formed in different ways, but the following is the process which at present appears to me the best, and which I employ.

The farina, flour, or starch, being in a dry state, a portion of nitric acid of the specific gravity of about 1.4, equal in weight to one 400th part of the farina or flour, is mixed with such a quantity of pure water as is sufficient to wet the farina, flour, or starch, which is then carefully mixed with this fluid, so that every part of it may be wetted much as bread is mixed or kneaded.

It is not however necessary (though I think preferable) that the farina or flour of potatoes and similar substances, should be brought into a dry state, but it may be used as it is obtained by the maker from the tub or vat. In such case, a less portion of water will be required in the admixture of the nitric acid.

The paste thus formed is divided into lumps of any convenient size, say about twenty-five pounds weight, and these should be put to drain for a few hours, to allow any superfluous moisture to run off. The lumps should then be broken with the hands into small pieces, and placed in a chamber heated to any degree not exceeding 176 degrees of Fahrenheit, and kept there till perfectly dry (which at the heat of 176 degrees will be done within twenty hours), and they are then reduced to the state of flour, by pounding or grinding, and the use of a bolter or sieve; and this flour is then placed in an oven heated to from 212 to 248 degrees Fahrenheit, where it is kept till thoroughly dry. The time necessary for this purpose will vary according to the degree of heat, from about a quarter of an hour to five minutes: the lower the degree of heat within the prescribed limits, the dextrine will be the whiter, which is advantageous.

When wanted to be used for any of the purposes which I shall presently describe, the dextrine thus obtained is to be mixed with water, either cold or hot. The proportion of water varies according to the consistence of the liquor required, which differs for different purposes. The product is a gummy or gum like liquor, similar to the solution of gum-senegal in water, and its principal uses are as a substitute for that gum.

The most general object for which the dextrine is used, is a substitute for the solution of gum-senegal and other gummy or gum like substances, in printing and dressing silk, cotton, linen, and other fabrics; in painting or printing paper-hangings, in all sorts of distemper painting, in stiffening the different fabrics which require it, such as gauze, and in all the preparations which required formerly the use of starch and calcined starch, calcined farina, or British gum; also in the preparation of adhesive plaisters and bandages for surgical purposes, in glazing visiting cards and other papers: in short, it is a perfect substitute for gum-senegal and other gummy and gumlike substances, in all processes of this nature with which I am acquainted, while it is much cheaper than any of them.

Any heated chamber and any oven in which heat can be obtained at the degrees mentioned above, will answer the above purposes.

I wish to observe, that I do not confine my invention to the particular process or preparation, or mode of mixing which I have above described. These are merely pointed out as the most convenient methods that I have discovered of employing my invention, which is the use of nitric acid mixed with water and farinaceous vegetable matter, and exposing it to the degrees of heat stated, so as to thereby produce dextrine-but I do not claim as new, or of my invention, the application of dextrine to the processes I have above mentioned, or any other.

Rep. Pat. Inv.

Specification of a Patent granted to GEORGE HADEN, of the County of Wilts, for Improvements in the Manufacture of a Soap or Composition applicable to the Felting, and other Processes employed in the manufacture of Woolen Cloth, and other Purposes for which Soap is usually employed.-[Sealed October 8, 1838.]

My invention relates to the application of castor-oil, in substitution of the oils and other fatty matters heretofore used in soap making, whether for the processes of manufacturing woolen cloth or other purposes. The various modes of manufactoring soap being well known, and as my improvement by the application of castor-oil, does not interfere with such processes, it will not be necessary to enter into any particular description thereof, and the soap-maker will, as heretofore, vary the materials compounded with the castor-oil, according to the object he desires to attain.

I have found that the mixing at the rate of five cwt. of castor-oil with the caustic leys produced from one hundred weight of salts of soda, produces a very good quality of soap, when boiled and treated in the usual manner of soap boiling. I would, however, remark, that I do not confine myself to any particular quantities, nor to any particular matters which are to be mixed with castor-oil in the making of soap, as they will necessarily vary, as heretofore, in making soap from oil or other fatty matters.

The plant which produces the castor bean is well known to be very productive, and will grow freely in the colonies of the British crown, particularly in the West Indies, and will become extensively in demand when soap is made therefrom, and may be produced and brought to England at a very low cost, and render this country independant of foreign produce. And I would have it understood, that what I claim as my invention is the application of castor-oil in substitution of the oils and other fatty matters heretofore employed in soap making.

Ibid.

Specification of a patent granted to Oglethorpe WAKELIN BARRATT, of Birmingham, in the county of Warwick, for his invention of certain improvements in the process of decomposing muriate of soda for the manufacture of mineral alkali and other valuable products.-[Sealed 19th January, 1839.]

In the common method of manufacturing sulphate of soda by decomposing muriate of soda or common salt with sulphuric acid and exposing the mixture to a strong heat in a furnace, muriatic acid gas is disengaged and is with difficulty condensed. Now the objects of these improvements in the said manufacture are the following:-Firstly, to effect the decomposition of the common salt without the application of heat and without the escape of muriatic acid gas, and which improvements are effected in the following

manner:

To about one hundred and thirty parts by weight of common salt dissolved in four hundred parts of water, add one hundred parts of concentrated sulphuric acid, and to this mixture put in sixty parts of metallic zinc in pieces of moderate size; on adding the zinc hydrogen gas is evolved or given off, which gas is to be collected in the usual way in any of the well-known apparatus for collecting and burning gases. The hydrogen gas so collected may be burnt and applied to the purposes of evaporation, or to any other purpose where light or heat is required.

تم

When the zinc is dissolved, and time allowed for the sulphate of soda to form, or crystallize, draw off the clear supernatant solution, which contains chloride of zinc and a portion of sulphate of soda: then subject this solution to the action of heat, and by evaporation and cooling the remaining portion of sulphate of soda crystallizes, which is then added to the first crop. After this, wash the sulphate of soda in a hot saturated solution of common salt, which separates any chloride of zinc which may have remained mixed with the sulphate of soda.

In the above process it is evident that no heat is employed in the decomposition of the common salt, and that no muriatic gas escapes during such operation.

The object of the second process is to collect a portion of muriatic acid gas evolved from the mixture of muriate of soda and sulphuric acid when first brought together in a cold state, and then to finish off the charge or complete the decomposition of the salt and form the sulphate of soda by continuing or carrying out the process hereinbefore described. In this second process or operation an apparatus is employed suitable for the purpose-that known by the name of Woulfe's apparatus will answer very well.

To one hundred and thirty parts of common salt add one hundred parts of concentrated sulphuric acid. The vessel containing the salt and acid must be so constructed as to admit of the mixture being occasionally stirred with any convenient instrument or agitator, as a rake to facilitate the decomposition of the common salt, that portion of muriatic acid gas which is wished to be collected, being taken up by the water in the Woulfe's apparatus, in the form of liquid muriatic acid.

When muriatic acid gas ceases to evolve, and before the vessels are unluted, add to the charge of salt and acid four hundred parts of water; then remove the vessels containing the liquid muriatic acid, and add to the charge sufficient zinc to complete the decomposition of the common salt.

The quantity of zinc required for this purpose will be found to be about one third less than in the first process.

The hydrogen gas evolved from the mixture or charge is to be collected and applied; then crystallize the sulphate of soda and proceed as already

described.

The solution of chloride of zinc obtained in the above-described processes is to be decomposed by means of any convenient agent so as to separate the oxide of zinc. The patentee has found lime to answer this purpose with the greatest economy: sixty-four parts of zinc dissolved will require for this purpose about fifty-six parts of lime of the best quality and reduced to the state of cream of lime by slacking and mixing with water; but if after the addition of this proportion of lime the solution should by the well-known tests appear to contain excess of acid, more lime must be used till it ceases to do so.

The oxide of zinc thus precipitated is to be washed with a large quantity of water, to free it as perfectly as possible from chloride of calcium: it may then be used instead of metallic zinc for the purpose of decomposing fresh portions of common salt.

The patentee says he would remark, that the oxide precipitated from the solution of chloride of zinc, containing sixty-four parts of the metal, being used instead of the same quantity of metallic zinc, a little allowance should be made for the loss unavoidable in the process. Or the oxide may be employed as a pigment, or in the manufacture of glass, or for any other purpose to which it is applicable.

It will be evident that the native carbonate of zinc and also sulphate of zinc may be used instead of metallic zinc and the above-described oxide of zinc; but they have not been found to be so advantageous under common circumstances-still he claims their use as part of his invention.

The patentee says, in conclusion, "I wish it to be understood that I do not confine myself to the use of any particular apparatus hereinbefore mentioned; nor do I claim any privilege with respect to such apparatus, nor the preparation of the muriatic acid. And I do not claim lime as a precipitant of zinc, nor the producing hydrogen gas from the decomposition of water. But I claim as my invention the use and application of zinc in any form in the decomposition of common salt, and in the manufacture of sulphate of soda; I also claim as my invention the producing of hydrogen gas during the decomposition of muriate of soda; and lastly, I claim as my invention the chloride of zinc as produced during the decomposition of muriate of soda. And I would remark, that I do not intend to confine myself to the proportions here stated, as other proportions may be used, but not with such advantage."

Lond. Jour. Arts & Sci.

Specification of a patent granted to MILES BERRY, of the county of Middlesex, for an invention of a new and improved method or process of alloying metals by cementation, particularly applicable to the preservation of copper, wrought or cast iron, and other metals; thereby operating a change in the appearance of their surfaces and giving them more brilliancy; being a communication made to him by a foreigner residing abroad.-[Sealed 3d May, 1838.]

Alloying or changing of metals by cementation is a process well known in metallurgy, but I am not aware that any metal has ever been before so changed or protected by this process, that it could resist the action of air or humidity, or of certain acids; whereas, copper and iron, both wrought and cast, and other oxidizable metals, when they have been subjected to the said process, according as the same is modified to suit each particular description of metal, will be found to resist all these sources of oxidation.

And first, as regards copper, after it has been well cleansed, it is placed in a furnace, covered with a mixture of charcoal and powder of zinc, and the temperature then raised to cherry red, which degree of temperature is kept up for a longer or shorter period, according to the bulk of the article, or to the desired thickness of the coating and color to be given to the article. The operation is one of great nicety, for which I am informed no definite rules can be laid down, but, that experience will enable any competent workman to effect it with sufficient exactness. It will be found, that in every case, there is a point at which the copper when taken out of the furnace is perfectly inoxidizable, whereas, if the operation lasts too long, the product is nothing but common brass, very readily oxidized.

Second, with respect to iron: for the protection of this metal, two parts of zinc and three parts of copper are melted together in a crucible or any other suitable vessel, and into this mixture or alloy, the piece of iron after being well cleaned, is plunged. If bulky, the article is heated before it is dipped into the crucible, and the better to exclude the atmosphere, the zinc and copper bath is covered with a layer of sal-ammoniac, or melted rosin, or borate of soda, or other suitable substance, preferring however, the sal-ammoniac, which is found in practice to answer better than any other interposed medium.

The process thus described is occasionally reversed, that is to say, a boiling solution of the sal-ammoniac, or of borate of soda, is prepared, and the iron dipped therein before immersing it in the zinc and copper bath, but I am not advised to recommend this process as preferable to the other.

The article being prepared by one or other of these methods, is put into a layer of charcoal powder in a furnace, and exposed to a strong red heat, until the fumes of zinc begin to abate. It is not well to wait until the vapours indicate no longer any zinc. The quicker the operation, the better is the result. The piece of iron must be taken out of the furnace still covered with charcoal, and in that state plunged into water, or allowed to cool slowly.

A third modification of the process is as follows:-an alloy is made of zinc and copper in the proportions aforesaid, namely, two parts of zinc to three parts of copper, and when cooled it is put into a mortar with a quantity of borax, and pulverized. The iron well scoured and cleaned, is then smeared over with fat, oil, grease, or other unctuous substance, or merely wetted with water, and when thus prepared it is dipped into the zinc and copper powder, whence it is taken to be plunged into charcoal powder, and subjected to a strong red heat as hereinbefore directed, until the fumes of zinc begin to abate.

A fourth variety of the process is to dip the iron into a solution of sulphate of copper (after being perfectly cleaned), and to suffer it to remain there for a time. As soon as the iron is covered with a sufficient coating of precipitated copper, it is taken out, plastered over with potters' earth mixed with water, and then covered with a layer of pulverized zinc and borate of soda, or other substitute for the same; or the pulverized zinc and borate of soda or other substitute may be made into a paste, with the clay and water, and the article smeared over with the said paste. The iron is then placed in the furnace, covered with charcoal powder, and heated to a white heat for some minutes. The rest of the process is the same as before described.

The metals thus rendered inoxidizable, are either of a gold or silver hue, according to the length of the operation or the quantity of zinc that combines with the copper. The brightness of the gold colored alloy may be enhanced by rubbing the article with vegetable charcoal, or the soot from a wood fire and nitric acid. It is proper to add, that instead of pulverized zinc, I have been informed pulverized calamine may be used.

And having now fully specified all that has been disclosed or is known to me of the said process, I declare that I claim as new the process of alloying by cementation as hereinbefore described in its several varieties, by which copper, iron, and other oxidizable metals are preserved from oxidation, their surfaces are changed in appearance, and also rendered more brilliant.

Ibid,

To ORLANDO JONES, of the county of Middlesex, for improvements in the manufacture of starch, and the converting of the refuse arising in or from such manufacture to divers useful purposes.--[Sealed 27th February, 1839.] These improvements in the manufacture of starch and in the converting of the refuse arising in or from such manufacture to divers useful purposes, consist in the following modes of operating:

Firstly, I have discovered that the introduction of saccharine matter among the farinaceous materials employed in the manufacture of starch is beneficial in promoting the vinous fermentation; secondly, that the introducVOL. XXV.--No. 2, FEBRUARY 1840.

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