258 Scientific Intelligence. 
eat. These conditions are, that the metals employed should be as far 
as possible from each other in the thermo-electric series; that they should 
permit great differences of temperature so as to avoid the necessity of 
using ice; that they should not be expensive, and that the insulating 
material should resist a high temperature and possess sufficient solidity 
with a breadth of six inches and a height of six inches. Marcus has 
240 lbs. of coal per day. The Vienna Academy, recognizin 
ance of the discovery, has voted to the inventor the sum of 2500 gulden 
—the invention to be public property.—Pogg. Ann., exxiv, 629, April, 
1865. WwW 
It must be remembered that the step taken by Marcus is, after all, @ 
first step in the right direction. Bunsen, E. Becquerel, and Stefan, have. 
vn that there are thermo-electric combinations of much higher electro- 
motive force than those employed by Marcus, although the internal re- 
aL °¢ is too great to permit of their use in constructing large batteries. 
thea a : 
we Suggest that the thermo-electric relations of the highly crystalline 
nD, anese and carbon, known as “ spiegeleisen,” (that from 
the Franklinite of New Jersey for example,) deserve a careful study. The 
ossession of a galvanic battery in which coal is consumed in place of 
zinc and acids, can hardly fail to revive an interest in electro-magnetic — 
«ey? se that of Page, even if only for cases in which com- 
‘Paratively little power in required, since our. best steam engines do not 
{itd 10 per cent of the work which the consumption of the coal is capa 
ble of doing. CH eee ee : a 
—w. 
