states. He maintained, that the recession, or apparent repulsion, of bodies equally electrified, is caused by attraction; and he supported his opinion by reasoning of this nature:

с

b

a

b

с

d

In the preceding figure, let 1, 2, 3, 4, be four pith balls equally electrified; and let a, b, c, d, be the four strata of air surrounding them. The air between the balls quickly becomes as highly electrified as they are. The balls have a tendency to get rid of their electricity; and the only way they can do so would be to part with it to the surrounding strata of air. Therefore, the recession of bodies positively electrified in an equal degree, is caused by their being attracted

by the surrounding air; or, if negatively, by the surrounding air attracting them. Therefore no recession takes place in an exhausted receiver. The lecturer stated that electricity was repulsive only to its own particles when in a condensed state. He then explained electricity by induction, and concluded by making some observations on electrical light. He shewed the electrical spark, its zigzag appearance, and detailed some experiments with it, when it had been passed through conductors of great length. He then discharged a cannon, loaded with hydrogen and atmospheric air, by a spark from his finger, when standing on the stool; also some ether; and finished by exhibiting many beautiful devices, caused by sending a spark through a circuit of pieces of tinfoil.

The third lecture was devoted to the Leyden phial. After stating the theory, he performed a number of experiments, to establish it. They were satisfactory. He shewed an electric bird, which flew between two balls connected with the inside and outside of a large phial. On the same principle he made two little figures play This sketch explains the kind of

at see-saw.

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apparatus, though I cannot vouch for its being exactly like that used by the president.

The one figure takes the electricity from the inside, and the other conveys it to the outside; or, vice versâ, if the electric fluid is negative. Of course, they are perfectly insulated. The jar was a very large one, and the apparatus kept going for a long time.

The lecturer then explained the Electrophorus; for an account of which I refer to Dr. Roget.5 The lecturer concluded by adverting to medical electricity. On this point, time forced him to be

brief. He made, however, some curious statements of its beneficial effects in rheumatic gout, paralysis, chilblains, &c. A poor woman came to a friend of his, in the country, complaining that she could not make her hand obey her: it would pull her head, tear her clothes, and, she added, "I know not how to help it." The electric fluid effectually cured the unruly member. He recommends the patient to be electrified on the stool, and the attractor, or director, to be drawn over the part affected for some time, always down the system. Shocks should very seldom be used, and then only very weak ones. He shewed a small machine adapted to this purpose.

In this lecture the construction of the electrical battery was explained, and its effects on various bodies shewn. It rendered oranges and eggs luminous; and loaf-sugar gave out a phosphorescent light, continuing for some time, when placed in the circuit of the charge; resin and sulphur inflamed; profiles were formed of oxide of gold; silver, iron, and steel wires, were fused and thrown off in a shower of red-hot globules. The same effect took place under water. An account was given of the torpedo and gymnotus,

and of the manner of catching the latter with horses. In conclusion, the subject of electromagnetism was adverted to; its more full consideration being reserved for the Curator. Needles were rendered permanently magnetic by the circulation of the electrical fluid-magnetic poles were destroyed and reversed. In this department our lecturer has made some discoveries.

The fifth lecture was, perhaps, the most interesting of all, being devoted to the subject of Atmospheric Electricity. The room was well attended, and, with one exception, the experiments succeeded well. He began by adverting to the subject generally, and to the means used for investigating the electricity of the atmosphere. He gave an interesting account of the means by which Dr. Franklin proved the identity of lightning and electricity, and exhibited a compact electrical kite. This differed, in many respects, from the common kite: it was made of linen or light stuff of some kind, was square, and stretched by two pieces of bamboo or cane, and it had no tassels. The string had some metallic threads interwoven with it, and was fixed on a roller with a winch. The whole appa