PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 341 



Stearine-|-6HO=g-lycerine-|-3 stearic acid and 3 water. 



Stearinp C TT O ( ^^^ '' ^* 



Cieaiine yjm -nno '-'i2__q Gfpflvip arid JC H O 



6 Water E, e"""^ '^teaiic acid -j L^, ti,, U, 



1 Glycerine . . C e Hg Og 



C,i4 Hi, 5 Oi8 3 Water Hj O3 



'^114 -tine Ui3 



Stearine, palmatine, margarine and olein consist, therefore, of stearic, 

 palmitic, margaric and oleic acids, with the base glycerine. In soap- 

 making, the following decomposition takes place: 



Ch4 Hno 0,, + 6(IIO)-f3(KO)=3(KO) + 3(03e H35 03)+Ce H^ 0,+3(H0) 



The stearate of glycerine is decomposefl and stearate of potash is formed. 

 We substitute for the base, glycerine, in the original combination, a new, 

 stronger base, potash, and form the new salt known as soap. 



[The speaker next described the several acids mentioned, and pointed 

 out the proper methods of detecting the various adulterations used in the 

 manufacture of soap.] 



The President. — There is a gentleman present who will give us some 

 information in relation to vegetable soaps. 



Mr. Austin. — In some countries the natives use the seeds of some plants 

 as substitutes for soap, of some plants the bark is used, and of others the 

 root. Such plants •are found to abound in an acrid, narcotic principle — a 

 vegetable alkali, called saponin; but whether their virtues as purifiers of 

 linen depend upon chemical or mechanical action is a question I believe 

 not yet settled. These plants are confined to a very few widely diverse 

 natural orders of the vegetable kingdom, and frequently to a very few 

 genera of those orders. However, it is, no doubt, contained in many plants 

 where it is not at present suspected to exist. I will mention briefly a few 

 of the more important plants containing saponaceous secretions. The seeds 

 of many plapts of the soap-berry family, as the horse-chestnut, contain this 

 matter to a great extent. The fruits of these latter lather freely in water, 

 and " a few of them will cleanse more linen than sixty times their weight 

 of soap." Pounded and thrown into water they stupefy fish. 



There are two or three genera belonging to the natural order — Rosacea} 

 and the tribe Guillaite — remarkable for their saponaceous secretions. Guil- 

 laia saponaria yields one of the barks called Guillaia, used as a substitute 

 for soap. " Two ounces of this bark are sufficient to wash a dress," and it 

 is said to give a remarkable luster to wool. It contains a substance which 

 occasions voilent sneezing, and which is allied to saponin. 



The California soap plant belongs to the natural order — Lilliacea', and to 

 the Scillce or onion tribe. It is u'sed by the natives as a substitute for soap. 

 This plant produces a thick bulb, which is inclosed in a remarkably large 

 and thick bundle of black, coarse fibers — the remains of the nerves of 

 former leaves. 



All plaots secreting saponaceous matter (and I have mentioned only 

 some of the more important ones) contain also an acrid, narcotic, and often 

 highly poisonous principle, and, no doubt, the two principles are identi«:al 



