesting comparative experiments oft the two Varnishes~ his letter to the secretary, detailing the same, is here added.
March 31~ 1827. S i r , ' I have varnished some of my sketches with Mr. Field's lac varnish, and some with Mr. Luning's ditto. Mr. Field's varnish appears tO me to answer all that, can he expected from a varnish, i t may b e laid o n as freely ~is any Other varnish, and dries quick, brilliant-an d ;transparent. It is superior " t o all other ~arnishes ill its'approaCh ton glassysurface, and in fi,eedora fq?m tackiness. It is about a right strength or body, though I prefer a sample I had before from Mr. Fiehl, which is as thick aS can be laid on; for it is desirable for a varnish to be as thick as will allow time for it to be spread on, because it then thickens So soon, * that its solvent has no time to act on the oi'l or colours of the picture. Mr. Luning's varnish is a great ~deal. too thin, and the/-efore requires two or three coats before it will bear out; and then, owingto its thinness, the activity of the spirit softens the first coat of varnislb and renders it uneven. It is not so brilliant as Mr. Field's, owing to the mixture (not solution) of wax, and is rather dirty, fi'om the wax retaining some of the charcoal. Therefore I m o s t decidedly give the preference to Mr. Field's varnish. I have succeeded in throwing down both fl~e wax and charcoal by adding spirit (essential oil) of turpentine, wlfiCh dissolves the wax, and the solution then becomes su fiieiently heavy to separate fi'om the varnish; it requires at least one of spirit of turl~entine to three of the varnish beibre the former is heavy 'ehoti~h fO Se'l~aratr, and eheri it is scarcely a liquid, and separates'very slowly; I~aVif more spirit of turpentine is added, it goes d o w n tiUieker. The ,(arnish dissolves a small portion of the spirit of turl~enltin~ WhiCh :I feared might be atll evil, when d ry:ing:,b'ut 1i canno~!p~i~v~?tha~ j:t:!naakes . a,!~'ydiflevering. M r . Luning?s:ya~nj~h;whdi~,i¢~0?f~e,d~!~p~i~!ai,s:moi-ec olour-
N m 13ULL'S Defencc c(' his £xl)eriment~ on FueL
273
~ould be vei'y little dilliwence;, but. probably a union of the two pro~esses may produce the varmsh hke water, though the colour of each is at present equal or superior to most ot the varmshes now 111 USe) and will therefore stand at fl~e head as the chief varnish. I am, sir, &c. A. AIK,~, Esq., Scc. Coaxr:LlUS V~argY. .
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l a the Phih~sophical Transactions, ~ol. I,XXXIV. is a chemical examination of lac by 51r. Ihttchctt, frmu which it appears, that one humlred parts of shell-lac e.nsist of !)[j.!) resin, 4 wax, °~.8 gluten, -rod 0.5 ext,'act. Cohl alcohol will take up eighty-one pa,'ts of the resin, and leave the wax and gluten untouched; it wouhl~ theretbre, lteobably, be an improvetnent on eitht'r of the almve processes, to make the lirst solution of the shell-lac in cohl~ instead of in warm or boiling alcohol. The lirst of tlie tbreg.inyz processes, it will be seen, bears a sl,rong atxah~gy to that of I'vJ}:ss, ' Ihll% ~hich hc iuvciiied some ffeai~; siiicc. 'l'}tt.' I~,t~'W [tl'Otlt'~S iS oltiecii.lmlflc oil ;lt;t¢ltilll. o1 its re.. quh'ing tile lac 1o be re, ice di+~
Notice of M m gUi, l?S ~ Defe)zce of the E:~7)eriments to determine the comparative vah~e of the principal varielies of I"uel~ used i~t the United Stales, ~ 6'c.--Philadelphia, Judah l)obson, Chesnut Street. In the lit'st volume of this Journal, we published the "E.~7~e','L 'menls to determine lhe co~qmralive quanti/ies of Ileal evolved, in the combustion ~f the principal varielies ( f H'ood a)ul Coal, "used "b~ II~e Uidted ,S'lates,Jbr J'uel ; aml, also, to de/crmitze the co~q)m'ative q~,~,~tiUes (f lIeat lost b9 the ordinar.q ~qJparulu.~, "made use ( f ./br their e~mtbastion.~Bff M a R m s Bu~.L.'~ This uiemoir had been read be. lore the Alnerlc~ni Phiioso[,hica[ ~ucicty, slid was immediately pub. lished in their transaciions, ll has .~im-c issued from the press i a ~1,sel)0.Fate l'ol'|ll, altll is thel-eliwc knm~ li (¢~ tm~i :scicntili~; genl.[enl(?m lit pane, 132; of ,mr pl,:,,,cnt ttllt~it~,~ t~il! [a: l;,llml ai~ ac,:~,ailt o[ it
~74
Ma. 13tmL's Detente oj his E:tTeri'menls o~ level,
premium fi~unded by Count Rumford~ to be given once cw~r), sec~,l~! year " to the author of the most important discovery, ~ u~efifl improvements on heat~ or on ligl% the preference always being gi~,.m to such discoveries as shall tend most to promote the good of mankind ?-" This trust was invested in the American Academy of Arts and Sciences, established in Boston. Although this premium wasl'om~d.. ed thirty years ago, its existence has not become generally known, even to persons engaged in the pursuit ~)f the physical sciences: Mr. Bull, it appears, had been employed in the prosecution of his experiments, during six months, when he accidentally heard or' it, and was advised to prefer his claim as a candidate for its bestowal After completing the intended series of investigations~ and lmbli:~h ina.. them,, as, directed, by_ the Count,. t ds. al)[lication, , was _*,ade to. the. Academy, and referred to a committee. Ihe worl( belore us, Js a pamphlet of about 50 pages, and contains an extended correspondence with this cmnmittee; their report, with remarks the,-eol~ and animad. versions on the manner in which tile trust contidcd to the Academy. has been managed. The objects proposed by Mr. Bull in nndm'taking his expe,'ime, is, placed him, in the most direct manner, in the sitm~tiou of a legitil mate claimant, as this object was to ~'~promote the good of mauki~'i~l.'~ by ascertaining the relative value of articles used as tue/~ and ~hicb are perpetually called for by the necessities and hal)its of civilized man. Tbe only question~ theretbre, to be determined, was, whether' these experiments had been so performed as to accomplish their purpost; the committee, it appears, thought they had not, whilst My. Bull, and a number of his scientitic fi'iends~ entertained a contra~') opinion. In order to attain the highest degree of accuracv of which the experiments were susceptible, Mr. Bull had a room of wood constructed within one of the chambers of his house; within this interior roou:. his experiments on the heat evolved in combustion we,'e per~{'o,'med, whilst the outer room was kept at a temperature of te,a degrees below that of the interior~ in which his essays were made; the iutentio~ of this arrangement was to obviate that uncertainty which woul(i have resulted from any notable change of temperatu,'e~ in the. e,~te~hal atmosphere, during the progress of any experiment. 'l'he corn mittee say, that although the atmosphere of the extel'ior room may be constantly kept at the unit(win ditli~rence of 10 dea,'ees below lhac of the interior, j e t the walls of the two will not rem;~in at tile sam~: difference at their opposite snrfimes, as a reduction of tcmperaluve out of doors~ will cool not only the outer, but also the inner suv[i,'~ of this wall, and thereby cause a greater radiation of heat to it, from the wall of the interior room~ than when the atmosphere ,.emaiued stationary fi-om the beginning. As it was manifestly i~ossib!c to ascertain any appreciable difference in the temperatu~rcof tkese tw,) walls, Mr. Bull proposed to subject the validity of the objection to the test of experiment, contending that if thisditI~rence "was inap preciable~ the objectio,1 must be consklered as invalid; and that although it might be theoretically true, tim practical accuraqy: atnt.
MR. BI;LCs
Dq/i,nce of his Experiments on FueL
275
consequent utilit': of his results, wouhl remain nnimpeached. T o the pruposed test the committee demurred, and appeared to consider d~at their decision ou~hi to turn upon tlm theo~:eticaltruth of t h e i r objecii(;n, {xs the,,, do ~ot limit it by ~the extent of an example~' but uf)ov~ (lte l:vutl,, o'fa ,~'~,,',a! "pci,~c;p'lc. Mr. Bull subse{lu{:tltlv asceriahled,l)y a me{hod which appears to us to be vemarkabi~ ac&Hate, that ~vlw,u the difference of the temperature of the rooin/al~d that of the cxhwnal air, was 80% the ditt'erence of the heat (,f the sul-tilcc {}f the wall within the room, aud that of the air in con{act wilh it, was s{} small as not {u affect the most delicate illstrumcnts, oPdiintdl3~ used fop nieasuring tliti~rences of temperatu re. lit wouhl seem tu us, that the reasoning of the cmnnaittee wouhl inevitably lead to the coP,clusiml~ that it is iUllmssible stl to experiment upon the s'uitie{:t ,)I" Mr. Bull's inquiries, as 1{) obiain any information which " shall {elut to pr{mmt{: the ~4()[}{1{}f m a n k i n d / ' and that ~xe must ever r(,a~t:xin 1]~ illler i~lmranc{,} {}1"(he relaiive v;thle of the ditl'erent kind~ {)1 Ii1[,I • :~~ever) eXli{,l'in~{,nt nlu-il, . f nt'cessilv, b{'. l}evformed in l}lac~:s vh(,vi~ ih(.l{: ,v{. vadi:tlin~; sul}.~{ances, and x~;hm'e radiation to :t ~,~ve~lU,v m' Ic:;~ev exIell{, i/liist I)i~ ln!vpetuall.': taking place, hi{lee(t; the {:{)nH}dliee ~{~{utt lo have ih'awll Ibis ctmclusioll themselves, as in r e p l ) i o :l l'Pqllt!st thai they wouhl suggest wllat thev wouhl consider its salisl2t{;ior)~cxpei';illeTit% io deteriuhle the p(iint in dist}ule, they {il)sei've, that lJ,,e2- klioVv o{" I1O experinlents whiell can relnove tilt; dili'<,c:ult)'. A. long conthlued sel'ies of cxpel'hneli{~ and observations made without the precauiions observed by Mr'. Bull, by enll}loying ill I% common room, soum of the ordinar 3 apparatus Ibr the combustion of (uel, tnight:~ ft'om an average estimate (}f their results, furnish i m p e l tent practical inibrniation~ althou°'h the accu,'aev of every individual trial shouhI be fat- inferior to any .one of those obtained by Mr. Bull. I f this be admitted, it wnuhl require a complete inversion of all the ordinary modes of reasoning, to iBfer that experiments made with a minute attention to accuracy~ by removing, as f~tr as possible~ every source nf error, ~ are of no practical value, ~ excepting they bear m every point, the ri~or{)us test of a mathenmticaI demonstration; a t e s t \ v h i e h belongs-not to the science of physics. %Ve have in {he [iJret~ohlg remarks} lnanit~sted our t]~.vourabla opinion of the experiments af Mr. Bull~ and with tile exceptioli of the committee of the Acadenly, we are not acquainted with a single man of science, whose impressions are not shnitar {o our own. T h e exl}eriments have been re-pul}lished in t~;urope, and have been viewed as models for future experinleuters- if we err, lheref{u'e, w{~ have tim sanction of good Cmnl}any; and its lhe opiniol*s e~pressed have n{}t, been formed, without a (Omlietent aequaintznico with the principles involved~ anti a cat'eluI hlvestigalioll of the sul)jecl, lhev must relll;iill unehanged~ until settle, better rea~on~ are tn'~o,d a{rail/st thelll, than any which we have .yet ,~een. The eonehl{lil/~ pai'f of the dei{,Iv?e, it4 dry.fed t(i an inquiry into #/h!' lUalli/er in which the acailelnv ha~ managed the trust connnith~d e}
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)Ino )h ~,r?~ ?),':/',.~.'e
~;/' tti~ l,::~7,e't,i~.~ents o~, ,F:¢cL
lo i[, b.}' (~OI.lllt _Y~.uIl]l'or~i, 'F!lig prenJh~ru~ which was directed to b~: bestowed biemJially~ on ~ the author of the most important disemcry, or useful improveruent~ which shall be made, am! published by printing, or in any way made known to the public," has )lever bee}~ awarded, althou~'h, nearly tifirty years have elapsed, since the time at ~hich it should have bee)) first given; it has in consequence accu.. )mdated, ur~til, instead of a premium of :300, it now amounts to upwards of £000 dollars biennially; a circumstance which tends to defeat the intentions of I:he donor, as it: naturally and neeessarih~ renders the academy averse t,.) its bestowal it~ eases where the smalh~r sum would have been readily awarded. The fi)llowing "ire the coneluding remarks upon this point. " I t was the pI~dn and evident intention of Count Rnrufi)rd, that the premium should be awarded to the author of the ~w:~'limportmd dis.. covery, or useful improvement, on the subject of heat or light: and there can be no doubt, that those subjects are. susceptible of discove,. ties and iruproveruents, of such ,'t nature as was con!eruplated by the donor. Yet the Academy has never awarded the p}'cruium~ and seems to act under the impression daat no discovery or mqwovemcnt of the kind can be made. What then is the plain duty of the A.cadem~? I f its opinion be, that the ~rust tam, at be executed, that opMou ought to be announced in the most public mam~er; that the fund which is in the hands of the h'ustees, may go, where of right it belongs, to the representatives of Count Rumford. I f no such opinim~ as this exists in the Academy, or if the opinion does exist~ and is unsound, the Academy ought to execute the trust. To them is imparted, by the donor, the power of awarding the premium to the most important discovery or useful improvement; and consequently the power, of judging,'; but. this. I)°wer is to be guided by a. •sound discrc.., . ban, and to be exercised under a due sense and a,lust observance of the trust reposed in thcru. These then are questions, which the Academy is bound to answer, ant/ to answer satisfactorilv~how i~ it~ and why is it, that this premium has never been awarded? how is it, and why is it, that this trust is not executcd? how is it, and why is it, that scientific men are invited to di,'ect their eflbrts, prosecute their researches, and exercise their facultie~ on these subjects, mailer a dehMve hope and promise of distinction and reward, which ca)a never be attained ?" _Mr. Bull owed it to bls own reputation, to defend the well earned |,true which his experiments ]tat/ acquired tar him, and we think that he has been eminendy st~ccessftfl in the atterupt; that he l~as ma(le out a thir case, anti shown that the objections urged by the corumittee~ are of that hypothetical chavacter~ which a little ingenuity may raise in every siruilar case,
277 FOR
THE
FRANKLIN
30URNAL.
.Oi,: ~;,.~,,~,q,~,~ ~,~ a t ~'mo~! ~tsed in 8tudn , f o r ~he Preservation, o f
Xhi?~' Bottoms. ('havlc.~ton, $. C., March 10th, 1828. •. rm--.Mttmugh a d,s~ant, s~h,;c,-ibev, I haw~ taken much interes| in tim succes~ ,~f you, ~e,'v ~ah,able Journal, so well calculated to convey u~;elnl inl~n'malim~'amml~ praclical men, like myself. T h e observations by Mr. (;ill, ~ mt various cements,' have brought to lily l't.(O ectiOll ,':I ch'ctlr~ist;t]H~e 'wllich occtJrl'ed sotlle ~.'c'ars ago, l l n d e r
my-~wn obse'vatlon; and I. have thought dmt lhe~publicatiml of it mi'4ht be of w;ry material bem~lit to the. marine dcpartmen% and shipping iui;erest ~d' our clmntry. I am a practical shipwright, and have been constantly en~aged in ,mildin/~11,1 r~.pailin~ v~,;..,.l:-, tl,r tw,.n~)-~d/ht years; in the year ~!~1)4, :;. lar,/o Sl~:mi~h sl,11~, x,.hici~ Vmluired omsiderabh~ rel)air~ av., viw',d ht lhi:pm'l~ ;trot ~;~:, c ~ m m d t t m l l ~ m ) charge. (In lakin~ the •'fld slu'.:tihilv. f~om ihc h~,ilm:~, I fo~md a cL,ai. ~fl p!;~fer, m' chilmm, which atlher~'d %,~ Jirml). ~h:~t. i~ vequh'ed cml~hlcrabh: exevtim~ to dub it t~tt"with tim adzes, l i~ n~)t ~m y adhm'~:d t~,. but appeared to have become ]neorpor~,ted wkl~ ~lm main botlom; its hardness was ahoul, equal to that of soft marble, or l)lasier o[ Paris, in its natural siate. This cement had beet~ mt /lie ship's bottom for many years; and the captain, a~ elderly mau, who was ~l native of Biscay~ ill Spat% requested flint a similar covering should be again applied; on nay cxpressln~," my ignorance of the nature of the preparation, he offeted, with tl{i: assistance of the cook, to make the mixture tbr me, and desired that I would haw'. two plasterers ready, with their trowels, to apply it, when the ship was in a state of readiness to receive it. The composition he made as follows. The best barrelled stone,lime was taken, and slaked, by pouring on it just enough fresh water to produce that effect, and to cause it to fall into a dry white powder: this, when cooled, was sifted through a fine wire sieve, into a tl,ough. like a bread trough; there was then added to it~ a portion of eonimon tlsh oil, sutlicient to bring it to the consistence of soft putty, so as to work with ease under the trowel. No water whatever was used, excepting that fur slaking the lime in the first instance. On the second day of sheathing, the plasterers had put on the width of two or three streaks, all fore and aft, more than we could eover~ and this portion I concluded would wash off in the night, after we had righted the ship. T h e captain laughed at nay fears, and said he would vouch tbr the cement bein~, , there in the niornin~zo ~ . and to. mv.J , no small surprise I fouiM this to be the case. It had acqmred a tinge of'yellow, and was much harder than when put on, although it had been covered with the salt w~ter during the whole night. The captain assured me that it would SOOll attain the hardness of that which had bsen removed. The ship was one oi about 450 tons, amt, as nearly a,~ I can re.collect, the quautit)' of nmteriat used~ ~as about live casks of the
5278 t';srv - ~ / h e Di'u~')-mZ ['lueltt~dion,~" o f lhe /;aro'me[e),o undaked ~fonc-limc, and I lhink, lhr~e ~ixty 5.,;allen cask,~ of (ill, [ sin ilot certain oil this poiut~ alth.ugit ! cannot errgrcatly; fl e consistencc which the mixture must ha,re, will be a snlticient guide tbr the.]l 'op(-imns;.. I is the pv.ccss el making,<, and ap )lying..<.it': lhe n fornlatiol-i v~rlllCh [ IlaV(~ glVelI iS perleetl,v Col'rP.c~. x~_lt}!rIt is prellare d for use, it: is kept ill covered vessels to p r e s e r v e It h'oill the rain~ of other moisture. The shilr's bottom is prepared for sheathing in tile llsual way, by bein~lPaid with a coat of good half stuti; mid allowed to cool, belbre the i~ aster is put on~ as this accelerates its adheshm to tile main bottom. Although it is out of my province, and I am therefore unalfle, to form a judgment on this ll~filit~ [ have thought it worth inquiry whetiler this cheap cement might not be snlJstitutc'd Ibr the costly Roman, or I)utch water i;oilletlts, lit would be \vorth the trial, whether it would not harden il~ fl-esh, as well as in salt water, and answer the purpose of lluihling t.iers, locks, and other structures uMer water. ll'you think these remarks likely to be useful, please to insert them~ and oblige, gours~ &e. ,],t~n~:s ~41MtsiL "
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On the causo~ oJ' the Diurnal l,'luctuation,~ of tD~c l~'aro',neler. TO
TIIE
EDITOIL
OF TIlE
FRANKLIN
JOUI~.NAL,
S1R,--Some years ago I communicated to the American PDilosa irlliieal Society, "l, paper explanatory of the diurn'd fluetua~iolis ot7th,~l/arometer ~As i M t paper liar; ilot appeared ill lheir Iraii~ar.'tiori~ and as no satisl}lctorj explanation of this phenonlenlln has appeared elsewhere, althouah it has bo,eu at~;emlltcd b)- Pro6ssor ]mslie and others~ 1 send re{i the substance orit now for publication, The |Jho,ilom~,lla, as observed by many philosophers, in t1., East and lVest lndies, and ill "%'ario/is parts of the torrid 7,Olle~I.i1"(~the ibllowing:-From (] to 1() ilt tile morning, the bal'ometer rises~ From 10 to 6 in the afternoon, it falls, From 6 to 10 in the evening, it rises, And fronl 10 to 6 ill the morning, it falls. Many years ag% Dr. Balfour instituted, at Calcutta, a nlost latin rlous course of observations on this subject, in which the height of the barometer was noted almost every half hour, fiw one lunation; and the preceding phellomena were observed~ with but two or three sii.ht exceptions, l[uml)ohlt observed nearly the same phenolnem~ iu lltc%Vest Indies. The cause of this fluctuation is so plain, that it is strange it did not occur to either of those+ philosophers. But it; is still IllOl'e sli'allgO that Mr, Imslie, who has doile SO milch for meteorology, should have assigned so inadequate a cause as the sea breeze fiw thi~ phenomenon.