1872.] Electricity. 531 
which Berzelius and Gelis have obtained by rapidly heating sugar to 160°. By 
heating sugar for eight days consecutively in sealed tubes in steam of 5 atmo- 
spheres pressure (75 lbs. to the square inch, and 153° C.), the sugar is con- 
verted chiefly into carameline, CyzH,O,. M. Maumené states that sugar, 
while being refined or extracted on the large scale, should never be submitted 
to a higher temperature than 75°, because below that degree of heat sugar is 
not perceptibly altered. 
It is generally admitted that water freezes at 0°, and can only be cooled 
down below its freezing-point by being kept perfe@tly tranquil. This holds 
good for a cold of —10° or —12°, but is, according to C. Tellier, not true for 
temperatures of —3° or —4°; because water may be cooled down to these 
degrees of temperature, and will not freeze, even when the vessel containing 
it is very violently shaken or stirred. Only a sudden and very violent shock 
to the vessel will cause the water to become frozen, the temperature rising 
to o°; but if, in water cooled down to —3° or —4°, the slightest particle of ice 
or snow is put, congelation briskly sets in and crystallisation ensues, just as 
in a supersaturated solution of sulphate of soda. Praétically this observation is 
important, as it proves the necessity of water containing ice if it is desired to 
coolit down to o° precisely. 
Asbestos resists the joint action of friction, humidity, and high temperature, 
and has therefore been proposed by M. Day as an excellent and durable sub- 
stitute for hemp or flax in the stuffing-boxes of steam-engines. 
The inconveniences attending the application of chloride of zinc and so- 
called water-glass solution for protection of wood from fire are well known ; 
according to F. Sieburger, it is preferable to first coat or wash the wood twice 
with a hot and saturated solution of 3 parts of alum and 1 part of sulphate of 
iron, and next with a more dilute solution of sulphate of iron, to which sufficient 
pipe-clay has been added to render it as thick as ordinary oil paint. Another 
excellent method is to repeatedly paint the wood with a hot solution of glue, 
until a thin coat of glue remains on the surface; then the wood is painted 
with a thicker solution of glue; a mixture of 1 part of sulphur, 1 part of ochre 
or pipe-clay, and 6 parts of sulphate of iron, is applied with a dredger, the 
ingredients having been first separately pulverised and thoroughly mixed. 
M. Ch. Méne states that some officers of the Austrian navy have made ex- 
periments for causing the smoke arising from the fuel consumed in steam- 
ships to be discharged under water by the aid of a blowing machine; at the 
same time a more active and regular combustion is obtained, and the chances 
of fire on board greatly lessened, while the funnel or iron chimney, one of the 
most vulnerable parts above deck, is rendered unnecessary. There is reason 
to believe that the experiments were in every respect successful. 
In order to test whether any bearings or parts of machinery become heated 
by friction, Dr. Mayer proposes to cover the parts with a thin layer of iodide 
of mercury, as this red-coloured salt becomes black when exposed to a tem- 
perature of about 70°. 
We are indebted to M. Collet for an account of the spontaneous combustion 
of a wooden beam ina building at Ribemont (Aisne). The oak beam was 
found to be on fire during one of the hot days in the summer; it was direly 
exposed in an open yard to the concentrated heat of the sun’s rays; the com- 
bustion, although proceeding slowly, was quite distin@, but was not attended 
with flame; the smoke, however, had a peculiar appearance, and on blowing 
the wood it burst into flame. The author asserts that the fire was entirely 
due to the heat of the sun. 
ELECTRICITY. 
Captain Hans Busk has designed an eledtric bell aneroid, which indicates, 
by ringing one or other of a series of ten different bells, any change in the 
atmospheric pressure, amounting to 1-r1oth of an inch on the barometric scale. 
The mechanism is put in ation by a constant battery of twelve Leclanché 
cells. The bells are arranged in the back of the aneroid case, which is con- 
structed similarly to that of a bracket clock, and to each bell is attached an 
