4S6 
Scientific Intelligence, 
the magnetic minerals which it contains, and which should be con- 
sidered as so many voltaic piles. The elevation of temperature which 
takes place in the conductors of electric currents, ought also to 
take place in those of the terrestrial globe. Is not this the 
cause of that internal heat in the earth, which has been establish- 
ed by recent observations ? And when we consider that this ele- 
vation of temperature produces, when the current is sufficiently 
energetic, a permanent incandescence, accompanied with the most 
brilliant light, without combustion or loss of substance, may we 
not conclude that opaque globes are so, on account of the little 
energy of the electrical currents which are established in them, 
while those that shine by themselves, derive their light from the 
more active currents which they possess ?” 
15. Mr Lecounfs Method of finding the Dip qfHhe Needle,^ 
In order to measure the dip at sea, Mr Lecount mounts a bar 
of iron free of magnetism, and about 2 feet long, and upon a stand 
furnished with a divided quadrant and spirit-level, all the parts 
of which are either of brass or copper. The stand is then to be 
placed north and south, and upon a horizontal plane, as ascer- 
tained by the level ; and, by means of a delicate compass, the bar 
is examined in different positions, till one side of it is found to 
be all one pole, and the other side all a contrary pole, and 
the ends neutral. The divisions on the arc will then give the dip 
of the needle. — Lecount’s Description of the Changeable Mag- 
netic properties possessed hy all Iron bodies, &c. p. 53. Lond. 
1820. 
16. Aecount of two large Loadstones. — In a paper giving an ac^ 
count of three large loadstones brought from Moscow, read before 
the Wernerian Society on 10th March last, Mr JohnDeuchar gives 
the following notice regarding two of them : The largest load- 
stone weighs 125^ pounds ; and it measures in length 10| inches, 
in breadth 8J, and in height inches. When I received it, it 
could carry 163 pounds ; but, by gradually increasing the 
weight, I afterwards brought it to' support 165 pounds, exclu- 
sive of a connecting iron of about 28 pounds, and several supports, 
which might be 12 pounds more ; thus giving an improved power 
equal to 42 pounds. The weight of the second loadstone had 
not been taken previous to fitting on the armature, but it is 
* Tills loadstone is now in the possession of Dr Hope. — E d. 
