COMMITTEES ON BEHALF OF THE GOVERNMENT 241 



terms " above proof " and " below proof "; that a special form 

 of hydrometer designed by Wm. G. Tagliabue of New York, 

 be used instead of the ordinary Tralles instrument, and that 

 the Government should test these hydrometers and issue them to 

 the inspectors free of expense. The hydrometers, which were 

 figured in the report of the committee, were to be made in series 

 of five each, so graduated as to cover all percentages from pure 

 alcohol to pure water. The tables which accompanied the report 

 cover 25 pages. They give real and apparent specific gravities 

 and percentages for all mixtures of alcohol and water at different 

 temperatures from zero to 100 Fahrenheit, together with other 

 data of similar character. In addition, the report has appended 

 to it a " Manual for inspectors of spirits," consisting of tables 

 showing the true percentage of proof spirits for and indication 

 of the hydrometer at temperature between o and 100 F., and 

 instructions for their use. This part of the report covers thirty- 

 four pages. 



The committee was not content to restrict its tables to the 

 temperature limits of the earlier ones, but carried on an elaborate 

 series of experiments to ascertain the proper readings of hydrom- 

 eters at temperatures as low as zero Fahrenheit. This was neces- 

 sitated by the fact that spirits were sometimes received at ware- 

 houses in the Northern States in winter time at temperatures far 

 below freezing and often approaching the zero of the Fahrenheit 

 scale. These experiments were carried on, by request of the 

 Treasury Department, at the laboratory of the Surgeon-Gen- 

 eral's Office, and were conducted by Dr. B. F. Craig. 



The committee also considered various forms of hydrometers 

 and decided to recommend one which, in its opinion, was best 

 adapted for the revenue service. Dr. John Torrey and Dr. 

 F. A. P. Barnard made especially accurate mixtures of water 

 and alcohol and prepared and marked a series of delicate floats 

 which were afterwards used by Tagliabue in graduating the 

 hydrometers which he manufactured for the Treasury Depart- 

 ment. 



