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Uninflammable stuffs
356
~_feehanles, _Physics, and Chemistry.
The other point to which I have alluded is applicable to the wet mode of separating nickel, and depends upon a fact hitherto, I believe, unnoticed by chemists. If we have in solution a mixture of the sulphotos of nickel, cobalt, zinc, manganese, iron, and copper, we have only to add to this solution in a warm state, as much sulphate of ammonia as it will disolve, and then set it aside to cool. Almos~ every particle of the nickel and cob~dt will separate as a green crystallized powder, and leave the other metals in s,)lution. Tile explanation is very simple. The sulphates of nickel and cobalt for,n triple salts or almns with the sulphate of ammonia, and these salts are absolutely insoluble in a cohl saturated soluti,n of sulphate of ammonia, particularly when this solution is slightly acidulous. [ shall conclmle these remarks upon nickel by stating that this metal appears to possess the property of " w e h l i n g " l i k e i r o n . At my request, a workman heated two small bars of nickel, which h;~(t been previously powdered over with borax, the b~n's were heated in a forge, an, l the two hot ends " j u m p e d " together, that is to say, the white h()t ends were forcibly driven one against the other by gentle blows with a hammer, applied to the other ends, the symmetry of the bar bei~,~ prrserved by blows applied laterally. Although the point of jum.ti()n was afterwards subjected to much twisting, straining, and so t',, th, with a view to test its cohesive power, yet it showed no signs of weakness, even after much cold hammeting. : n i ~ ,~m m , t, le ,S't@ . From the Lend. Mechanics' )lagazine~ March, I863.
On this important suhject the French Academy of Sciences has received a report from MM. Payen, Velpeau, and Rayer, in which M. A. Chevalier's paper, sent in to the Academy on the 251h of January last, is discussed. From this report it appears that only three salts have hitherto been found that may he successfully applied to the purpose in question, viz : tll~t of preventiu;: holies' dresses from catching fire. There are many other salts that would do the same, but not without spoiling the dye, or the gloss, (,r the texture of the stuff', &c. Of the three in question, the sulphate, and phosphate of ammonia have the inconvenience of being decomposed by the heat of a smoothingiron; but they arc applicable in those manufactures where stuffs are stiffened by the actit)n of hot air or cylinders heated by steam. They exercise no action upon either the thread or the eolor of the stuff. The phosphate of ammonia may be mixed with half its weight of hydrochlorate of ammonia. T,) obtain 'm efficacious solution, 20 per cent. of this mixture must De dissolved in water. A solution of 7 per cent. of sulphate of ammonia produces the same effect, and is therefore the most economical salt that the trade can employ. But in those cases in which the smoothing-iron cannot be dispensed with, as in linen, for instance, u s(,lutiuu of 20 per cent. of tungstatc of soda should be preferred. To obtain the. desired effect, all these solutions must be applied to the stuffs after they have been stiffened and. dried, because starch is alwa~':~ used in a weaker solution than that required.
_Proceedings of the British Association.
357
for these salts. Acid tungstates destroy the thread of cotton stuffs, like borax, alum, and other substances previously recommended. The tungstate of soda is prepared in Cornwall, where the tin mines yield a large quantity of wolfram. It costs from £ 1 ° to A~18 per ton, or about 4f. per kilogramme. The sulphate of ammoni;~ costs about ~ 14 per ton ; it is produced in gasworks, and has hitherto been used for
manure.--Galignani. PROCEEDINGS OF THE BRITISH ASSOCIATION. From the London Athena, urn, Oct., 1862.
Section G.--~kleehanical ~'ience. Mr. W. Smith read the Report of the Committee appointed at the las't meeting of the Association to inquire into tile causes of Railway Accidents. This Report was simply provisional, pointing out the steps now in progress for collecting information. Messrs. Williamson of Liverpool, made a communication relative to the merits of Wooden and Iron Ships, with regard to cost of repairs and secm'ity for life, and in the event of' accidents ;~t sea; calling attention in particular, to an iron ship of their own, the Santiago, which met with a collision, the consequences of which wouhl have been absolute destruction of the vessel had she been of wood; whereas, being of iron and having water-tight compartments, the vessel was able to pursue her voyage, and was repaired at the cost of a few hundred pounds, instead of several thousands, which would have been necessary had she been made of wood, and could have been preserved from foundering. Prof. W. J. M. Rankine read a paper "On the Form 'tnd Motion of Waves at and near the Surface of Deep W a t e r s . " - - T h i s paper was a summary of the nature and results of a mathematical investigation, the details of which have been communicated to the Royal Society. The investigations of the Astronomer-Royal and of 5Ir. Stokes on the question of straight-crested parallel waves in a liquid, are based on the supposition that the displacements of the l)-trtieles are small compared with the lengt~h of a wave. They proceed by a method of' approximation, which Mr. Stokes has carried furthest. IIenee it has been very generally inferred that the results of those investigations when applied to waves in which the displacements are eonsideral)le, as compm'ed with the length of wave, are only approximate. In the present paper, the author proves that one of those results,--viz : in very deep water the partieles move with a uniform angular velocity in vertical circles, where radii diminish in geometrical progression with increased depth, and consequently, that surfaces of equal pressure, inelu,ting the upper surface, are trochoidal,--is exact for all possible displacements, how great soever. The author proves further, that the eentres of the orbits of the particles in a given surface of equal pressure stand at a higher level than the same particles do when the liquid is still, by a height which is equal to the height due to the velocity of revolution of the particles; and that, consequently, the mechanical energy of a wave is half actual and half potential (hMf being due to motion and half
~_feehanles, _Physics, and Chemistry.
The other point to which I have alluded is applicable to the wet mode of separating nickel, and depends upon a fact hitherto, I believe, unnoticed by chemists. If we have in solution a mixture of the sulphotos of nickel, cobalt, zinc, manganese, iron, and copper, we have only to add to this solution in a warm state, as much sulphate of ammonia as it will disolve, and then set it aside to cool. Almos~ every particle of the nickel and cob~dt will separate as a green crystallized powder, and leave the other metals in s,)lution. Tile explanation is very simple. The sulphates of nickel and cobalt for,n triple salts or almns with the sulphate of ammonia, and these salts are absolutely insoluble in a cohl saturated soluti,n of sulphate of ammonia, particularly when this solution is slightly acidulous. [ shall conclmle these remarks upon nickel by stating that this metal appears to possess the property of " w e h l i n g " l i k e i r o n . At my request, a workman heated two small bars of nickel, which h;~(t been previously powdered over with borax, the b~n's were heated in a forge, an, l the two hot ends " j u m p e d " together, that is to say, the white h()t ends were forcibly driven one against the other by gentle blows with a hammer, applied to the other ends, the symmetry of the bar bei~,~ prrserved by blows applied laterally. Although the point of jum.ti()n was afterwards subjected to much twisting, straining, and so t',, th, with a view to test its cohesive power, yet it showed no signs of weakness, even after much cold hammeting. : n i ~ ,~m m , t, le ,S't@ . From the Lend. Mechanics' )lagazine~ March, I863.
On this important suhject the French Academy of Sciences has received a report from MM. Payen, Velpeau, and Rayer, in which M. A. Chevalier's paper, sent in to the Academy on the 251h of January last, is discussed. From this report it appears that only three salts have hitherto been found that may he successfully applied to the purpose in question, viz : tll~t of preventiu;: holies' dresses from catching fire. There are many other salts that would do the same, but not without spoiling the dye, or the gloss, (,r the texture of the stuff', &c. Of the three in question, the sulphate, and phosphate of ammonia have the inconvenience of being decomposed by the heat of a smoothingiron; but they arc applicable in those manufactures where stuffs are stiffened by the actit)n of hot air or cylinders heated by steam. They exercise no action upon either the thread or the eolor of the stuff. The phosphate of ammonia may be mixed with half its weight of hydrochlorate of ammonia. T,) obtain 'm efficacious solution, 20 per cent. of this mixture must De dissolved in water. A solution of 7 per cent. of sulphate of ammonia produces the same effect, and is therefore the most economical salt that the trade can employ. But in those cases in which the smoothing-iron cannot be dispensed with, as in linen, for instance, u s(,lutiuu of 20 per cent. of tungstatc of soda should be preferred. To obtain the. desired effect, all these solutions must be applied to the stuffs after they have been stiffened and. dried, because starch is alwa~':~ used in a weaker solution than that required.
_Proceedings of the British Association.
357
for these salts. Acid tungstates destroy the thread of cotton stuffs, like borax, alum, and other substances previously recommended. The tungstate of soda is prepared in Cornwall, where the tin mines yield a large quantity of wolfram. It costs from £ 1 ° to A~18 per ton, or about 4f. per kilogramme. The sulphate of ammoni;~ costs about ~ 14 per ton ; it is produced in gasworks, and has hitherto been used for
manure.--Galignani. PROCEEDINGS OF THE BRITISH ASSOCIATION. From the London Athena, urn, Oct., 1862.
Section G.--~kleehanical ~'ience. Mr. W. Smith read the Report of the Committee appointed at the las't meeting of the Association to inquire into tile causes of Railway Accidents. This Report was simply provisional, pointing out the steps now in progress for collecting information. Messrs. Williamson of Liverpool, made a communication relative to the merits of Wooden and Iron Ships, with regard to cost of repairs and secm'ity for life, and in the event of' accidents ;~t sea; calling attention in particular, to an iron ship of their own, the Santiago, which met with a collision, the consequences of which wouhl have been absolute destruction of the vessel had she been of wood; whereas, being of iron and having water-tight compartments, the vessel was able to pursue her voyage, and was repaired at the cost of a few hundred pounds, instead of several thousands, which would have been necessary had she been made of wood, and could have been preserved from foundering. Prof. W. J. M. Rankine read a paper "On the Form 'tnd Motion of Waves at and near the Surface of Deep W a t e r s . " - - T h i s paper was a summary of the nature and results of a mathematical investigation, the details of which have been communicated to the Royal Society. The investigations of the Astronomer-Royal and of 5Ir. Stokes on the question of straight-crested parallel waves in a liquid, are based on the supposition that the displacements of the l)-trtieles are small compared with the lengt~h of a wave. They proceed by a method of' approximation, which Mr. Stokes has carried furthest. IIenee it has been very generally inferred that the results of those investigations when applied to waves in which the displacements are eonsideral)le, as compm'ed with the length of wave, are only approximate. In the present paper, the author proves that one of those results,--viz : in very deep water the partieles move with a uniform angular velocity in vertical circles, where radii diminish in geometrical progression with increased depth, and consequently, that surfaces of equal pressure, inelu,ting the upper surface, are trochoidal,--is exact for all possible displacements, how great soever. The author proves further, that the eentres of the orbits of the particles in a given surface of equal pressure stand at a higher level than the same particles do when the liquid is still, by a height which is equal to the height due to the velocity of revolution of the particles; and that, consequently, the mechanical energy of a wave is half actual and half potential (hMf being due to motion and half