te4. = Dr. ‘Fhomson’s First Principles of Chemistry. 
Extract of a letter from Dr. Thomson to Prof. Silliman, dated 
Glasgow, March 30, 1825. 
Dear Srr, 
I po myself the pleasure of sending with this letter a copy 
of a work of mine, just poblished, on what I consider the most 
important point which can at present occupy the attention of 
the chemist. It has cost me five years hard labour, and an 
almost infinite number of experiments. But I have been at 
so much pains to secure accuracy, and have repeated my ex- 
iments so frequently where I considered them as funda- — 
mental, that I entertain the fullest confidence of their almost 
mathematical accuracy. I have been delighted with the sim- 
plicity of the numbers, and with their connexion with each 
other. You will perceive that they raise chemistry to the 
rank of a mathematical science, and that henceforth chem- 
ical analyses may be subjected to the test of mathematical 
ealculation. oe ee 
intend now to devote myself for some time to come, to 
‘@xamine the mineral kingdom. I expect to find the same 
simplicity in the composition of minerals, if we can by any 
means disentangle the true chemical compounds from mix- 
tures. Berzelius and his pupils have done a great deal on 
that subject, and their labours will be of infinite use to me ; 
though I do not approve of the method of calculation employ- 
ed by Berzelius. Probably several years will elapse before 
I shall be in a condition to give any thing to the public on the 
subject. But I have already begun, and have made some ° 
little progress. I find for example, that our magnesian lime- 
“stone is an exact chemical compound of 
n f 
e atom carbonate of lime - 6.25 
Orie atom carbonate of magnesia - 5.25 
11.50 
It gives me much pleasure to see with what spirit you are 
going on in America in investigating the mineralogy of your 
yast continent. America will soon have to boast of many 
exeellent mineralogists, and some accurate chemists. 
