June 15, 1906.] 



SCIENCE. 



911 



tion by placing them in a confined space in 

 which there is exposed a large surface of a 

 saturated solution of sodium nitrate. 



The following table gives the results of 

 experiments upon Virginia fire-cured 

 tobacco using the same solutions as had 

 been used for the experiments upon cigar 

 tobaccos. 



Table VII. 

 Change in loeight and condition of Virginia fire- 

 cured tobacco. 



Originally this tobacco was in a very wet 

 condition and it was expected that the 

 sample in the best condition would suffer 

 a great loss in weight, and this is actually 

 what happened. The atmosphere in con- 

 tact with this tobacco must be very much 

 drier than that in contact with any of the 

 cigar tobaccos, and the solution which pre- 

 serves this tobacco in good condition is a 

 little less concentrated than the acid which 

 kept (Old Gold) plug-cut tobacco in the 

 same condition as it was when taken from 

 the box. 



It will be observed that different tobaccos 

 require vastly different treatments to bring 

 them to the proper moisture condition for 

 manufacture or consumption. This work, 

 however, brings out certain generalizations. 

 All cigar tobaccos, whether filler, wrapper 



or binder, previous to manufacture require, 

 within certain limits, very much the same 

 treatment, i. e., they are brought to the 

 proper physical condition for manufacture 

 by remaining a few days in an atmosphere 

 which has acquired the concentration of 

 water vapor, which is given off by a satu- 

 rated solution of ammonium sulphate or of 

 potassium nitrate. The second generaliza- 

 tion is that all tobaccos, whether cigar or 

 pipe, can be brought into proper physical 

 condition for consumption by remaining a 

 few days in an atmosphere which has ac- 

 quired the concentration of water vapor 

 given off by a saturated solution of sodium 

 nitrate or some salt whose saturated solu- 

 tion gives approximately the same vapor 

 pressure. 



The principles enunciated in this paper 

 might also be employed for the keeping of 

 paper and other absorbent materials M'hose 

 physical condition is affected by humidity. 



SUMMARY. ' "''i -^ 



1. It has been pointed out that the pres- 

 ent methods for keeping tobaccos in proper 

 condition for use, and for bringing them 

 to the proper condition are haphazard and 

 unsatisfactory. 



2. Solutions have been found which keep 

 tobaccos in the required condition for man- 

 ufacture and use. This method is auto- 

 matic, for the composition of a solution, 

 containing some of the solid salt, does not 

 change upon evaporation or condensation 

 of moisture, until all the water has evapo- 

 rated from the solution, or until all the 

 solid has been dissolved by condensed mois- 

 ture. The solutions which have been pro- 

 posed will not only preserve a proper de- 

 gree of moisture, but will also bring wet or 

 dry tobaccos into a proper moisture condi- 

 tion. The solutions which have been pro- 

 posed are quite inexpensive. 



3. Practical tests have been made of the 



