594 Transactioits of the American Institute. 



on the principle that the actual energy of mechanical force, con- 

 jointly with the potential energy of the magnet, can develop a greater 

 amount of potential energy than is originally resident in the mag- 

 net; in other words, it is a method of converting a part of the 

 actual energy of the prime mover into the potential energy of mag- 

 netism. 



TIN-LINED LEAD PIPE. 



The Chairman said he had lately visited the works of Messrs. Col- 

 Tvell, Shaw & Willard, manufacturers of the tin-lined lead pipe, 

 and, in company with many well-known engineers and scientific 

 gentlemen, had witnessed a scries of experiments made with ordi- 

 nary lead pipe, and with tin-lined lead pipe, to ascertain the 

 internal pressure at which each would give way. Five sections of 

 each kind of, pipe were tested by hydraulic pressure. The result 

 of these experiments may be briefly stated: It was found that tin- 

 lined pipe of a given weight stood about one-seventh more pres- 

 sure than pure lead pipe of the same internal diameter and of twice 

 the weight. 



An interesting discussion followed, on the eflTects of using lead 

 pipe. It was stated that almost every young mau in a certain 

 village in Connecticut, had the rheumatism, while, in a neighboring 

 village, this disease wtis not prevalent. This difference was accounted 

 for by the fact that, in the first-named village the water used all 

 came through lead pipe. 



Dr. J. W. Richards expressed the belief that the use of lead 

 pipe to convey some drinking waters, would produce such an effect. 



Dr. J. E. Snodgrass spoke of the evils which result from using 

 Croton water, after passing through long lengths of lead pipe. 



Prof. Vanderweyde said, all constitutions are not affected alike; 

 many would not experience any bad effects from using water drawn 

 from lead pipes. Plumbers, in repairing the lead tanks used in 

 oil of vitriol factories, generally feel the effects of lead poison. He 

 had tested the water from the lead-lined tank which supplies the 

 Cooper Union, and had not been able to detect any traces of lead. 



Dr. D. D. Parmelee remarked, that he had noticed, last summer, 

 that at one place in Poughkeepsie, ale was drawn through forty 

 feet of lead pipe. He thought such ale, at least, must be the source 

 of much evil. 



Prof. Vanderweyde said lead pipe, through which oil is drawn, 

 lasts but three or four years. The question is, where djoes all tho 

 lead go to? 



