f 



354 Miscellanies, 



second pole existing some where in tliat neighborhood. Captain 

 Parry was engaged, at the same period^ near the other magnetic pole 

 in the north. 



Proportion of rain at different heights in the air. — Prof. Phil- 

 lips has ascertained, that as you ascend, the qu'antity of rain increas- 



- X ^ ooi — 



one on the top, one on the ground, and one midway. 



M 



Elect 



Mr. Snow Harris, in opposi- 

 tion to the idea that electricity is retained in excited bodies by the 

 air which surrounds them, stated that he had succeeded in retaining 

 the electrical charge, for some days, upon a brass ball enclosed in a 

 vacuum, so perfect that the air pump guage showed the exhaustion 

 to be two hundred and ninety nine parts in three hundred; an elec- 

 trometer, connected with this ball, showed an almost unimpaired de- 

 gree of divergence, for more than twenty four hours. This state- 

 ment has been confirmed by an eminent practical philosopher in 

 London. 



Galvanic machine. — In this Journal, Vol. xx, p. 340, may be 

 seen a drawing and description, by Mr. now Prof. Joseph Henry, 

 of a galvanic machine, invented by him, which is upon exactly the 

 same principles as the one described below. Prof. Henry's inven- 

 tion is long prior to those w^hich in different countries have claimed 

 this discovery. 



The Rev. Mr. Ganby exhibited the working model of a machine, 

 for producing moving power, by the application of electro-magnetic 

 influence. The model consisted of a pendulum, the lower part of 

 which was a magnet, placed with its poles opposite to the ends of 

 two horse shoe bars of soft iron, around which were coiled helices 

 of wire, so arranged that by the end of the helices dipping Into 

 cups of mercury, the poles of a simple galvanic battery could be al- 

 ternately made to communicate with the cups in one order, and the 

 next instant the machine reversed that order, by means of a system 

 of bent wires, caused to vibrate upon an axis, the ends of these bent 

 wires alternately dipping into one pair of cups and the next vibration 

 into another; by these means, the soft iron horse shoes are at one 

 instant a magnet, with the poles in one order, the pendulum being 

 then attracted towards both these poles ; but the next instant, the 

 poles being reversed, the pendulum is thrown forcibly back, while 

 the opposite soft iron horse shoe is now a magnet, ready to attract 



It ; then again it is thrown back from this second temporary magnet, 



