50 SEVENTH REPORT—1837. 
a formula identical with that which belongs to the entire genus of alum 
salts. Dr. Apjohn briefly alluded to the other varieties of alum, both 
those in which the alkalies replace each other, and those in which the 
alumina is replaced by the deutoxide of iron, chrome, or manganese ; 
and pointed out the theoretical possibility of an alum containing no 
metal but manganese. 
On a new Gaseous Compound of Carbon and Hydrogen. 
By E. Davy, Professor of Chemistry, Dublin. 
The gas (a new bicarburet of hydrogen), which was described by 
Professor Davy at the last meeting of the Association in Bristol, 
having been inclosed in a tube furnished with platinum wires, and 
subjected to a series of electric sparks, carbon was deposited, but there 
was no alteration of volume. This residual gas the author conceives 
to be new. It is insoluble in water; not ignited by chlorine; ex- 
ploded with one and a half volume of oxygen, it gives one volume of 
carbonic acid and some water. This gas would therefore appear to 
be a binary compound, and to be represented by the formula C-+-H. 
Professor Davy stated, that his investigations were not concluded, but 
that he hoped to be able to give a fuller paper on the subject at the 
next meeting of the Association. 
Outline of an experimental Inquiry into a peculiar Property of the 
Earth ; the chemical Changes which occur during the germination 
of Seeds; the vegetation of Plants; the formation of vegetable 
Products ; and the renovation of the Atmosphere ; with some Obser- 
vations on the ultimate analysis of Organic Compounds ; the whole 
being in connexion with a series of investigations into the decomposi- 
tion of Vegetable Matter. By Rozert Rice. ; 
The extensive class of subjects included in the title of Mr. Rigg’s 
communication had been investigated by the author through the 
medium of many thousand experiments, the results of which appeared 
to him to establish an harmonious connection between them all, of 
which the following is an abbreviated sketch. The earth retaining 
water, and combining with carbonic acid gas the food of plants; the 
seeds, decomposing the water, forming carbonic acid gas, and a com- 
pound of carbon, hydrogen, nitrogen, and earthy matter; the germ 
which favoured this peculiar decomposition, uniting the latter com- 
pound with the oxygen of the atmosphere; the roots, promoting the 
further decomposition of the water, forming carbonic acid gas, and 
the other compound, (the earth taking up the former if it be not im- 
mediately wanted, the latter entering into the plant as sap) ; the leaves, 
serving the office of reservoirs for atmospheric air and moisture, and for 
performing certain offices respecting the changes effected upon car- 
bonie acid gas ; the whole plant, combining the different elements, so 
as to form the oils, resins, gums, &c. to an unlimited extent, 
