400 Scientific Intelligence. [May, 
carbonate were dissolved with the proper precautions in nitric acid. 
This experiment was twice repeated. ‘The loss of weight each time 
was 29'9 grains. ‘Therefore carbonate of strontian is composed of 
Garbponie acid “62%... eniaiee 29°9 or 1 atom 
Strontian ......, oo ps ote ge orl 
1000 ; 
‘Hence it follows that an atom of strontian weighs 6-449. I con- 
sider this result as agreeing sufficiently with Klaproth’s experiments. 
He found that the native carbonate lost 30 grains when dissolved in 
an acid. Now as this mineral contains a mixture of carbonate of 
lime, it ought to lose more weight when dissolved in an acid than 
pure carbonate of strontian ; for carbonate of lime contains 43-2 
percent. of carbonic acid. If we suppose my experiments correct, 
and native carbonate of strontian to contain 14 per cent. of car- 
bonate of lime, it ought, when dissolved in an acid, to lose 30:086 
grains in weight. Now this almost agrees with the experiment of 
Klaproth. The difference does not amount to 51. part. 
X. Number of Plants known. 
According to Humboldt, the species of plants at present known 
amount to 44,000. Of these, 6,000 are cryptogamous; the re- 
maining 38,C00 have flowers. The distribution of these 38,000 
phanerogamous plants is, according to Humboldt, as follows :— 
Burope” vines nas op Sie csi s «8 1G) s ee 
Temperate regions of Asia ....... 0 te e's he. Rae 
Asia, within the tropics andislands ...... 4,500 
AGPICA, nin tekioln » ee ciate Sa enh 6 d,s Rina asd diet oy eee 
Both temperate regions of America ...... 4,000 
America between the tropics ............ 13,000 
New Holland, and islands in the Pacific .. 5,000 
38,000 
The plants described by the Greeks, Romans, and Arabians, 
scarcely amounted to 1,400. (Humboldt’s Nova Genera et Species 
Plantarum, Prolegomena, p. 11. 
XI. Verdigris. 
Hitherto verdigris has been chiefly manufactured in France ; 
but a manufactory of it has lately been established at Deptford, near 
London. I had the curiosity to examine a portion of this verdi- 
gris, that I might be able to compare it with the French, the 
composition of which was already known to chemists from the ex- 
periments of Proust. 
100 grains of the verdigris being digested for some time in 
about a pint of distilled water, the whole was thrown upon a filter. 
I was surprised at the length of time requisite to allow the liquid 
portion to pass through the filter. At least a fortnight elapsed before 
