4 Dr Brewster on the Connexion between the Optical Structure 
Acetate of Copper and Lime. 
Experiment. 
Theory. 
Acetic Acid, - 42.0 
2 Atoms 
13.0 
41.87 
Peroxide of Copper, 32.0 
1 
10.0 
32.20 
Lime, 
11.4 
1 
3.55 
11.43 
Water, 
14.6 
4 
4.50 
14.50 
100.0 * 
31.05 
100.00 
Bin-acetate of Copper. 
Acetic Acid, 
- 
52.0 
Peroxide of Copper, 
- ■ 
39.6 . 
Water, 
- 
8.4 
100.0 
M. Berzelius, to whom I sent specimens of the blue salt, 
also found it to consist of acetate of lime and deuto-acetate of 
copper, with water of crystallisation. 
The crystals of Nitrate of Strontian present us with another 
example of optical analysis. I examined in 1816 some fine spe- 
cimens of this substance, which Dr Hope had prepared from 
the native carbonate of strontian, and 1 found them to possess 
Two axes of double refraction. In 1817, I received from Mr 
William Allen of Plough Court some beautiful octohedral crys- 
tals of the same salt ; but I was surprised to observe, that it 
had no double refraction at all *f*. This result obviously indi- 
cated a difference of chemical composition ; and I therefore 
transmitted the crystals made by Dr Hope to M. Berzelius, 
who has favoured me with the following observations upon them. 
“ This nitrate of strontian differs from the ordinary nitrate of 
strontian, both in its form, and in the circumstance that it con- 
tains a considerable quantity of water of crystallisation. On the 
supposition that it was a double salt, I gave it to M. Mitscher- 
lich to analyse; but he did not succeed in finding a second base. 
If this salt should prove to be only a nitrate of strontian, with 
water of crystallisation, its production must depend on particu- 
* We understand that Dr Ure observed some instructive peculiarities in ana- 
lysing this salt, which we hope to lay before our readers in an early Number of 
this Journal. *f- See Phil. Trans. 1818, p. 222. & p. 254. 
