362 NOVUM ORGANUM. 



such as are quite spongy, hollow, and in great part filled with air) does 

 not exceed the ratio of one to twenty-one; so limited is Nature, or at 

 least that part of it of which it is our business principally to deal. 



We have also thought it worth while to try whether it is possible to 

 find the ratios borne by non-tangible or pneumatic bodies to tangible 

 ones. This we have attempted by the aid of the following contrivance. 

 We took a glass phial, capable of containing about an ounce, using a 

 vessel of small size, that the subsequent evaporation might be pro 

 duced by a smaller expenditure of heat. This phial we filled nearly 

 to the neck with spirit of wine ; choosing spirit of wine because, by the 

 above-mentioned table, we observed that it was the rarest of those 

 tangible bodies which arc compact and not hollow, and that it con 

 tained the least matter for the space it filled. Then&quot; we noted carefully 

 the weight of the spirit with the phial. Afterwards we took a bladder, 

 holding about two pints ; from it we pressed out all the air possible, until 

 both sides of the bladder met. We first rubbed the bladder over gently 

 with oil, to make it air-tight, the oil stopping up whatever pores it had. 

 We next tied the bladder tightly about the mouth of the phial, with a 

 thread waxed to make it stick better and bind more closely, the mouth 

 of the phial fitting inside that of the bladder. We then placed the 

 phial over burning coals in a fireplace. After a while, the vapour or 

 breath of the spirit of wine expanded, and became changed into 

 vapour by the heat, gradually inflating the bladder, and dilating it in 

 all directions like a sail. As soon as this took place, we removed the 

 glass from the fire, and placed it on a carpet, that it might not crack 

 with the cold ; and at once made a hole in the top of the bladder, to 

 prevent the vapour from returning into liquid on the cessation of the 

 heat, and so confusing our calculations. We then removed the 

 bladder itself, and again took the weight of the spirit of wine which 

 remained. Thence we computed how much had been consumed in 

 producing vapour or air, and comparing the space which the body had 

 filled when it was in the state of spirit of wine in the phial with that 

 which it occupied after it had become pneumatic in the bladder, we 

 ascertained the ratios ; from which it was quite clear that the body so 

 turned and changed had expanded into a bulk an hundred times greater 

 than it had filled before. 



In like manner let the Nature inquired into be Heat or Cold, so weak 

 in degree as not to be perceptible to the senses. These are brought 

 within reach of the senses by a heat-glass, such as we have described 

 above. For heat and cold are not themselves perceptible to the touch ; 

 but heat expands air, cold contracts it. Nor again is that expansion 

 and contraction of the air perceptible to the sight, but the expansion 

 of the air depresses the water ; its contraction elevates it, and so, at 

 last, is brought under the cognisance of the sight ; not before, nor 

 otherwise. 



In like manner let the Nature inquired into be the Mixture of 

 Bodies, viz. what of water, oil, spirit, ashes, salts, and the like, they 

 contain ; or, as a particular Instance, how much butter, curd, serum, 

 and the like, there is in milk, These mixtures are brought within 



