316 
TOrULAR SCIENCE REVIEW. 
evolved during combustion, he had no difficulty in pronouncing that arsenic 
was present ; its presence was experimentally determined, and its quantity 
estimated to be 060 per cent, of the taper, equal to 0*35 grm., or 5*43 grs. 
of arsenious acid — quite enough to poison two people if taken directly in 
the solid form. The red tapers weighed, on an average, about 8 94 grams, 
and burned seventeen minutes, leaving 3 milligrams of ash totally devoid of 
metallic appearance. Mercury, existing as vermilion, was found by 
Reinsch’s process, and its quantity was afterwards carefully determined. 
The amount of mercuric sulphide ultimately collected, washed, and dried, 
was T66 per cent. In one series of experiments, the following results were 
arrived at, white, yellow, blue, red, and green tapers being experimented 
upon : — - 
White. — Perfectly harmless ; little ash. 
Yellow. — Harmless ; coloured with chromate of lead ; ash, metallic. 
Blue. — Harmless ; coloured with ultramarine. 
Red. — Highly poisonous, containing 1*93 per cent, of vermilion ; the 
tapers very highly coloured ; slight ash. 
Green. — Poisonous ; colour due to arsenic ; metallic ash ; quantity of 
arsenic not determined, but probably about 1 per cent. 
GEOLOGY. 
The Carboniferous Plants of Canada have been explored by Dr. J. W. 
Dawson, F.R.S., who has published a series of reports upon the subject, 
which have been reprinted from the “ Transactions of the Geological Society 
of Canada.” The work is said to extend greatly our knowledge of the 
Lower Carboniferous Flora. It also contains a list of the species of the 
Middle and Upper Coal Measures, and discusses the character of Sigillarioid 
and Lepidodendroid stems. 
The British Seas, from a Geological Aspect , have been very carefully de- 
scribed by M. Delesse in his recent work on the subject. With regard to 
the orography of the “ Ocean Britannique,” as M. Delesse calls our seas 
(excepting the Channel and the North Sea), he shows how Britain and 
Ireland stand on a sort of terrace, the boundary of which on the Atlantic 
side coincides sufficiently exactly with the 600 feet contour line (below sea- 
level, of course), in such a manner that were the British Islands elevated 
600 feet they would be joined to France and to Denmark, but the Faroe 
Islands, Iceland, and Rockall would still be islands. As is natural in the 
neighbourhood of a mountainous centre, the surface of this terrace is very 
irregular around Scotland; especially there are to be noted two valleys 
extending under the sea to the West of Scotland, separating it on the one 
hand from the Hebrides, and on the other from Ireland. The littoral de- 
posits of the South of England are naturally very similar to those of the 
North of France, and are equally referable to the geological formations 
along the coast-line. Among the submarine deposits sand stands pre- 
eminent. Next in point of frequency comes gravel, which is found in oddly- 
