OXALATES, NITRATES, PHOSPHATES, SULPHATES, AND CHLORIDES. 57 
water in their basic character, we find the water of crystallization likewise to be three 
atoms, or a multiple of three, and no other number. 
2. Nitrate of Copper. 
C'UNH3; 
and also 
C u N H 3 -f 3 H. 
There are two nitrates of copper, one of which crystallizes in prisms, and the other 
in rhomboidal plates of a lighter blue colour than the prisms ; the first of which I 
find to contain three and the other six atoms of water. Both are deliquescent to a 
certain degree, the salt which contains the large proportion of water being more so 
than the other. 
(1.) Of the dark blue prisms, 28-12 grains carefully calcined left 8 - 98 grains black 
oxide, or 3T94 per cent. In a second experiment, 22 '9 grains left 7‘34 grains oxide, 
or 32-05 per cent. The salt being neutral in composition, the quantity of nitric acid 
may be inferred from the oxide of copper, and the difference between their sum and 
the weight of the salt operated upon is the water. By the first analysis the water 
amounts to 3-38, and by the second to 3-28 atomic proportions. The excess above 
three atoms is probably hygrometric moisture, to remove which from this salt we 
cannot employ the ordinary means. In a third experiment upon a portion of the 
same salt, which had been dried over sulphuric acid till it began to effloresce, 33-19 
grains of nitrate left 1T04 grains oxide, which gives 2-83 atomic proportions of water 
to the salt, or the result is a little below the three atoms. Hence this nitrate may 
safely be supposed to possess three atoms of water. 
(2.) Of the lighter coloured crystals in plates, 10-60 grains left 2‘78 grains oxide of 
copper when ignited, or 27'36 per cent. Hence the salt is composed of 
With six atoms water. 
Nitrate of copper . 
. . 6-57 
100- 
100- 
Water 
. . 4-03 
6T33 
57’54 
10-6 
16T33 
157-54 
The experimental determination is a little above the theoretical estimate, as might 
be expected from the deliquescent nature of the salt. 
The crystals speedily became opake over sulphuric acid in vacuo, and 10-6 grains 
lost 2*18 grains water in a night, retaining T85 water; which is 28"16 water retained 
to 100 anhydrous salt, or almost exactly three atoms of water. Hence this salt parts 
easily with half its water. The other three atoms of water are retained more strongly; 
for by a second day’s exposure over sulphuric acid there was an additional loss of 
only 0 - 15 grain water ; or the water retained was reduced to 25‘87 parts united to 
100 anhydrous salt. 
MDCCCXXXVII. 
I 
