SCIENTIFIC SUMMARY. 
439 
metals are alternately at the temperature of the collector and of the diffuser. 
The pattern now in use for lighting a workshop in Paris is 2| metres high, 
■and 1 metre in diameter. Another model, made for the exhibition at the 
Albert Hall, is square and smaller, though of the same power. Each half 
•of the cylindrical battery can be made to supply a powerful electric light, 
while the square one can produce four lights of half the brilliancy. The 
electromotive force is, according to prolonged experiments, 218 Volts, about 
equal to 120 Bunsen cells, while the resistance is only *31 Ohms. The 
large battery consumes 9 or 10 kilogrammes of coke an hour ; the smaller, 
about kilogrammes. The large external surface of the apparatus, radiat- 
ing its heat to the air around, fits it lor warming purposes as well as for 
lighting. 
The Optical Structure of Ice has been investigated by Herr Kiocke, who 
confirms the observation that the optic axis is at right angles to the surface 
whence the cooling proceeds. The ice flowers which first cover the sides of 
the vessel, however, have their principal axis parallel to these. The axis, 
according to M. Bertin, has a definite direction only after a fairly thick 
stratum of ice has been formed, the first layer being confused in its mode of 
crystallization ; but Herr Kiocke shows that the first needles shooting over 
the surface are formed parallel to the principal axis, and their ice plates are 
added to their sides, the optic axis of which is at right angles to the surface 
of the water. 
The Temperature of Carbons giving the Electric light has been examined 
by M. Rossetti, by means of a thermopile, the face of which is placed at a 
suitable distance to receive rays from a radiating surface of determinate size ; 
the thermal effect being measured by a sensitive reflecting galvanometer. 
He comes to the conclusions that — (1.) The positive pole has higher tempera- 
ture than the negative. (2.) The temperatures vary according to the inten- 
sity of the current. (3.) They are higher, the smaller the radiating surface, 
provided it comprises the extreme point. (4.) In the negative pole the 
minimum temperature was 1910° cent., with a large radiating surface of 
small brilliancy ; the maximum 2532° cent., the radiating surface being half 
the preceding. (5.) For the positive pole the minimum temperature was 
2312°, the carbon being large ; the maximum 3200°, with a thin carbon and 
small radiating surface. 
The Velocity of the Wind at Sea has been tested by Admiral Serres in 
the French Frigate La Magicienne , a Robinson anemometer being observed 
daily at a height of 8 metres, and twice daily at that of 36 metres, from the 
sea level. With very rare exceptions it was found much greater in the 
latter case than in the former, the average ratio being 12 to 10. Hence 
the modern practice of increasing the high sails at the expense of the lower 
is justified by observation. 
A New Form of Leclanche Battery has been introduced by the inventor, in 
which the high resistance of the older pattern is diminished, and the em- 
ployment of a porous pot is dispensed with. The carbon is surrounded with 
n mixture of 40 parts of pyrolasite, 155 parts of grain carbon, and 5 parts 
of resin, the latter acting as a cement. This composition is heated to 100° 
cent., and subjected to a pressure of 300 atmospheres. It forms a homo- 
geneous cylinder, in the centre of which is the carbon electrode. The in- 
