io An Inquiry concerning 



ceive what that cause could possibly be, unless it were 

 either a greater quantity of moisture attached to the 

 external surface of the bottle which contained the water 

 than to the surface of that containing the spirits of 

 wine, or some vertical current or currents of air caused 

 by the bottles, or one of them not being exactly of the 

 temperature of the surrounding atmosphere. 



Though I had foreseen, and, as I thought, guarded 

 sufficiently against, these accidents, by making use of 

 bottles of the same size and form, and which were blown 

 of the same kind of glass and at the same time, and 

 by suffering the bottles in the experiments to remain 

 for so considerable a length of time exposed to the dif- 

 ferent degrees of heat and of cold which alternately 

 they were made to acquire; yet, as I did not know the 

 relative conducting powers of ice and of spirit of wine 

 with respect to heat, or, in other words, the degrees 

 'of facility or difficulty with which they acquire the tem- 

 perature of the medium in which they are exposed, 

 or the time taken up in that operation, and, conse- 

 quently, was not absolutely certain as to the equality 

 of the temperatures of the contents of the bottles at 

 the time when their weights were compared, I deter- 

 mined now to repeat the experiments, with such va- 

 riations as should put the matter in question out of all 

 doubt. 



I was the more anxious to assure myself of the real 

 temperatures of the bottles and their contents, as any 

 difference in their temperatures might vitiate the ex- 

 periment, not only by causing unequal currents in 

 the air, but also by causing, at the same time, a greater 

 or less quantity of moisture to remain attached to the 

 glass. 



