A406 Scientific Intelligence. 
secure these, it will only be necessary to erect a short rod against the 
chimney, soldered at its lower end to the metal of the roof, and extend: 
ing fifteen or twenty inches above the top of the flue. 
Considerable discussion in late years has taken place in reference to 
the transmission of electricity along a conductor; whether it passes 
through the whole capacity of the rod, or is principally confined to the 
surface. From a series of experiments presented to the American Phi- 
losophical Society, by Professor Henry, on this subject, it appears that 
the electrical discharge passes, or tends 1o pass, principally at the sur- 
face ; and as an ordinary sized house is commonly furnished with from 
two to four perpendicular gutters (generally two in front and two in the: 
rear,) the surface of these will be sufficient to conduct, aneaeys the 
most violent discharge which may fall from the clouds 
3. Electric Conduction; by C. G. Pace, (in a letter to the Eai- 
tors.) —Since my last communication on Electric Conduction, §c. pub- 
lished in your Journal for September, 1846, finding that the merit of 
original observation of the inductive action of atmospheric electricity 
upon extended conductors, has been by some attributed to me, I take 
early opportunity through your indulgence to correct any such impres- 
sion. Your readers by a careful perusal of the paper, will perceive 
that I have introduced the subject, rather incidentally, to prove the 
sensitiveness of the galvanoscope used in the experiments, and that a 
sufficient disclaimer will be found in aconcluding passage, as follows, 
viz: “ During heavy storms a flash of lightning twenty miles distant 
from the wires of Morse’s telegraph, will induce electricity in the wires 
sufficient to operate the magnets and work the telegraph, sometimes 
recording several signals,” an occurrence which has been noticed oc- 
casionally, since the erection of the telegraph in the early part of 1844. 
The merit of prior and original investigation with reference to these 
phenomena, belongs to Prof. Henry ; the results of whose observations 
were published sometime since in the Transactions of the American 
Philosophical Society. The only novelty as far as induction is con- 
cerned in the observations made by myself, is that extraordinary kind 
of disturbance which the needle incurs, under which it will frequently 
move, not as if by sudden impulse, but rather gradually through an 
arc, sometimes of 10°, and there remain for sometime, and then re- 
turn to what may be called its standard position, viz. that which is due 
solely to the influence of the galvanic current. It would appear that 
these changes are due not to sudden discharges of atmospheric elec- 
tricity, but to the passage of clouds or masses of air in différent elec- 
trical states over or near the building. ‘The question then arises, 
the roof of the Sean collect and transmit sufficient electricity to de- 
flect the needle to this extent, or is it due to some other influence. It 
