ordinary soaps in its base, consisting exclusively of potash, in being proportionately richer in alkali, the equivalent of potash being higher than that of soda, and finally, in being perfectly neuter, whilst the soaps prepared with an alkaline ley are generally alkaline. This analysis shews that the soap was prepared with commercial potash; but as carbonate of potash does not saponify suet, and only acts upon fat acids, the latter must have been first made from the fat, which may be done by saponifying the fat with about 12 per cent. of slacked lime. The lime soap thus formed may then be decomposed by means of sulphuric or hydrochloric acids, and the fat acids washed from the lime salt, and perfectly saponified with about 30 per cent. of commercial potash at 90o.- Verhandl. des Nieder-Oest. Gewerbe- Vereins.

Bleaching Lac.-Dr. Hare, of America, has published the following method for bleaching lac:-Dissolve in an iron kettle 1 part of pearl-ash in about 8 parts of water, add 1 part of shell or seed-lac, and heat the whole to ebullition, when the lac is dissolved, cool the solution and impregnate it with chloric gas until the lac is all precipitated. The precipitate is white, but the colour deepens by washing and consolidation; dissolved in alcohol, lac bleached by this process yields a varnish which is as free from colour as any copal varnish. Chloride of lime may be sub stituted for chlorine, chlorine being set free, and the lime being dissolved out of the precipitate by means of some muriatic acid.-Journal of the Smithsonian Insti

tution.

Manufacture of coloured Sealing Wax.-Professor Erdman found on analysing some French coloured sealing waxes of remarkable beauty, among which the pure white and the rose red coloured ones were especially fine, that the colouring material consisted chiefly of basic nitrate of bismuth, (bismuth, pearl or Spanish white,) the rose-red being produced by the addition of carmine. The violet coloured was also produced by a lake and the pearl white. It appears that no other white pigment can be substituted for the bismuth, as no other has an equal body, and is at the same time suitable to form the ground for the organic pigments, with which alone the delicate colours of some fine coloured sealing waxes can be produced. Carbonates like white lead and chalk are not at all suitable, as they froth when melted with the bleached shell-lac, apparently by the resin combining with the base, and driving off the carbonic acid. Magnesia is sometimes prescribed for the preparation of coloured sealing waxes, but zinc white would evidently be better adapted for the preparation of a cheaper though less beautiful product than that which could be made with the bismuth.-Journal für praktische Chemie, Bd. 62, p. 383.

Use of Gutta Percha and Caoutchouc mixed with Oils as Lubricating Agents.— M. Nickels has patented a number of mixtures of fats with gutta percha and caoutchouc for lubricating machinery. His process consists in rolling these materials into thin sheets, which are placed in a quantity of oil sufficient to cover them, and are then heated until they are dissolved, the remainder of the oil and fat being then added, and the whole mixure well stirred.

No. 1.-200 lbs. of palm oil

or No. 2.-200 lbs. of palm oil

The manufacture of Albumen from Blood.-According to Professor Scherer, of Würzburg, the preparation of albumen from blood in Paris, for attaching ultramarine and similar pigments to textile fabrics, consists simply in allowing the blood to flow into tanks under the slaughter-houses, where it is allowed to remain until the clot has separated. The supernatent liquor containing the albumen, in a soluble condition, is then drawn off, and allowed to evaporate spontaneously at

all periods of the year. The product of the evaporation is not pure albumen, but answers as a fixing material for ultramarine. A purer but dearer kind is also made at Paris from the white of egg by evaporation. Immense quantities of blood are annually run into the sewers in Ireland, which might be turned to very good account in this and many other ways. As long, however, as the present system of slaughter-houses scattered through all the lanes in the hearts of our cities and towns is allowed to continue, we cannot hope for the utilization of the blood or any other waste offal, which contributes to pollute the sewers and rivers. -Würzburger Gemeinnützige Wochenschrift, 1854, No. 35, through Polytechnisches Journal, Bd. cxxxiii., Heft. 4.

Action of certain Salts upon Glue.-Hyltén Cavallius has published the results of a great number of experiments upon the behaviour of glue with certain salts, of which we shall notice those of practical importance.

If carbonate of potash, neutral tartrate of potash, carbonate of soda, the double tartrates of potash and soda, sulphate of magnesia, or other salts, be added in the form of powder to a lukewarm solution of glue, made with from four to six times its weight of water, the gelatine will be coagulated, apparently displaced mechanically from the solution by the salt. Dilute solutions of these salts do not precipitate a solution of glue containing common salt. 2. If a warm solution of lime (in six or more times its weight of water,) be saturated with chloride of sodium, chloride of ammonium, chloride of barium, nitrate of potash, bi-chromate of potash, &c., it will not gelatinize on cooling; saturated solutions of these take up, although slowly, dry glue. 3. If a lukewarm, very strong solution of glue, (consisting of 1 part of glue to 3 parts of water,) be treated with a concentrated solution of alum or other alumina salt, the glue will be partially precipitated as a transparent, colourless, stiff mass. A more dilute solution of glue (1 part of glue to 12 of water) becomes very tenacious by the addition of a solution of an alumina salt; if, however, a large quantity be added at once, the action is less marked. A very slight addition of acid, as, for example, acetic acid, prevents all action of alumina salts. Glue behaves in exactly the same way towards persalts of iron, except in the colouring of the precipitate. The precipitates are combinations of glue with alumina and peroxide of iron. If, therefore, a solution of glue saturated with common salt be mixed with alumina or salts of peroxide of iron, about To of the glue will still be precipitated, and if some colouring matter be added to the alum solution a very slight precipitation of glue will be still more easily distinguishable. Glue containing salts of alumina is not very binding, or, as it is expressed, has not much strength; hence the employment of a solution of alum for clearing glue should be avoided. 4. A warm solution of glue does not gelatinize on cooling on the addition of dilute acids, such as hydrochloric, sulphuric, nitric, tartaric, citric, and solution of indigo in sulphuric acid, but if it be now saturated with common salt, colourless or coloured coagulums will be formed. These are most readily formed if the acids named be added to a clear solution of glue, and salt. 5. If glue be dissolved in six times its weight of a strong decoction of certain dye-woods, such as Brazil wood, logwood, &c., then heated, and treated with a solution of bichromate of potash, the whole fluid will solidify into a dark insoluble jelly. If a solution of glue be treated with copperas or sulphate of iron, and then with bi-chromate of potash, it will be precipitated as a brown insoluble mass. If cuttings of glue containing a sufficient quantity of the above mentioned colouring matter or sulphate of iron, be placed in a cold solution of bi-chromate of potash, the glue will be found to remain undissolved. Upon this fact M. Hyltén Cavallius bases a method of quick tanning, a dyeing and mineral tanning. 6. A solution of glue boiled for some minutes with slaked lime loses the property of gelatinizing, and yields, on the evaporation of the water, a gum-like colourless mass, soluble in cold water and in a saturated solution of common salt, the solution in the latter case giving with salts of alumina a precipitate soluble in pure cold water. This gum-like glue when mixed with a proper quantity of pure glue, yields a mixture having the properties of common carpenters' glue, which, when dry, forms an unpliant glassy mass, and becomes moist at certain seasons, and glutinous between the lips, and is partially soluble in cold water. It is well known that such a gum-like substance is produced in

common glue during the long boiling to which it is usually subjected during its preparation, and also partially owing to the action of the caustic lime remaining in the fleshings, &c., used for making the glue, and which is not always removed with sufficient care. Sometimes the glue cannot be brought to gelatinize, which is often attributed to the unfavourable nature of the weather, especially the influence of thunder; but more generally the true cause is the presence of caustic lime, which ought to have been removed or neutralized.-Oefvers. af Vetensk, Akad. Förhandling, 1853, No. 788, p. 166.

Dyeing Bone and Ivory Red.-Killermann has published the following method of dyeing bone, ivory, &c., red. The object is first placed in a bath composed of one-half a litre of soft water, and 13 grammes of nitric acid, and allowed to soak in the cold during 20 to 25 minutes; the bath is then warmed, and the objects again soaked during 10 to 12 minutes. The objects are next removed from the acid bath, and placed in another containing half a litre of water, to which is added, under rapid stirring, a portion of salt of tin about the size of a grain of rice; at the end of 30 minutes the objects are introduced into an almost boiling bath composed of 4.5 grammes each of log-wood and fustic and half a litre of water. When the objects have assumed a clear yellow tint, which occurs at the end of about 5 minutes, at most, they are introduced into the dye bath, which is prepared in the following manner: a little of the finest red carmine is taken upon the point of a knife, and dissolved in from 6 to 8 drops of caustic ammonia, heated gently, or allowed to rest exposed to the air during an hour, a half litre of water added, and the objects to be dyed placed therein, and the whole then boiled; when the objects have become red they are dipped in the acid bath, in which they were first soaked, and then again placed in the dye bath; at the end of a few minutes the operation is terminated, and the objects require merely to be removed from the bath and dried in the air.Oesterreichisches Gewerbeblatt, Heft. 2, p. 53.

Artificial Whalebone.-Under the name of Wallofin, M. Th. Völker, of Meissen, in Saxony, prepares a substitute for whalebone, now gradually becoming dearer, which has all the elasticity of the natural fish bone, at the same time that it is not influenced by moisture, so that rods of it may be steeped for any length of time in water without becoming soft. It may be polished, turned, and bored, and recommends itself especially to umbrella makers by its cheapness.-Deutsche Gewerbezeitung, 1854, Heft. 2, through Polytechnisches Centralblatt, Lief, 16.

Application of essence of Coal as a substitute for Oil of Turpentine.-M. Pelouze, the son of the distinguished chemist of that name, proposes to use an oily fluid consisting of a mixture of carbo-hydrogens, especially of benzine, &c., as a substitute for oil of turpentine in painting. He obtains this fluid, which boils from 100 to 168o centigrade, by the distillation of cannel coal, by means of sur-heated steam. This liquid is colourless, very fluid, and completely volatile, leaving no stain upon paper, and is not altered by exposure to the light. It has a penetrating smell, which reminds one of common coal gas, but this entirely disappears when it has evaporated. A number of comparative experiments have been made, with the object of comparing it with oil of turpentine, by a committee of the Societé d'Encouragement of Paris, all of which have resulted in showing that walls, wood work, &c., painted with paints made with the essence of coal, dried far more rapidly, and the smell disappeared sooner, than where essence of turpentine was employed. For example, in one case where the coal essence and oil of turpentine were respectively mixed with three times their volume of oil, and employed under exactly similar circumstances, the smell of the essence of coal was completely dissipated at the end of three days, while that part painted with the turpentine mixture had still a strong smell, and was not completely dry. The introduction of such an oil would be of great importance, not only in a commercial point of view, but in a hygienic one also.-Bulletin de la Société d' Encouragement, June, 1854, p. 344.

Chemical Arts among the Chinese.-M. Stanislas Julien, the celebrated Orientalist, has announced to the Société d'Encouragement of Paris, that he has collected in one volume, which he is about to publish, the description of the Chinese processes connected with the chemical arts.

all periods of the year. The product of the evaporation is not pure albumen, but answers as a fixing material for ultramarine. A purer but dearer kind is also made at Paris from the white of egg by evaporation. Immense quantities of blood are annually run into the sewers in Ireland, which might be turned to very good account in this and many other ways. As long, however, as the present system of slaughter-houses scattered through all the lanes in the hearts of our cities and towns is allowed to continue, we cannot hope for the utilization of the blood or any other waste offal, which contributes to pollute the sewers and rivers. -Würzburger Gemeinnützige Wochenschrift, 1854, No. 35, through Polytechnisches Journal, Bd. cxxxiii., Heft. 4.

Action of certain Salts upon Glue.-Hyltén Cavallius has published the results of a great number of experiments upon the behaviour of glue with certain salts, of which we shall notice those of practical importance.

If carbonate of potash, neutral tartrate of potash, carbonate of soda, the double tartrates of potash and soda, sulphate of magnesia, or other salts, be added in the form of powder to a lukewarm solution of glue, made with from four to six times its weight of water, the gelatine will be coagulated, apparently displaced mechanically from the solution by the salt. Dilute solutions of these salts do not precipitate a solution of glue containing common salt. 2. If a warm solution of lime (in six or more times its weight of water,) be saturated with chloride of sodium, chloride of ammonium, chloride of barium, nitrate of potash, bi-chromate of potash, &c., it will not gelatinize on cooling; saturated solutions of these take up, although slowly, dry glue. 3. If a lukewarm, very strong solution of glue, (consisting of part of glue to 3 parts of water,) be treated with a concentrated solution of alum or other alumina salt, the glue will be partially precipitated as a transparent, colourless, stiff mass. A more dilute solution of glue (1 part of glue to 12 of water) becomes very tenacious by the addition of a solution of an alumina salt; if, however, a large quantity be added at once, the action is less marked. A very slight addition of acid, as, for example, acetic acid, prevents all action of alumina salts. Glue behaves in exactly the same way towards persalts of iron, except in the colouring of the precipitate. The precipitates are combinations of glue with alumina and peroxide of iron. If, therefore, a solution of glue saturated with common salt be mixed with alumina or salts of peroxide of iron, about of the glue will still be precipitated, and if some colouring matter be added to the alum solution a very slight precipitation of glue will be still more easily distinguishable. Glue containing salts of alumina is not very binding, or, as it is expressed, has not much strength; hence the employment of a solution of alum for clearing glue should be avoided. 4. A warm solution of glue does not gelatinize on cooling on the addition of dilute acids, such as hydrochloric, sulphuric, nitric, tartaric, citric, and solution of indigo in sulphuric acid, but if it be now saturated with common salt, colourless or coloured coagu lums will be formed. These are most readily formed if the acids named be added to a clear solution of glue, and salt. 5. If glue be dissolved in six times its weight of a strong decoction of certain dye-woods, such as Brazil wood, logwood, &c., then heated, and treated with a solution of bichromate of potash, the whole fluid will solidify into a dark insoluble jelly. If a solution of glue be treated with copperas or sulphate of iron, and then with bi-chromate of potash, it will be precipitated as a brown insoluble mass. If cuttings of glue containing a sufficient quantity of the above mentioned colouring matter or sulphate of iron, be placed in a cold solution of bi-chromate of potash, the glue will be found to remain undissolved. Upon this fact M. Hyltén Cavallius bases a method of quick tanning, a dyeing and mineral tanning. 6. A solution of glue boiled for some minutes with slaked lime loses the property of gelatinizing, and yields, on the evaporation of the water, a gum-like colourless mass, soluble in cold water and in a saturated solution of common salt, the solution in the latter case giving with salts of alumina a precipitate soluble in pure cold water. This gum-like glue when mixed with a proper quantity of pure glue, yields a mixture having the properties of common carpenters' glue, which, when dry, forms an unpliant glassy mass, and becomes moist at certain seasons, and glutinous between the lips, and is partially soluble in cold water. It is well known that such a gum-like substance is produced in

common glue during the long boiling to which it is usually subjected during its preparation, and also partially owing to the action of the caustic lime remaining in the fleshings, &c., used for making the glue, and which is not always removed with sufficient care. Sometimes the glue cannot be brought to gelatinize, which is often attributed to the unfavourable nature of the weather, especially the influence of thunder; but more generally the true cause is the presence of caustic lime, which ought to have been removed or neutralized.-Oefvers. af Vetensk, Akad. Förhandling, 1853, No. 788, p. 166.

Dyeing Bone and Ivory Red.—Killermann has published the following method of dyeing bone, ivory, &c., red. The object is first placed in a bath composed of one-half a litre of soft water, and 13 grammes of nitric acid, and allowed to soak in the cold during 20 to 25 minutes; the bath is then warmed, and the objects again soaked during 10 to 12 minutes. The objects are next removed from the acid bath, and placed in another containing half a litre of water, to which is added, under rapid stirring, a portion of salt of tin about the size of a grain of rice; at the end of 30 minutes the objects are introduced into an almost boiling bath composed of 4-5 grammes each of log-wood and fustic and half a litre of water. When the objects have assumed a clear yellow tint, which occurs at the end of about 5 minutes, at most, they are introduced into the dye bath, which is prepared in the following manner: a little of the finest red carmine is taken upon the point of a knife, and dissolved in from 6 to 8 drops of caustic ammonia, heated gently, or allowed to rest exposed to the air during an hour, a half litre of water added, and the objects to be dyed placed therein, and the whole then boiled; when the objects have become red they are dipped in the acid bath, in which they were first soaked, and then again placed in the dye bath; at the end of a few minutes the operation is terminated, and the objects require merely to be removed from the bath and dried in the air.— Oesterreichisches Gewerbeblatt, Heft. 2, p. 53.

Artificial Whalebone.-Under the name of Wallofin, M. Th. Völker, of Meissen, in Saxony, prepares a substitute for whalebone, now gradually becoming dearer, which has all the elasticity of the natural fish bone, at the same time that it is not influenced by moisture, so that rods of it may be steeped for any length of time in water without becoming soft. It may be polished, turned, and bored, and recommends itself especially to umbrella makers by its cheapness.—Deutsche Gewerbezeitung, 1854, Heft. 2, through Polytechnisches Centralblatt, Lief, 16.

Application of essence of Coal as a substitute for Oil of Turpentine.--M. Pelouze, the son of the distinguished chemist of that name, proposes to use an oily fluid consisting of a mixture of carbo-hydrogens, especially of benzine, &c., as a substitute for oil of turpentine in painting. He obtains this fluid, which boils from 100 to 168o centigrade, by the distillation of cannel coal, by means of sur-heated steam. This liquid is colourless, very fluid, and completely volatile, leaving no stain upon paper, and is not altered by exposure to the light. It has a penetrating smell, which reminds one of common coal gas, but this entirely disappears when it has evaporated. A number of comparative experiments have been made, with the object of comparing it with oil of turpentine, by a committee of the Societé d'Encouragement of Paris, all of which have resulted in showing that walls, wood work, &c., painted with paints made with the essence of coal, dried far more rapidly, and the smell disappeared sooner, than where essence of turpentine was employed. For example, in one case where the coal essence and oil of turpentine were respectively mixed with three times their volume of oil, and employed under exactly similar circumstances, the smell of the essence of coal was completely dissipated at the end of three days, while that part painted with the turpentine mixture had still a strong smell, and was not completely dry. The introduction of such an oil would be of great importance, not only in a commercial point of view, but in a hygienic one also.-Bulletin de la Société d'Encouragement, June, 1854, p. 344.

Chemical Arts among the Chinese.-M. Stanislas Julien, the celebrated Orientalist, has announced to the Société d'Encouragement of Paris, that he has collected in one volume, which he is about to publish, the description of the Chinese processes connected with the chemical arts.