144 PHENOMENA OF THE UNIVERSE. 



straight necked without any lip, (for then the vapour of 

 the water would distil more rapidly, and the dew would 

 glide down that part of the bladder which was joined to 

 the neck of the phial) but with the neck at first straightened 

 a little, and then returned as it were with the lip. This 

 vessel I half filled with water, (supposing that this would 

 hasten the boiling) and took the weight of the water with 

 the phial itself by sand put in the scale of a balance. Then 

 I took the bladder which might contain about half a pint, 

 taking care that it should be neither old nor dry and given 

 to resist more from dryness, but new and rather soft. I then 

 tried the soundness of the bladder by blowing, to be certain 

 that there were no holes in it, and then emptied all the air 

 out of it as much as possible. I also first of all applied oil 

 to the outside of the bladder, and made it take the oil by 

 rubbing it in. This I did to make the bladder closer and to 

 stop up the pores (if there might chance to be any) with 

 the oil. I fastened the bladder securely about the mouth 

 of the phial, the mouth of the phial being received into the 

 mouth of the bladder ; this was done with a string waxed 

 a little that it might adhere better and tie more closely. 

 But this is made better by clay made out of meal and the 

 white of an egg, and bound with black paper and well dried, 

 as I myself have found. At last I placed the phial over 

 burning coals on a little hearth. The water soon after 

 began to boil, and by degress to inflate every part of the 

 bladder, till it seemed as though it would break. I imme 

 diately removed the glass from the fire and placed it upon 

 the carpet, lest the glass should be broken by the cold, and 

 instantly I made a little hole at the top of the bladder with 

 a needle, lest on the vapour being restored to water at the 

 ceasing of the heat, should fall back and confound the 

 ratios. But afterward I took away the bladder itself with the 

 string, and cleared it from the clay, if any had been used, 

 and then weighed the remaining water with the phials 

 again. And I found that about the weight of two penny 

 weights had been consumed. And I saw that whatever of 

 the body had filled the bladder when it was full of wind, 

 was made and produced from that which had been lost from 

 the water. The matter, therefore, when it was contracted 

 in the body of the water, filled as much space as two penny 

 weights of the body of water filled : but the same matter 

 expanded in a body of vapour filled half a pint. I there 

 fore set down the ratios according to the dimension ex 

 pressed in the table : a vapour of water can bear a ratio of 



