SCIENTIFIC SUMMARY. 
437 
radical forms whicli by some may be regarded as one of tbe progenitors of 
diverse berbivorons groups. The sivatherium, according to him, is unlike 
all other living ruminants but one— the ‘prongbuck — from the fact of its 
having had hollow horns, evidently subject to shedding. It differs thus 
from deer whose solid horns annually drop off, and from the antelope tribe, 
sheep, and oxen, whose hollow horns are persistent. Save one living form. 
— the saiga — no recent ruminant possesses, as did the sivatherium, a muzzle 
resembling in several ways the proboscis of the tapirs and elephants. On 
the strength of his own recent researches, and of those of Mr. Bartlett and 
Dr. Caulfield, Dr. Murie is inclined to place the sivatherium in the family 
Antilocapridae. Radiating from the sivatherium can be traced differentia- 
tion of structure allying it to the ancient bramatherium and megacerops. 
Diversely, links lead through the prongbuck towards the deer, giraffe, and 
camel. On the other hand, configurations point undoubtedly to the saiga, 
and there it is, as it were, split into lines directed towards the antelope, the 
sheep, and even the pachyderms. 
Flint Implements in Joshua’s Tomh. — The Abbe Richard gave an account 
of this recent discovery to the British Association at Edinburgh. He thinks 
that it upsets all geological hypotheses as to man’s size. The Abb€ unfor- 
tunately forgets (1) that the tomb may not be that of Joshua at all, and (2) 
that, if it be, there is no evidence as to the time the flint weapons were 
placed there. In fact they may have been, and probably were, there many 
ages before Joshua was placed there. 
Bats of the present and of the Mammoth Periods. — Professor Van Beneden 
read a paper, in French, with this title, before the British Association. So 
far as was gathered, it was an argument against the Darwinian theory. 
MECHANICAL SCIENCE. 
The Rhysimeter. — Under this name, Mr. A. E. Fletcher has described, to 
the British Association, an instrument for measuring the velocity of streams 
of water, or the velocity of a ship relatively to the water through which it 
is moving. The apparatus is very simple. A double tube, with two orifices 
at the bottom, one of which faces the source of the current, while the other 
faces the opposite direction, is held in the stream, and communicates by 
tubes with the indicator where the pressure is measured, by columns of 
ether, water, or mercury, according to the circumstances of the case. The 
rhysimeter is already employed on some of the mail packets running to the 
United States, in place of the patent log, to ascertain the speed of the ship. 
It is more convenient, as giving the speed directly, without a time observa- 
tion. The principle of the instrument is not new, but the construction is an 
improvement on previous instruments. 
Light Railways. — Mr. W. Lawford has read a paper on this subject before 
the Institute of Mechanical Engineers. By light railways, Mr. Lawford 
understands railways of the ordinary narrow gauge, constructed as branches 
from existing trunk lines, but intended to be worked with light, flexible 
rolling stock, and at slow speeds. With a maximum load of 5 tons on one 
YOL. X. — NO. XLI. G G 
