THE TECHNOLOGIST. [March i, 1865. 



«i4b OX CHEMISTRY APPLIED TO THE ARTS. 



raises the boiling point of the liquor), and the contents of the vessels 

 are kept roiling for about an hour so as to exclude all air, and destroy, 

 by the high temperature, all the sporules or germs of putrefaction they 

 may contain, when they are hermetically closed. M. Chevalier Appert 

 has improved this process by placing the prepared vessels in a closed 

 boiler, by which means he raises the temperature (by pressure) to 234°, 

 effecting thus the same purpose more rapidly and economically. To 

 give you an idea of the extent of this trade, I may state that 

 M. Chevalier Appert prepared above 50,000 lbs. of meat for 

 the French army in the Crimea. I am aware that many modifications 

 have been applied to this process, but I shall only mention that of Mr. 

 J. McCall, who adds to the previous principle of preservation a small 

 cpiantity of sulphate of soda, well known to be a powerful antiseptic. 

 The beautiful specimens now on the table, which have been kindly lent 

 to me by Messrs. Fortnum and Mason and by Mr. McCall, will satisfy 

 you of the applicability of the above-named methods for the preserva- 

 tion of meat and other animal substances. But before concluding this 

 part of my lecture, I must add that the preservation of animal and 

 vegetable substances by the exclusion of air and cryptogamic sporules 

 is also effected by other methods than those above described ; for 

 instance, they are imbedded in oil, or in glycerine, as suggested by Mr. 

 G. Wilson, or in saccharine syrups. I should not forget to mention that 

 several plans have been proposed for protecting animal matter by cover- 

 ing their external surfaces with coatings impermeable to air. Two of 

 the most recent are the following : — M. Pelletier has proposed to cover 

 the animal matter with a laj-er of gum, then immerse it in acetate of 

 alumina, and lastly in a solution of^elatine, allowing the whole to dry 

 on the surface of the animal matter. The characteristic of this method 

 is the use of acetate of alumina which is not only a powerful antiseptic, 

 but also forms an insoluble compound with gelatine, thus protecting 

 the animal matter from external injury. Mr. Pagliari has lately intro- 

 duced a method which is stated to give very good results. It consists 

 in boiling benzoin resin in a solution of alum, immersing the animal 

 matter in the solution, and driving off the excess of moisture by a cur- 

 rent of hot air, which leaves the above antiseptics on the animal matter. 

 It is scarcely necessary to mention the old method of using smoke 

 arising from the combustion of various kinds of wood, except to state 

 that in this case it is the creosote and pyroligneous acids which are the 

 preservative agents. The preservation of animal matter by a very 

 similar action is effected by the use of carbolic acid, a product obtained 

 from coal tar. It is much to be regretted that this substance, which is 

 the most powerful antiseptic known, cannot be made available lor the 

 preservation of food, but there can be no doubt that for the preservation 

 of organic substances intended for use in arts and manufactures, no 

 cheaper or more effective material can be found For example, I have 

 ascertained that one part of carbolic acid, added to five thousand parts 



