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New process for tinning iron
New .Processfor Tinnlng Iron.
207
The smallest trace of sulphuretted hydrogen causes a blackening of the liquid, whereas bisulphide of carbon does ndt alter it in the slightest degree. It should be mentioned that if the yellow-red precipitate be allowed to remain under the fluid, it gradually changes color, and becomes white after the lapse of about twenty-four hours. J[f, however, the precipitate be filtered immediately, slightly washed, and dried, it becomes a dark brown. With regard to the explanation of the chemical reactions which occur in this process, the interesting observations made by MM. Zeise and Debus may be quoted as proving that, by the action of sulphide of carbon on ammonia, according to the concentration and temperature of the fluids and the proportion borne by the ammonia to the sulphide, so will the relative amounts of the products of decomposition vary. In concentrated solutions, and when the ammonia is in excess, sulphocarbonate of ammonium and" sulphocyanide of ammonium are formed; in dilute fluids and when sulphide of carbon is in excess, xanthonate of ammonia. Therefore, by this experiment one or other product will preponderate according to circumstances, dependent uport the larger or smaller quantity of sulphide of carbon contained in the gas. In any case, compounds of lead are formed corresponding to the ammonia compounds, which possess at first art orange-red and afterwards a golden-yellow color. :Notwithstanding the complicated nature of the chemical reactions involved in the testing of gas by this process, the author recommends its adoption on account of the practical simplicity which, in his hands, attended the working of a great number of comparative experiments.
NC/~emisclten Centralblatt. l~rew Processfor Tinning Iron. From the London Engineer~ No. 282.
The chief object we have in view in coating iron with tin is to protect it from oxidation, since victuals cooked in untinned iron vessels, far from acquiring any poisonous quality, as they would in copper, would, on the contrary, become more invigorating in proportion to the iron they might absorb ; only their taste would be impaired, and the vessel itself soon become useless. On the other hand, the tincoating is not very durable, and the process of tinning has, therefore, to be often repeated. To obviate this inconvenience, MM. Vivien and Lefebvre have imagined a process for covering iron vessels with a film of nickel before applying the tin. They accordingly begin by scouring the vessels in a mixture of 320 grammes of sulphurie acid and 7 litres of water ; this is done in a wooden cylinder which is made to turn round for about ten minutes ; after which the following substances are added to this bath :--60 grammes of white kitchen-salt, 30 grammes of corrosive sublimate, and 2 grammes of pure sulphate of nickel, and the rotary motion is then continued for about an hour longer. At the end of this time, tile vessels are found to have received a fin% uninterrupted, and very adherent coating of nickel,
208
Mechanics, .P]~ysies, and Chemistry.
which effectually protects the iron from oxidation. They are then put into cold water, and left there while the following second bath is being prepared, viz :--River water, 50 litres ; cream of tartar in powder, 75 deeagrammes; tin in plates, 3 kilogrammes. The whole is made to boil for the space of three hours, after which the iron vessels are put in, and the ebullition is continued for two hours more; by which means the vessels receive a coating of tin deposited on the previous one of nickel. They are then dipped into clean water and rubbed with bran and saw-dust to fit them for use.
Tl~e .Pantelegraph. From the Lond. Mechanics' Magazine, June, 1861.
M. Caselli has succeeded by means of his pantelegraph in conveying, between Paris and Amiens, portraits of the Emperor Napoleon, the Empress Eugenic, the Prince Imperial, also a plan of the :Battle of Moscow, autographs in French, German, Italian, &c. The Morse signals are reproduced perfectly, by means of this invention, at the rate of fifty or sixty words a minute. Two of these pantelegraphs will soon be at work between Paris and Marseilles. M. Caselli proposes to make experiments on a larger scale by establishing pantelegraphs at London, Paris, Marseilles, Florence, and Naples. :By means of this single continuous line, and with only four relays, he proposes to convey between Naples and the other stations named, any document or writing of any kind. 5I. Caselli has already succeeded in establishing, to less than the one-thousandth of • second, the synchronism of two pendulums, one oscillating at Paris, the other at Marseilles, and these synchronisms are independent of the variations in the current of the electric telegraph which joins the two pendulums.
.Decimal Coinage in .Denmarlc. From the Lond. Mechanics' Mag.~ June, 1861.
In the kingdom of Denmark a decimal system of coinage has just been adopted. It comprises four denominations of silver, and one of bronze coins. These are named respectively twenty, ten, five, three, and one cent pieces. The largest coin of the series, which corresponds closely in value with the franc of the French Empire, has for its obverse the well-engraved and massive-looking head of tile king in profile, and surrounded by the legend "Frederick III., Konge Af Danmark," with the date. The reverse represents a ship in full sail over a rippled sea, and bears the inscription, which we leave Danish scholars to translate--" Dansk Vestindisk Mout," with the value of the coin " 2 0 cents," underneath. Tim ship, no doubt, is emblematical of the commerce of the country, and the superiority of its inhabitants as navigators. Tile next coin in point of value, although decorated with the head of the monarch for its obverse, and having the same legends, has a reverse design of quite a different character; namely~ a tall shrub or plant, in flowcr~ which is, of course, indige-
207
The smallest trace of sulphuretted hydrogen causes a blackening of the liquid, whereas bisulphide of carbon does ndt alter it in the slightest degree. It should be mentioned that if the yellow-red precipitate be allowed to remain under the fluid, it gradually changes color, and becomes white after the lapse of about twenty-four hours. J[f, however, the precipitate be filtered immediately, slightly washed, and dried, it becomes a dark brown. With regard to the explanation of the chemical reactions which occur in this process, the interesting observations made by MM. Zeise and Debus may be quoted as proving that, by the action of sulphide of carbon on ammonia, according to the concentration and temperature of the fluids and the proportion borne by the ammonia to the sulphide, so will the relative amounts of the products of decomposition vary. In concentrated solutions, and when the ammonia is in excess, sulphocarbonate of ammonium and" sulphocyanide of ammonium are formed; in dilute fluids and when sulphide of carbon is in excess, xanthonate of ammonia. Therefore, by this experiment one or other product will preponderate according to circumstances, dependent uport the larger or smaller quantity of sulphide of carbon contained in the gas. In any case, compounds of lead are formed corresponding to the ammonia compounds, which possess at first art orange-red and afterwards a golden-yellow color. :Notwithstanding the complicated nature of the chemical reactions involved in the testing of gas by this process, the author recommends its adoption on account of the practical simplicity which, in his hands, attended the working of a great number of comparative experiments.
NC/~emisclten Centralblatt. l~rew Processfor Tinning Iron. From the London Engineer~ No. 282.
The chief object we have in view in coating iron with tin is to protect it from oxidation, since victuals cooked in untinned iron vessels, far from acquiring any poisonous quality, as they would in copper, would, on the contrary, become more invigorating in proportion to the iron they might absorb ; only their taste would be impaired, and the vessel itself soon become useless. On the other hand, the tincoating is not very durable, and the process of tinning has, therefore, to be often repeated. To obviate this inconvenience, MM. Vivien and Lefebvre have imagined a process for covering iron vessels with a film of nickel before applying the tin. They accordingly begin by scouring the vessels in a mixture of 320 grammes of sulphurie acid and 7 litres of water ; this is done in a wooden cylinder which is made to turn round for about ten minutes ; after which the following substances are added to this bath :--60 grammes of white kitchen-salt, 30 grammes of corrosive sublimate, and 2 grammes of pure sulphate of nickel, and the rotary motion is then continued for about an hour longer. At the end of this time, tile vessels are found to have received a fin% uninterrupted, and very adherent coating of nickel,
208
Mechanics, .P]~ysies, and Chemistry.
which effectually protects the iron from oxidation. They are then put into cold water, and left there while the following second bath is being prepared, viz :--River water, 50 litres ; cream of tartar in powder, 75 deeagrammes; tin in plates, 3 kilogrammes. The whole is made to boil for the space of three hours, after which the iron vessels are put in, and the ebullition is continued for two hours more; by which means the vessels receive a coating of tin deposited on the previous one of nickel. They are then dipped into clean water and rubbed with bran and saw-dust to fit them for use.
Tl~e .Pantelegraph. From the Lond. Mechanics' Magazine, June, 1861.
M. Caselli has succeeded by means of his pantelegraph in conveying, between Paris and Amiens, portraits of the Emperor Napoleon, the Empress Eugenic, the Prince Imperial, also a plan of the :Battle of Moscow, autographs in French, German, Italian, &c. The Morse signals are reproduced perfectly, by means of this invention, at the rate of fifty or sixty words a minute. Two of these pantelegraphs will soon be at work between Paris and Marseilles. M. Caselli proposes to make experiments on a larger scale by establishing pantelegraphs at London, Paris, Marseilles, Florence, and Naples. :By means of this single continuous line, and with only four relays, he proposes to convey between Naples and the other stations named, any document or writing of any kind. 5I. Caselli has already succeeded in establishing, to less than the one-thousandth of • second, the synchronism of two pendulums, one oscillating at Paris, the other at Marseilles, and these synchronisms are independent of the variations in the current of the electric telegraph which joins the two pendulums.
.Decimal Coinage in .Denmarlc. From the Lond. Mechanics' Mag.~ June, 1861.
In the kingdom of Denmark a decimal system of coinage has just been adopted. It comprises four denominations of silver, and one of bronze coins. These are named respectively twenty, ten, five, three, and one cent pieces. The largest coin of the series, which corresponds closely in value with the franc of the French Empire, has for its obverse the well-engraved and massive-looking head of tile king in profile, and surrounded by the legend "Frederick III., Konge Af Danmark," with the date. The reverse represents a ship in full sail over a rippled sea, and bears the inscription, which we leave Danish scholars to translate--" Dansk Vestindisk Mout," with the value of the coin " 2 0 cents," underneath. Tim ship, no doubt, is emblematical of the commerce of the country, and the superiority of its inhabitants as navigators. Tile next coin in point of value, although decorated with the head of the monarch for its obverse, and having the same legends, has a reverse design of quite a different character; namely~ a tall shrub or plant, in flowcr~ which is, of course, indige-