^54* LIQUOR FOR KENDERING STUFFS WATER-PROOF. 



which is gela- I no longer doubted that a certain quantity of animal ge* 

 latlne had been put into this compofition, with ihe intention 

 of giving greater vifcoftty to the liquor, and enabling it to 

 fupport, for a longer time and more effe6tively, the parts of 

 the oil in fufpention. It is probably by heat and by a com^ 

 niencement of decompofition, that the animal gelatine had be* 

 come infoluble in water; but I perceived that the liquor con- 

 taining the faltalfo held fome of it in folution, for the muri- 

 atic acid and infufion of galls ftill formed precipitates in it, 

 . only lefs abundant than the firti time. 



Ijramination of Sixth Experiment. — In this experiment I endeavoured to 

 aL^' ^ ' ^^^^^ ^^® nature of the fat fubftance retained in the filter, and 

 of which I have fpoken above: my intention was principally 

 to difcover whether it held fome other fubftance in combi- 

 nation. 



For this purpofe I burned it with the filter in a platina cru- 

 cible ; it exhaled a vapour fjmilar to that of tallow or the oilsj 

 it left fome adics, of which the filter had furniflied a part : I 

 found a fmall quantity of alumine in them, which could only 

 proce<^d from the oil, for the bibulous paper did not contain 

 an atom. I am alfo of opinion, that, in addition to the alu- 

 mine, this oil contained a fmall quantity of animal matter, 

 but I cannot pofitively aflert it. 

 which retained Thus, notwithftanding the excefs of acid which exifted in 

 fome alumine in ihe liquor, the oil in precipitating carried with it, and re- 

 tained in combination, fome alumine, and probably fome ani- 

 mal gelatine. 

 It 13 a combina- Hence the fubftance which, by uniting with fluffs, ren- 

 tion of oil, alu- ^^j.^ them impermeable to water, is not the oil alone, but a 

 mme, and am- -i-rin i, ? i ^ , ^ 



mal gelatine J combination ot this fubltance with the alumme, and probably 



with the animal gelatine, which renders this property more 



durable, 

 and yields a little Seventh Experiment. — The liquor which I bad fucceflively 

 ^°<*^^^^^"^P^^^^ deprived of the oil, the alumine, and, in part, of the animal 



matter, by the different procetTes mentioned above, ^ave me, 



by a flow evaporation, cryftals of a fait compofed of foda and 



fulphate of potafli. 

 Another ana- Eighth Experiment. — I made a better analyfis of this liquor 



^^^* by another procefs, which I (hall detail very briefly. 



I precipitated the alumine and the oil by lime-wafer ; I 



collc6led, waftied, and calcined the precipitate : that wbich 



remained in the crucible was alumine and lime. 



4 The 



