402 Proceedings of the Royal Society 
Philosophy seldom ventured to appear before the Eoyal Society. 
In 1784 Dugald Stewart read an essay on Cause and Effect, and 
in the same session Dr Gregory read another on Cause and Effect 
in Physics. But of neither is there even an abstract in the 
Society’s Proceedings. 
The Chemical papers produced before the Society during the 
first twenty years of its existence — sixteen in number — are not so 
numerous as we might expect, when it is considered that the great 
discovery by Black of the composition of the carbonates, and the 
nature of carbonic acid, was still of rather recent date. But some 
of these papers are of interest, and retain their value in the pre- 
sent day. The most important of them are as follows : — 
That remarkable genius, Lord Dundonald, father of the lately 
deceased naval hero, read in 1784 a characteristic inquiry into the 
purification of sea-salt. Having found that a concentrated solu- 
tion of common sea-salt possesses the property of dissolving a large 
quantity of the magnesian salts, which are always to be found in 
it in small proportion, — rendering it, however, attractive of mois- 
ture in damp air, and less fit for the curing of meat, — he placed 
the salt to be purified in a conical filter, and passed through it two 
or three successive portions of a concentrated hot solution of the 
same impure salt, with the effect of removing almost entirely the 
salts of magnesia. This method was plainly applicable to the 
large manufacturing scale ; and the inventor had only, as in the 
purification of loaf-sugar by pure syrup, to displace the last 
saline liquor remaining in the interstices of the salt, by a solution 
of pure chloride of sodium, when the whole of his product would 
have been quite pure. 
Drs Black and Hutton being appointed with Mr Bussell a com- 
mittee to examine and report on a process proposed for manufac- 
turing spirit from carrots by two enterprising experimentalists, 
Hunter and Thornby, they find that twenty tons of this root yield 
which my attention has been turned in Hugo Arnot’s “ History of Edin- 
burgh ” (1789, p. 323), that the Board of Trustees for Encouragement of 
Manufactures appointed an artist in 1772 to teach twenty boys or girls draw- 
ing, and obtained for the purpose, from the Town Council, the use of two 
rooms in the University. (Dec. 14.) 
