1819.] Scientific Intelligence. $11 
to these analyses, that they neither agree with each other, with 
the preceding analyses of the phosphates by Berzelius, nor with 
the weight of an atom of phosphoric acid as deduced from my 
experiments on phosphuretted hydrogen gas. Chemists have 
not yet hit upon an unexceptionable mode of analyzing the phos- 
phates. Further researches are wanting to put us in possession 
of the true constitution of these bodies. 
V. Meagre Nephrite. 
There is a green coloured mineral which occurs likewise at 
Hartmannsdorf, the specific gravity of which is 2-392. It has 
been considered as a variety of nephrite, and distinguished by 
the name of meagre nephrite. But from the analysis of Zellner, 
there is reason to conclude that it is nothing else than an impure 
variety of quartz. He found its constituents as follows : 
I te ee cee cae 92-50 
ame Ormron. oes. acces TDU 
MEL Se ote eee hs Ararven Weg leas". 
PIAEIOSA ys' se sos os ae ee -- 0-50 
Alnmuuia. ee. S Aaenwe.d bet 
Oxide of manganese. ...... 0°25 
6 oc ARICA AC HA eras 3°50 
99875 
LGB. HES e PURE. THOS 
100°00 
(Gilbert’s Annalen der Physik, lix. 181.) 
VI. Professor Mohs’ Observations on Cornwall. 
The following extract of a letter from Professor Mohs to 
Mr. Privy Finance Councillor Blode, has been published in 
Gilbert’s Annalen der Physik, lix. 217. Iam induced to trans- 
late it, because I had the pleasure of meeting with Prof. Mohs 
pretty frequently last summer while in Scotland, and had every 
reason to form a very high opinion both of his abilities and 
his mineralogical skill. He has been appointed the successor of 
Werner at Freyberg, and his reputation as a mineralogist is 
not inferior to that of any person whatever in Germany. 
“In all Cornwall I could observe no greywacke nor grey- 
wacke slate. The ki/las is an intermediate substance between 
mica slate and clay slate, very similar to some varieties which 
occur at Johann-Georgenstadt. It alternates here and there 
with beds of a porphyry, whose basis is an intimate mixture of 
felspar, quartz, and mica. In some places it alternates with beds 
of greenstone and limestone ; and contains granite in that very 
remarkable relation which I described in a preceding letter 
(namely, that which the English mineralogists, and particularly 
the Huttonians, call granite veins). I believe | have seen all the 
remarkable appearances of this kind. They agree exactly with 
