SCIENTIFIC SUMMARY. 
117 
spectively ; of whicli onl}"88'63 aud 78'17 represented the extractable sugar. 
Now the values of these two sugars, according to the usual method of 
judging by types, would have been the same in each case, at the rate of 54 
francs 50 centimes per 100 hilogrammes, but with the aid of the molas- 
someter, the values were ascertained to be, in the one case, at the rate of 54 
francs 69 centimes per 100 kilos,, and in the other, only 47 francs 25 cen- 
times ; so that an English sugar refiner, buying by colour, according to the 
Dutch system of types, would have paid, in one case, exactly 7*44 per 100 
kilos, above its real value. — Vide Journal of the Society of Arts, Oct. 18. 
Meteorological Value of the Storm-glass, — The camphor storm-glass is an 
instrument so popular among amateurs, and so liable to error in its predic- 
tions, that we are glad to lay before our readers a thorough expose of its 
inefficiency as an instrument of scientific research. Mr. Tomlinson, of King’s 
College — whose researches on camphor are familiar to most physicists — has 
written to the Chemical News, to say that, from the high praise given to the 
storm-glass by the late Admiral Fitzroy, he was led to examine the instru- 
ment -with some care ; and this is what he says of it : — I made one on a 
large scale, in a quart bottle, placed it on the window ledge, and kept a 
journal of its behaviour during some months. The conclusion I arrived at 
was, that the storm-glass is not acted on by light, or atmospheric electricity, 
or wind or rain, &c., but solely by variations in temperature ; that it is, in 
fact, a rude kind of thermoscope, vastly inferior to an ordinary thermometer, 
and has no meteorological value whatever.” My paper on the subject is 
printed in the Philosophical Magazine for August 1863. It produced a few 
remonstrances, to the effect that I had degraded a pleasing instrument to 
the level of a toy. I believe it to be, as you replied to your correspondent, 
only a toy, but it is a very pretty one, and exhibits effects of crystallisation 
of great beauty and variety. I generally have one hanging up in a back 
window, and it affords me pleasure to look at it and to show it to my 
friends.” — See Chemical News, Nov. 1. 
Curious Phenomena of Projectiles. — In some remarks to the Academy of 
Science.s, ]\T. Dumas described some very curious experiments made by M. 
Melsens. By causing a leaden ball to fall into water from the height of 
about a metre, M. Melsens found that the ball drew along vrith it twenty 
times its volume of air. This same ball projected several metres, by powder, 
to the interior of a cylinder, filled with water, the two vertical openings of 
which are shut by diaphragms of plaster, introduced into the cylinder nearly 
a hundred times its volume of air. If the initial velocity is small, the hole 
is about the same size as the ball (11 millimetres) ; by increasing the velocity 
it is much enlarged in size, and when considerably increased the hole becomes 
enormous. It is impossible to assign the cause of the increase of the hole 
to the ball alone. Also, when the velocity of projection is excessive, there 
is a double border inside and outside, formed round the holes where the ball 
enters and quits. — Vide Comptes PcquIus, Sept. 30. 
A Thermometer for the Windoio. — Mr. Moginie of Messrs. Bakers, of 
Holborn, has contrived an ingenious modification of the ordinary thermometer, 
which may be found convenient by those who keep an instrument of this 
kind outside their window. The frame is somewhat wedge-shaped instead 
of quadrangular ; by this means the observer on looking at the scale sees the 
