PHILOSOPHICAL SOCIETY OF WASHINGTON. 243 



thronj^li fill the series, the whole will form a continued coil of 

 one lung wire. By soldering different ends the whole may be 

 formed into a double coil of half the length, or into a triple coil 

 of one-third the length, etc. The horse-shoe was suspended in 

 a rectangular wooden frame 3 feet 9 inches high and 20 inches 

 wide." 



Two of the wires (one from each extremity of the legs) being 

 joined together by soldering, so as to form a single circuit of 

 120 feet, with its extreme ends connected with the battery, pro- 

 duced a lifting power of 60 pounds. {Ex. 19.) The same two 

 wires being separately connected with the same battery (forming 

 a double circuit of 60 feet each) a lifting power of 200 pounds 

 was obtained: {Ex. 10.) or more than three times the power of 

 the former case with the same wire. Four wires (two from each 

 extremity of the legs) being separately connected with the bat- 

 tery, (forming four circuits,) gave a lifting power of 500 pounds. 

 {Ex. 12.) Six wires (three from each leg) united in three pairs, 

 (forming three circuits of 120 feet each,) gave a lifting power of 

 290 pounds. {Ex. 18.) The same six wires being separately 

 connected with the battery in six independent circuits, produced 

 a lifting power of 570 pounds : {Ex. 13.) or very nearly double 

 that of the same wires in double lengths. When all the nine 

 wires were separately attached to the battery, a lifting power of 

 650 pounds was evoked. {Ex. 14.) In all these experiments 

 "a small single battery was used consisting of two concentric 

 copper cylinders, with zinc between them : the whole amount of 

 zinc surface exposed to the acid from both sides of the zinc was 

 two-fifths of a square foot : the battery required only half a pint 

 of dilute acid for its submersion." 



"In order to ascertain the effect of a very small galvanic ele- 

 ment on this large quantity of iron, a pair of plates exactly one 

 inch square, was attached to all the wires : the weight lifted was 

 85 pounds." {Ex. 16.) This was certainly a very remarkable 

 result; particularly when compared with Moll's 75 pounds with 

 eleven square feet of zinc. In order to obtain the maximum 

 attractive power of this magnet, with its nine coils, "a small 

 battery formed with a plate of zinc 12 inches long and 6 wide, 

 and surrounded by copper, was substituted for the galvanic 

 element used in the former experiments : the weight lifted in 

 this case was 750 pounds." {Ex. 15.) This is exactly ten times 

 the maximum weight supported by Moll's magnet with a far 

 greater battery power. In illustration of the feeble power of the 

 magnetic poles when exerted separately, it was found that with 

 precisely the same arrangements giving a holding power of 750 

 pounds to the double contact armature, — either pole alone was 

 capable of sustaining only 5 or 6 pounds : "and in this case we 

 never succeeded iu making it lift the armature — weighing 7 



17 



