394 Miscellanies. 



it never had continued to run over ten days at a time. He had re- 

 peatedly taken it up and tried it, supposing it contained a leak. He 

 called on the man whom he had originally employed to lay liis pipe, 

 for a cause, and found that he knew nothing, except that the stoppage 

 was occasioned by air, and that air could not get in, unless there was 

 a leak in the pipe. My friend, when I arrived, was taking up his 

 pipe for the last time, to try whether there was a leak. After trying 

 it with a pressure of 50 lbs. to the inch, he found no leak and laid 

 down his pipe, and by means of a forcing pump set the water running 

 again. As formerly, after running less and less for about ten days, it 

 entirely ceased. I then took it in hand, determined to find out, if 

 possible, the cause of the obstruction. I made a puncture in the pipe 

 at one of the high places lower than the spring, and found that the 

 pipe contained not air, but hydrogen gas. I was now more embarras- 

 sed than before, as I could not imagine what was the source of the hy- 

 drogen. I happened about that time to take a tin cup of water, and 

 noticed a row of minute bubbles along the seam ; the thought struck 

 me, that it was the combination of metals in the pipe that occasioned 

 galvanic action sufficiently powerful gradually to decompose the water. 



To try it, I put a small piece of the same pipe into a tumbler of 

 water, and after standing two days, I found the pipe covered with a 

 coat of white oxide, with the exception of the seam where it was 

 soldered together, and there the tin which composed the solder was 

 perfectly bright. From this I inferred, that the galvanic action of the 

 pipe on the water produced decomposition, the oxygen combining 

 with the lead, and the hydrogen carried along by the water until it 

 came to the high places in the pipe, and there accumulated until it 

 filled the pipe and entirely obstructed the water. 



To remedy this difficulty, I made holes into the pipe at every high 

 place, and soldered over them a vertical tube, open at the top, excep- 

 ting the hill that was higher than the spring, and to that part of the 

 pipe I soldered a tube similar to the others, with this exception, that I 

 soldered it up at the top. The first mentioned tubes let the gas escape 

 as it came along, and the one on the highest elevation suffered the gas 

 to accumulate in it until a small bubble protruded below the end of 

 the vertical tube, and was detached from the body of the gas in the 

 tube and carried on by the water. After the above arrangement was 

 effected, the water was set running, and has continued to run without 

 any sensible diminution ever since, upwards of eight months. Query. 

 Is not the action of water upon lead, mentioned in Vol. xxxiv, p. 25, 

 of this Journal, occasioned by a combination of some other metal with 

 the lead 1 



Tuscaloosa, Ala. May 25th, 1838. 



