Note 2 — Chapter III · THE VARIETIES OF FOOD.
Reading edition
The fat to be analysed is saponified with soda or potash, and then the fatty acid set free by hydrochloric acid. If water be now added, 11 or 12 per cent. of the fatty acid will be dissolved, if the fat is butter; less than this if it is a mixture; and not more than 5 per cent. if no butter is present in the fat.