194 Miscellanies. 
this particular disposition of the metals which compose the aneyey 
eléctromotor. 
The surprising effect of Wollaston’s miniature battery as well as 
those of Children’s great battery which were not proportioned to the 
metallic surface of the battery are explained by these results.—Jdem. 
9. Magnetic Experiments—Mr. Kupffer in a letter to Sir D. 
Brewster, announces that he has found, that the intensity of magnetic 
forces, i in ia bars, diminishes as much by the action of cold as by 
that of hea 
To ae magnetic cylinders, of constant power, to measure the 
intensity of the magnetism of the earth, he not only plunges thenr 
many times into boiling water, but cools them as often to 20° or 25°, 
below zero, of Reaumur. 
Mr. K. has proved by a direct method, the existence of a daily 
variation in the dip of the magnetic needle, and in the intensity of 
the earth’s magnetism—the latter, by observing, each day, the extent 
and duration of the oscillations of a needle of a large dip and suspended 
upon the edge of a knife. 
He found that the dip was greater by some minutes at eleven A. M. 
than at eleven P. M. and that the intensity of the earth’s magnetism 
is much greater at night than in the morning.—Phil. Mag. March, 
1832 
10. Phenomenon presented by the breaking of a Prince Rupert's 
drop.—M. Bellani has observed that in breaking the tip of a Prince — 
Rupert’s drop, under the water contained in a glass receiver, the lat- 
ter is broken with an explosion, at the very moment and even when 
the surface of the water is uncovered. He attributed this effect to 
the rapidity with which the drop is broken and to the consequent ex- 
pansion, so great that the water has not time to yield, but com- 
municates, like a solid body, the motion to the sides of the receiver. 
This phenomenon is similar. to that which occurs when a ball is 
discharged from a pistol upon the surface of water—the ball is com- 
pressed and flattened as it would be if fired against a solid sig _ 
Bib. Univ. Feb. 1833. 
PHYSICAL GEOGRAPHY. 
a Spowting fountain of mineral water, diseovered in 1832, near 
Cape Uneino, kingdom of Naples, by M. J. Auldjo.—Bubbles of 
of air were long since observed to-rise trom the bottom of the water 
