Philosophical transactions, Vol. L. Part I. For the year 1757. / Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.

by Various; Royal Society

Exp. 17. A quantity of the water being kept for some time in a boiling heat, and after it was cool being filtred quite clear from its ochrous matter, it still retained a subacid and aluminous taste in a very strong degree.

18. To an ounce of common spring-water there was added two gutts of fresh sweet milk. This mixture being shaken, the milk mixed intimately with the water, without any kind of coagulation.

19. The same experiment being made with the mineral water, the milk, upon its affusion, was so curdled, or separated into clouds, that the greatest shaking could not mix or incorporate it with the water.

20. This experiment being also made with a weak solution of alum in spring-water, its effects upon the milk were not in the least different from those of the mineral water.

21. And the same trial being again repeated with the water, when boiled and filtred from its ochrous parts, the milk was in the same manner coagulated as before elixation.

22. One part of sweet milk being added to four parts of the mineral water, the milk subsided, and formed a cloud in the bottom of the glass, leaving the upper parts of the water clear. This mixture being heartily shaken, the milk mixed so well with the water, that it appeared to be but a very little curdled.

23. When a larger quantity of milk was added to a smaller quantity of water, and even when equal parts of the milk and mineral water were mixed and shaken together, there could be no curdling or coagulation observed.

24. An equal quantity of the water and milk being boiled together, the greatest part of the milk was coagulated into a thick white curd; and the remainder, with the mineral water, turned of a pure white milky colour, which drank like whey, and was very agreeable.

25. Eight gutts of sweet milk being added to four ounces of the water, and the mixture boiled, part of the milk was thereby curdled, and swam upon the top of the water. The ochrous parts of the water were likewise separated, and falling to the bottom, their colour did not appear of a clear yellow, as usual, but was something milky.

All these experiments strongly indicate the existence of alum in this water. It retains its aluminous taste, and coagulates milk, after the chalybeat parts are almost all expelled by elixation. The coagulation of the milk demonstrates an acidity in the water, and the other appearances shew that acidity to be owing to an aluminous salt.