486 
POPULAR SCIENCE REVIEW. 
From these experiments it was shown that phosphorus in a luminous state 
produced phosphorous and phosphoric acids, and ozone also ; that it was 
non-luminous in a degree of temperature below 39° (F.), and that it was lu- 
minous above 45° (F.) ; but the temperature of luminosity and non-luminosity 
varied with the pressure of the atmosphere, and also with the direction 
of the wind. A series of experiments, extending over four years, had been 
made on the luminosity of phosphorus in connection with atmospheric con- 
ditions, and from the results it would appear that the equatorial or sea 
wind is that of phosphoresence and ozone, and that the polar or land wind 
is that of non-luminosity and no ozone. As the ocean is the reservoir of 
ozone, Dr. Moffat asks if it is not probable that its phosphorescence is the 
chief source of its development — a probability strengthened by the fact 
that the polar and land winds, in the shape of the NE. and SE. nodes, seem 
to modify its development as the land-current does. 
Expansion of Limestone when burnt . — Herren Dorlhan and Saminn point 
out that two cylinders formed out of the same piece of limestone measured 
27 millimetres in length and 17 millimetres in diameter. After being com- 
pletely burned, their volume had increased nearly — viz., to 28 millimetres 
and 17-7 millimetres. 
Measuring the Transparency of the Air . — M. de la Dive, of Geneva, lately 
sent a note to the French Academy, describing an apparatus for measuring 
the transparency of the air. According to M. de la Rive, the great trans- 
parency of the air before rain is due to the presence, in the air, of a quan- 
tity of invisible vapour, which renders transparent the numerous germs 
floating in the air, to whose presence light mists are attributed. — Vide 
Comptes Rendus, tom. lxiv., No. 23. 
The Electro-deposition of Copper . — It very frequently occurs that the copper 
which is deposited by electric means is so brittle as to render it unfit for 
manufacturing purposes. A very simple and ingenious method of preventing 
this has been described by M. Bouillet, which we give our readers. M. 
Bouillet has found that a small quantity of gelatine dissolved in the water 
of the bath gives a copper of extensive malleability and nearly equal to 
rolled copper. 
A Telegraphic Thermometer has been, constructed by Professor Wheatstone, 
and was described at the British Association meeting. The details of its ar- 
rangement are too numerous for our columns, but the instrument is likely to 
be of immense value in meteorological inquiries. Professor Wheatstone 
gives the following account of its application to the purposes of meteoro- 
logy : — In this class of instruments the indications are not spontaneously 
conveyed to the observer, but they must be asked for j and whenever this is 
done, the indications will be immediately transmitted to him, however 
frequently the question is put. The uses to which this telegraphic thermo- 
meter may be applied are, among others, the following : — The responder may 
be placed at the top df a high mountain and left there for any length of 
time, while its indications may be read at any station below. Thus, if there 
should be no insuperable difficulties in placing the wires, the indications of 
a thermometer placed at the summit of Mont Blanc may be read as often 
as required at Chamouni. A year’s hourly observations under such circum- 
stances would no doubt be of great value. If it be required to ascertain 
