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Description of an hermetically-sealed barometer
121
Deserilgtion of an Iarermetical~y-seMed _Barometer.*
By RIClZAItD
AJ)IE, Liverpool. When mounted on an ivory scale, this instrument resembles in size and portability ~ pocket thermometer of the medium or larger class. It is constructed from ~ piece of thermometer tube, in which, in lieu of the spherical or cslil~drical bulb formed for a thermometer, a cistern is made irt the form of the section of a cylinder, 1"4 1) inches diameter and 1-10th of a,l inch thick, varying these 81_ measures according to circumstances ; but generally the bulb has nearly the shape arid dimensions of a half-crown. On the top of the tube there is an air cavity slmih~r to that used a~- -in Dr. Rutherford's registering thermometer. A. T h e cistern c o n t a i n i n g alcohol. lm. T h e tube in which the height corresponding to the barometer is read. c. T h e lop of the alcohol coIumn. 13. T h e air-cavlty for correcting for temperature. 31 to 27. T h e figures to represent the h e i g h t o f the c o l u m n C, with reference to the mercurial col u m n. Sub-dlvisions between each inch are added so as to read oil" to .02.
2~--
--(3
28-- - -
27~ t'~
~'~',
\ )
The influence of change of temperature is got rid of by trial and adjustment of each instrument ; so that the expansion of the air in the upper cavity will counterbalance the expansion of the liquid in the cistern. This correction for temperature applies only to the conditiort of equal heating of the instrument throughout. When it is well done, an instrument is obtained, which is extremely sensitive to any change of atmospherical pressure. If dipped in water at the temperature of the air, the column in th~ tube immediately rises to show the increase of pressure. When carried from one story of a house to another, the change is noticed as the stairs are ascended. In the beginning of last April, I put one of the barometers in the corner of the compartment of the railway carriage in which I was traveling, from Liverpool to Edinburgh, where it indicatcd regularly the extensive changes from the sea level which that line of route contains. The hermetically-sealed barometer which I have found to work best, is filled with colored alcohol ; the colmnn in the tube moving through about 1.5 inches for every inch of the mercurial barometer. :Filled with mercury, instruments corrected for temperature were obtained to move through half an inch for every inch of the barometer ; but, in point of mobility, they were much inferior to alcohol-filled tubes. Filled with ether, an instrument corrected for temperature could not be obtained in combination with delicacy of indication; but if the * From the Lend. Quar. Jour. of the Chemical Society, kpril~ 1860. Vet, XL.--THIRD S ~ l t t : E S . ~ o . 2,~AuGLrST, 1860.
11
:12"2
)lh~ehanies, _Physics, and Chemistry.
correction for temperature be dispensed with, and a place can be found for the barometer where the changes of temperature arc small, ether, in an hermetically-sealed tube of the kind described, wouhl furnish ~ ntost minute, meilsure of changes in atmospheric pressure. A tube tilled with water did not act with delicacy, from the want of mollility in tile ttuid. ]n the hermetically-sealed bar~lmeter, the reading may be much disturbed 1)y un(~qual heating, when the instrument is held in the hand, or the sun allowed to shine on a portion of it. This can in a degree be prevented 1,y the skill of the observer, with the interposition of non-conductors, and when carried by holding the inst~'umcnt suspended bv a cord, rather than keeping it in the pocket or hand. When the (ndication has been disturbed by unequal heating, it must remain suspended fifteen or twenty minutes before a reliable reading can be made.
Thin (5~st L'on. By W~. FAH~m~n~.~,Esq., F. R. S., &c., President, in the Chair. From the Lond. Chemical News, No. 19.
The President exhibited two large pans of cast iron, procured by Mr. Worthington from China, where they arc used for boiling rice. The metal, which is at the strongest part only one-tenth of an inch in thickhess, posscss(~d considerable malleability. The President remarked that the art ,.~fmaking such large castings of thin metal, was unknown
in England.--t~roc. Manchester Lit. and J)hilo. Soc. .Electro CoTies of .Engraved Steel _Plates. :By I t ~ l ~ " B~AD~u~r. From tile Journal of the Society of Arts, No. 389.
Sit( :--Through tile medium of the Journal of the Society of Arts, in July last, I made known the result of my endeavors to deposit pure nickel upon the surface of engraved copper plates. This I have contlnued to do with marked success. The deposit has nearly the appearance of silver in color, possesses almost the hardness of iron, is free from oxidation by air, resists the action of the ordinary acids, and, being easy of manipulation and inexpensive, is well worthy of attention. Each coating will furnish 5000 impressions and upwards. It is so h'trd as to stand the free use of the burnisher, and its texture is so line as not to show the worn away portions of the deposit after each successive coating. Fimling the deposit so beautifully fine in texture and polished in surface, it occurred to me that if an engraved steel plata were covered with such a deposit, the plate might safely be immersed in a solution of sulphate of copper, and a metallic matrix he produced direct from it, without the risk of injury from the action of the acid of the solution. I have tried this with complete success, and have found (as might be sup~.)osed) that an electro copy of a steel plate thus obtained is very supemor to one made from a matrix of gutta percha or other plastic composition. The engraved plate~ however~ must be quite free from under-cut lines. 12 and 13 Fetter Lane~ Yleet Street~ ~ a y 2~ 1860,
Deserilgtion of an Iarermetical~y-seMed _Barometer.*
By RIClZAItD
AJ)IE, Liverpool. When mounted on an ivory scale, this instrument resembles in size and portability ~ pocket thermometer of the medium or larger class. It is constructed from ~ piece of thermometer tube, in which, in lieu of the spherical or cslil~drical bulb formed for a thermometer, a cistern is made irt the form of the section of a cylinder, 1"4 1) inches diameter and 1-10th of a,l inch thick, varying these 81_ measures according to circumstances ; but generally the bulb has nearly the shape arid dimensions of a half-crown. On the top of the tube there is an air cavity slmih~r to that used a~- -in Dr. Rutherford's registering thermometer. A. T h e cistern c o n t a i n i n g alcohol. lm. T h e tube in which the height corresponding to the barometer is read. c. T h e lop of the alcohol coIumn. 13. T h e air-cavlty for correcting for temperature. 31 to 27. T h e figures to represent the h e i g h t o f the c o l u m n C, with reference to the mercurial col u m n. Sub-dlvisions between each inch are added so as to read oil" to .02.
2~--
--(3
28-- - -
27~ t'~
~'~',
\ )
The influence of change of temperature is got rid of by trial and adjustment of each instrument ; so that the expansion of the air in the upper cavity will counterbalance the expansion of the liquid in the cistern. This correction for temperature applies only to the conditiort of equal heating of the instrument throughout. When it is well done, an instrument is obtained, which is extremely sensitive to any change of atmospherical pressure. If dipped in water at the temperature of the air, the column in th~ tube immediately rises to show the increase of pressure. When carried from one story of a house to another, the change is noticed as the stairs are ascended. In the beginning of last April, I put one of the barometers in the corner of the compartment of the railway carriage in which I was traveling, from Liverpool to Edinburgh, where it indicatcd regularly the extensive changes from the sea level which that line of route contains. The hermetically-sealed barometer which I have found to work best, is filled with colored alcohol ; the colmnn in the tube moving through about 1.5 inches for every inch of the mercurial barometer. :Filled with mercury, instruments corrected for temperature were obtained to move through half an inch for every inch of the barometer ; but, in point of mobility, they were much inferior to alcohol-filled tubes. Filled with ether, an instrument corrected for temperature could not be obtained in combination with delicacy of indication; but if the * From the Lend. Quar. Jour. of the Chemical Society, kpril~ 1860. Vet, XL.--THIRD S ~ l t t : E S . ~ o . 2,~AuGLrST, 1860.
11
:12"2
)lh~ehanies, _Physics, and Chemistry.
correction for temperature be dispensed with, and a place can be found for the barometer where the changes of temperature arc small, ether, in an hermetically-sealed tube of the kind described, wouhl furnish ~ ntost minute, meilsure of changes in atmospheric pressure. A tube tilled with water did not act with delicacy, from the want of mollility in tile ttuid. ]n the hermetically-sealed bar~lmeter, the reading may be much disturbed 1)y un(~qual heating, when the instrument is held in the hand, or the sun allowed to shine on a portion of it. This can in a degree be prevented 1,y the skill of the observer, with the interposition of non-conductors, and when carried by holding the inst~'umcnt suspended bv a cord, rather than keeping it in the pocket or hand. When the (ndication has been disturbed by unequal heating, it must remain suspended fifteen or twenty minutes before a reliable reading can be made.
Thin (5~st L'on. By W~. FAH~m~n~.~,Esq., F. R. S., &c., President, in the Chair. From the Lond. Chemical News, No. 19.
The President exhibited two large pans of cast iron, procured by Mr. Worthington from China, where they arc used for boiling rice. The metal, which is at the strongest part only one-tenth of an inch in thickhess, posscss(~d considerable malleability. The President remarked that the art ,.~fmaking such large castings of thin metal, was unknown
in England.--t~roc. Manchester Lit. and J)hilo. Soc. .Electro CoTies of .Engraved Steel _Plates. :By I t ~ l ~ " B~AD~u~r. From tile Journal of the Society of Arts, No. 389.
Sit( :--Through tile medium of the Journal of the Society of Arts, in July last, I made known the result of my endeavors to deposit pure nickel upon the surface of engraved copper plates. This I have contlnued to do with marked success. The deposit has nearly the appearance of silver in color, possesses almost the hardness of iron, is free from oxidation by air, resists the action of the ordinary acids, and, being easy of manipulation and inexpensive, is well worthy of attention. Each coating will furnish 5000 impressions and upwards. It is so h'trd as to stand the free use of the burnisher, and its texture is so line as not to show the worn away portions of the deposit after each successive coating. Fimling the deposit so beautifully fine in texture and polished in surface, it occurred to me that if an engraved steel plata were covered with such a deposit, the plate might safely be immersed in a solution of sulphate of copper, and a metallic matrix he produced direct from it, without the risk of injury from the action of the acid of the solution. I have tried this with complete success, and have found (as might be sup~.)osed) that an electro copy of a steel plate thus obtained is very supemor to one made from a matrix of gutta percha or other plastic composition. The engraved plate~ however~ must be quite free from under-cut lines. 12 and 13 Fetter Lane~ Yleet Street~ ~ a y 2~ 1860,