Bibliography. 393 



of shocks for medical purposes, for exhibiting the decomposition of 

 water, furnishing the elements oxygen and hydrogen at their respective 

 poles, and producing definite electro-chemical results. These two last 

 results could not be obtained without the aid of the unitress. But, with 

 this improvement, the instrument was still wanting in one property of 

 the galvanic battery — viz. that property which chemists call quantity, or 

 that power upon which depends its ability to magnetize, and also to heat 

 platinum wires. This last property has been given to the machine by 

 the recent contrivance of Prof. Page. The machine, in its novel con- 

 struction under his improvement, developed what is called, by way of 

 distinction, the current of intensity, but had a very feeble magnetizing 

 power. By a peculiar contrivance of the coils, (not to be made public 

 until his rights are in some way secured,) the current of quantity is ob- 

 tained in its maximum, while, at the same time, the intensity is so much 

 diminished that it gives scarcely any shock, and decomposes feebly. It 

 has been successfully tried with the magnetic telegraph of Prof. Morse, 

 and operates equally well with the battery. It affords, by simply turn- 

 ing a crank attached to the machine, a constant current of galvanic 

 electricity ; and as there is no consumption of material necessary to 

 obtain this power, it will doubtless supersede the use of the galvanic 

 battery, which, in the event of constant employment, would be very 

 expensive, from the waste of zinc, platinum, acids, mercury, and 

 other materials used in its construction. It particularly recommends 

 itself for magnetizing purposes, as it requires no knowledge of chem- 

 istry to insure the result, being merely mechanical in its action, and 

 is always ready for action without previous preparation ; the turning 

 of a crank being the only requisite when the machine is in order. 

 It is not liable to get out of order ; does not diminish perceptibly in 

 power when in constant use, and actually gains power when stand- 

 ing at rest. It will be particularly gratifying to the man of science, 

 as it enables him to have always at hand a constant power for the 

 investigation of its properties, without any labor of preparation. We 

 notice among the beautiful results of this machine, that it charges an 

 electro-magnet so as to sustain a weight of one thousand pounds, and 

 it ignites to a white heat large platinum wires, and may be used suc- 

 cessfully for blasting at a distance ; and should government ever adopt 

 any such system of defence as to need the galvanic power, it must super- 

 sede the battery in that case. Prof. Page demonstrates, by mathemat- 

 ical reasoning, that the new contrivance of the coils affords the very 

 maximum of quantity to be obtained by magnetic excitation." 



2. Final Report on the Geology and Mineralogy of the State of 

 New Hampshire, with Contriiutions towards the Improvement of Agri' 



