1866.] Physics. 125 
5. If the part frozen is not extensive, and only a few disor- 
ganized blood globules pass into the circulation, the animal may 
recover. 
6. But if, on the contrary, the frozen part is of considerable 
extent, then the mass of altered globules brought into the circula- 
tion when the part is thawed, rapidly kills the animal. 
7. For this reason a half-frozen animal may live a long time if 
maintained in the condition, since the altered globules do not get 
into the circulation, but it expires rapidly as soon as the frozen part 
is thawed. 
8. In all cases of congelation, death is due to the alteration of 
the blood globules, and not to any effect on the nervous system. 
9. It results from these facts that the less rapidly a frozen part 
is thawed, the more slowly the altered globules find their way into 
the circulation, and the greater are the chances of the recovery of 
the animal. 
The Abbé Moigno gives, in his valuable review ‘Les Mondes,’ a 
short description of an ice-making machine now in operation here. 
The inventor, M. Menard, employs ether, which is compressed to 
the extent of from five to seven atmospheres. From the reservoir 
the liquid is allowed to escape into a worm, circulating round square 
vessels of water, which become frozen by vaporization of the ether 
in the worm. The machine will produce, it is said, fifty kilogrammes 
of ice per hour. 
Execrriciry.— The highly electro-positive metal Magnesium 
would be invaluable to electricians if it could be got for the same 
price as zinc; already it is being proposed for use in certain elec- 
trical apparatus, and at a recent meeting of the French Academy, 
M. Bultinck presented a note on the Use of Magnesium in Voltaic 
Piles in place of Zinc. The author shows that a short chain of 
twenty elements, each composed of thirty-five millimetres of thin 
silver and magnesium wires, wound about pieces of caoutchoue and 
properly connected, will produce all the effects, chemical, physical, 
and physiological, of a long Pulvermacher’s chain when simply 
moistened with pure water. 
It is announced that the two lighthouses at Havre will now 
be definitely illuminated by electricity, that all difficulties in the 
way of producing a constant light by induction machines have now 
been overcome by the Alliance Company. The machines will be 
driven by a six-horse power locomotive engine, which will also com- 
press air for whistles or trumpets to be used as fog signals. 
