Description of the model of an Electro-Magnetic Engine. 313 



may be considered as similar to that of a number of wires wound 

 in the same direction, whose surface is equal to that of the ribbon. 

 The labor of constructing a magnet of any size upon the old plan, 

 by winding an iron with a number of wires, is very great, but a mag- 

 net constructed upon the plan mentioned above may be made in a 

 few hours. 



The expense of construction is also vastly diminished, and this, 

 not only by diminishing the labor, but also the cost of materials. 

 And as the power of the magnet may be increased to an unhmited 

 extent, it must be preferable in every respect to those constructed 

 with wires. 



Art. XI. — Description of the model of an Electro-Magnetic En- 

 gine, constructed by John B. Zabriskie, M. D. 



The facility with which the poles of an electro-dynamic magnet 

 may be changed by reversing the electric current passing around it, 

 first suggested the construction of electro-magnetic engines. The 

 first apparatus constructed upon this principle was made by Prof. 

 Henry, who gave a vibratory motion to a magnet to which were at- 

 tached two bent wires alternately dipping in two cups of mercury on 

 each side. 



Some time since I constructed a model of an engine upon this 

 principle, of which the following is a description. 



A, B, is a large compound magnet, composed of sixteen bars of 

 steel, each one quarter of an inch in thickness and two feet long, 

 magnetized separately, and combined into one magnet. This has 

 an alternating motion upon an axis between the poles of two horse 

 shoe galvanic magnets, constructed upon the principle mentioned in 

 the preceding article. 



These magnets C E D, F H G, are composed each of a horse 

 shoe of soft iron, twenty four inches long, and one inch in diameter, 

 wound with a zinc ribbon one inch in width, and one hundred and 

 twenty feet long. 



N, is a rod turning a crank which moves the fly-wheel P. O, is 

 a rod having two pins projecting from it which moves a lever attach- 

 ed to a bascule, which for the sake of distinctness is not represented 

 in this figure but may be seen below. This is composed of a piece 

 of mahogany pierced with four holes, two of which are oblong, and 



Vol. XXXII.— No. 2. 40 



