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Artificial stone
eomplish the end in view so well as the other sllbsranees. The quantity of oxygen liberated is smaller, an(t permanganic acid is formed.
2)alton's T]~er~oraete~'. l~rom tim L(~n(l~n Chemir!~d News, N(~. 279.
At a recent meeting of the 5Ianchester Literary and Philosophical Society, Mr. Baxendell stated theft the Society had in its possession a thermometer, constructed by the ]ate Dr. Dalton, ~,nd which, it is believed, was used by him in many of his meteorological observations. The scale had the initials " J. D." and the year " 1823 " engraved upon it ; and the freezing and boiling points of water are indicated on the stem by fine file marks. As it is known that the zero points of thermometers sometimes change to the extent of one or even two degrees in the course of several years, it occurred to Sir. Baxendell that it would be interesting to ascertain whether any change had taken place in this thermometer, and he had, therefore, lately tested very carefully the position of the freezing point, but found that no sensible alteration had taken place; and he believed, therefore, that great confidence might be placed in the observations which Dalton had made with this instrument.
Artificial Stone. From the London Mechanics' Mag~zil~e, September, 1865.
To obtain a factitious stone which may take the place of the ordinary Turkey, Water of Ayre, and Arkansas stones used for sharpening cutting tools, and for kindred purposes, is the object of an invention recently patented by Mr. E. Parnacott, of Leeds. To this end he prepares a compound which will admit of being moulded to any required form, and which, when moulded may be hardened and brought to the consistency of stone. In carrying out the improved manufacture, the chips ahd dust obtained in preparing lithographic stones are reduced to fine granules, emery powder, borax, and saltpetre are added, and the whole thoroughly inixed in a mill. The mixture thus obtained is movlded to any required shape--for example, cutting and polishing tools ; the same is first submitted to hydraulic pressure, and then to furnace heat, whereby the hardness and consistency of stone is imparted to the moulded articles. The following proportions will produce good result, viz : pounded lithographic stone twelve ounces, borax two ounces, saltpetre half an ounce, and very fine emery two ounces. Place these substances together in an ordinary incorporating mill with edge runners, (such as is used for preparing mastic and sand,) the pan of" the mill being heated by steam or gas, and subject the substances to the action of the mill until they are well mixed and incorporated. Then remove the compound thus formed and place it in strong iron mouhts for the purpose of being submitted to pressure. These moulds are made of various shapes to suit the purposes for which the artificial stone is to be used.
46
2][ecltanlcs, Pltysies, and Chemistry.
The pressure necessary to effect a proper consolldation of the compound may be conveniently given by means of a strong hydraulic press. The amount of pressure which has proved satisfactory is about twenty tons per square inch of surface of the moulded article. When the requisite mechanic~d consolidation of the moulded article has beenthus obtained, the moulded article is subjected to a white heat in any suitable construction of furnace, or to such a heat as will serve to fuse the borax and saltpetre, and effect the binding together of the granules of stone and emery. The time required for attaining this object will in general be from half an hour to one hour. To prevent the warping and running of the mouhled compound under heat, it is clamped in moulds made of plumbago, fire-clay, or other like heat-resisting material, before being placed in the furnace. When it is required to produce cutting or polishing wheels, hones, or other like articles with a less cutting power than those made from the before-named mixture, ordinary chalk is substituted for a portion of the lithographic stone granules. The proportions of the chalk and the granules should be half of each to produce a good resu].t, the proportions of the other materials being retained.
On the .Effect o5 Blowing Blast Furnaces with Blast of very ttigh Temperature. :By Mr. E. A. COWPEa. :From the London Artizan, .November, 1865.
It is not proposed to detain the meeting with a history of the numerous attempts which have been made to raise the blast furnaces to a very high tetn'perature, nor will the author occupy much time in the description of the means by which the desired result has been obtained, as a full account of the apparatus was given at tile meeting of this Association held at Oxford, (though the paper on the subject was not printed in the Transactions.) In 1861, experimental stoves only on the new plan had been erected, and worked f o r heating the blast for one tuyere, out of the five used for one blast furnace. Such satisfac tory results were however obtained, that it was clear that the difficulty of procuring blast of very high temperature had been overcome, and }Jessrs. Cochrane & Co., of Woodside Iron Works, Dudley, and Ormesley :Iron Works, near Middlesbro'-on-Tees, forthwith erected largo stoves on the new plan for a complete blast furnace ; and it is now proposed, with your permission, to lay before the section the results obtained during upwards of six years practical working with these stoves. The effect of heating air on the new plan was that a temperature of blast of 1150 ° :Fahr. was obtained, instead of only 600 or 700 °, as ~vith cast iron pipes in the common stoves. There was no loss of blast from leakage, owing to the cracked or damaged cast iron pipes; the iron produced was of rather better quality ; 20 per cent. more iron was made from the same furnace; and fully 5 cwt. of coke was saved in the blast furnace per ton of iron made. The details of the constru0tion of the new stoves ~vill be easily understood.
2)alton's T]~er~oraete~'. l~rom tim L(~n(l~n Chemir!~d News, N(~. 279.
At a recent meeting of the 5Ianchester Literary and Philosophical Society, Mr. Baxendell stated theft the Society had in its possession a thermometer, constructed by the ]ate Dr. Dalton, ~,nd which, it is believed, was used by him in many of his meteorological observations. The scale had the initials " J. D." and the year " 1823 " engraved upon it ; and the freezing and boiling points of water are indicated on the stem by fine file marks. As it is known that the zero points of thermometers sometimes change to the extent of one or even two degrees in the course of several years, it occurred to Sir. Baxendell that it would be interesting to ascertain whether any change had taken place in this thermometer, and he had, therefore, lately tested very carefully the position of the freezing point, but found that no sensible alteration had taken place; and he believed, therefore, that great confidence might be placed in the observations which Dalton had made with this instrument.
Artificial Stone. From the London Mechanics' Mag~zil~e, September, 1865.
To obtain a factitious stone which may take the place of the ordinary Turkey, Water of Ayre, and Arkansas stones used for sharpening cutting tools, and for kindred purposes, is the object of an invention recently patented by Mr. E. Parnacott, of Leeds. To this end he prepares a compound which will admit of being moulded to any required form, and which, when moulded may be hardened and brought to the consistency of stone. In carrying out the improved manufacture, the chips ahd dust obtained in preparing lithographic stones are reduced to fine granules, emery powder, borax, and saltpetre are added, and the whole thoroughly inixed in a mill. The mixture thus obtained is movlded to any required shape--for example, cutting and polishing tools ; the same is first submitted to hydraulic pressure, and then to furnace heat, whereby the hardness and consistency of stone is imparted to the moulded articles. The following proportions will produce good result, viz : pounded lithographic stone twelve ounces, borax two ounces, saltpetre half an ounce, and very fine emery two ounces. Place these substances together in an ordinary incorporating mill with edge runners, (such as is used for preparing mastic and sand,) the pan of" the mill being heated by steam or gas, and subject the substances to the action of the mill until they are well mixed and incorporated. Then remove the compound thus formed and place it in strong iron mouhts for the purpose of being submitted to pressure. These moulds are made of various shapes to suit the purposes for which the artificial stone is to be used.
46
2][ecltanlcs, Pltysies, and Chemistry.
The pressure necessary to effect a proper consolldation of the compound may be conveniently given by means of a strong hydraulic press. The amount of pressure which has proved satisfactory is about twenty tons per square inch of surface of the moulded article. When the requisite mechanic~d consolidation of the moulded article has beenthus obtained, the moulded article is subjected to a white heat in any suitable construction of furnace, or to such a heat as will serve to fuse the borax and saltpetre, and effect the binding together of the granules of stone and emery. The time required for attaining this object will in general be from half an hour to one hour. To prevent the warping and running of the mouhled compound under heat, it is clamped in moulds made of plumbago, fire-clay, or other like heat-resisting material, before being placed in the furnace. When it is required to produce cutting or polishing wheels, hones, or other like articles with a less cutting power than those made from the before-named mixture, ordinary chalk is substituted for a portion of the lithographic stone granules. The proportions of the chalk and the granules should be half of each to produce a good resu].t, the proportions of the other materials being retained.
On the .Effect o5 Blowing Blast Furnaces with Blast of very ttigh Temperature. :By Mr. E. A. COWPEa. :From the London Artizan, .November, 1865.
It is not proposed to detain the meeting with a history of the numerous attempts which have been made to raise the blast furnaces to a very high tetn'perature, nor will the author occupy much time in the description of the means by which the desired result has been obtained, as a full account of the apparatus was given at tile meeting of this Association held at Oxford, (though the paper on the subject was not printed in the Transactions.) In 1861, experimental stoves only on the new plan had been erected, and worked f o r heating the blast for one tuyere, out of the five used for one blast furnace. Such satisfac tory results were however obtained, that it was clear that the difficulty of procuring blast of very high temperature had been overcome, and }Jessrs. Cochrane & Co., of Woodside Iron Works, Dudley, and Ormesley :Iron Works, near Middlesbro'-on-Tees, forthwith erected largo stoves on the new plan for a complete blast furnace ; and it is now proposed, with your permission, to lay before the section the results obtained during upwards of six years practical working with these stoves. The effect of heating air on the new plan was that a temperature of blast of 1150 ° :Fahr. was obtained, instead of only 600 or 700 °, as ~vith cast iron pipes in the common stoves. There was no loss of blast from leakage, owing to the cracked or damaged cast iron pipes; the iron produced was of rather better quality ; 20 per cent. more iron was made from the same furnace; and fully 5 cwt. of coke was saved in the blast furnace per ton of iron made. The details of the constru0tion of the new stoves ~vill be easily understood.