362 WRITINGS OF JOSEPH HENRY. [1855 



I accepted the proffered co-operation of Professor George C. 

 SchseflFer, of the Patent Office, and directed the putting up of 

 the necessary apparatus in one of the towers of the Smith- 

 sonian building. The determination of the density of the 

 liquid, and the details of the experiments, were intrusted to 

 Professor Schaeffer, to whom I am also indebted for the 

 following account of the process employed and the results 

 obtained. 



As the successful experiment was said to have been made 

 with a column of liquid nearly one hundred feet high, and 

 as the pressure of such a column was given as the cause of 

 the separation of the water or alcohol from the mixture, the 

 repetition of the experiment should be on a corresponding 

 scale. 



The great tower of the Institution building was already 

 fitted for experiments requiring like conveniences. A well, 

 or series of openings giving a height of over one hundred 

 feet, passing through several stories was the place selected. 

 A series of stout iron tubes of about an inch and a half in 

 internal diameter formed the column, the total length of 

 which was one hundred and six feet. Four stop-cocks were 

 provided, one at bottom, one about four feet from the top^ 

 and the other two to divide the interval equally or nearly so. 



The liquor used was common rye whiskey of 44 per cent, 

 at 60° Fahr., and of 44 on the United States Revenue hy- 

 drometer, one of which was used in testing the liquor. 



The experiment commenced on the 18th of November, 

 1854; a leak occurring caused the trial to be limited to the 

 lower thirty feet, after the lapse of a few hours. On the 20th 

 the tube was refilled, and after testing at intervals of a few 

 days, the loss was supplied, the whole apparatus, with each 

 cock and the top sealed up, was left to itself until December 

 14th, when it was again tried at each cock. With a slightly 

 diminished quantity, about one hundred feet in height, the 

 whole again stood until the 18th of April, 1855, when the 

 tests were again made. 



Fortunately for the result, the original liquor had been 

 repeatedly tested at different temperatures; the contents of 



