403 
of Edinburgh, Session 18 ( 38 - 69 . 
two hundred gallons of proof-spirit, equal in quality and cheapness 
to the best sort of corn-spirit. It is easy, through action of recti- 
fied spirit on extract of carrot-juice, to crystallise from it fine cane- 
sugar, which will account for this result. But the Society’s 
records do not state anywhere what success the inventors attained 
with their new manufacture. 
Dr Kennedy, well known and esteemed at the period as a 
chemical analyst, contributes a careful analysis of a new Zeolite 
from the greenstone of Salisbury Crags, showing that it consists 
almost entirely of silica, lime, and 8£ per cent, of soda; and in 
1798 he communicates a much more interesting account of the 
composition of basalt, greenstone, and lava. In the latter paper 
he comes to the conclusion, that the basalts and greenstones around 
Edinburgh, and, the lavas around Etna, all agree both in the 
nature and the proportion of their main constituents, which are 
silica, alumina, and oxide of iron, with, in all, about 4 per cent, of 
soda. The interest of these facts, in their application to the pre- 
vailing geological doctrines of that period, as well as of the present 
time, will be seen presently, and, indeed, is obvious on the bare 
mention of them. 
In 1791 Dr Black presents his last communication to the Boyal 
Society, his famous analysis of the spouting hot springs of Geyser 
and Rykum in Iceland. In the Transactions this important paper 
is accompanied by another from Mr Stanley of Alderley, M.P., 
from whom Black obtained the waters for examination, and who 
himself collected them during a visit to Iceland in 1789. There 
has appeared since that time no better account of these extra- 
ordinary springs than that given by Mr Stanley, and in some re- 
spects it surpasses more recent narratives in complete and graphic 
description. I know not, indeed, that any subsequent visitor has 
added much to our knowledge until our deceased Fellow, Mr Alex- 
ander Bryson, communicated to this Society his excellent thermo- 
metric observations on the very high temperature attained by the 
waters at great depths in the funnel whence they are projected. 
In Black’s time geologists and chemists were puzzled to account 
for the solution in the water of the great amount of silica neces- 
sary to form the extensive deposits of hard siliceous sinter around 
these fountains. Black’s analysis gave the explanation. Of the 
