102 Scientific Intelligence. 
same sugar may form many compounds with tartaric acid. The author — 
describes only those which he has obtained. For the formulas we must 
refer to the original paper.— Comptes Rendus, xlv, 268. 
{Note.—From the above it will be seen that we owe to Berthelot the 
discovery of the true constitution of three entire series of organic bodies, 
viz., the glycerids or fatty bodies; the sugars and their congeners; an 
the glucosids or acid and neutral bodies which split into sugar and other 
- acid or neutral bodies by boiling with acids, alkalies or water. 
undergoes absorption in doing so, since a sunbeam which has pa 
= 
author points out several methods of employing this salt in photometry, —— 
the most advantageous of which is to collect and measure the quantity 
fa) ic acid absorbed in a given time. The solution is sufficiently 
sensitive for all ordinary purposes. When great sensitiveness is required 
the author recommends the use of the tithonometer invented by him in — 
1843 and since employed in a modified form by Bunsen and Roscoe— _ 
L.and E. Phil. Mag., Sept. 1847, No. 92, p. 161. W. Oe 
8. On the Chemistry of the Primeval Earth; by T. Ry Hunt. 
(Extract of a letter to Prof. J. D. Dana, dated Montreal, Nov. 25, 1857.) 
—The primitive rocks which filled so large a place in the geological sys 
tems of the last century are now being forgotten. We have learned that 
the oldest visible portions of the earth’s crust are made up of sediments, 
presided over the formation of the most ancient rocks known. 
But although the materia prima of the sedimentary rocks has long — 
since been buried beneath its own ruins, its nature offers an interesting — 
subject of consideration to the chemical geologist. ee. 
neous theory of the earth, we may obtain a conception of the nature of og 
be liberated as a volatile acid, 
