54 NATURAL HISTORY. 



doth good ; because by little and little it openeth the 

 pores, without any sudden working upon the spirits. 

 This experiment may be transferred unto the cure of 

 gangrenes, either coming of themselves, or induced by 

 too much applying of opiates ; wherein you must 

 beware of dry heat, and resort to things that are 

 refrigerant, with an inward warmth and virtue of 



o 



cherishing. 



Experiment solitary touching weight. 



789. Weigh iron and aqua fortis severally ; then 

 dissolve the iron in the aqua fortis, and weigh the 

 dissolution; and you shall find it to bear as good 

 weight as the bodies did severally ; notwithstanding 

 a good deal of waste by a thick vapour that issueth 

 during the working ; which sheweth that the opening 

 of a body doth increase the weight. This was tried 

 once or twice, but I know not whether there were any 

 error in the trial. 



Experiment solitary touching the super-natation of 

 bodies. 



790. Take of aqua fortis two ounces, of quicksilver 

 two drachms (for that charge the aqua fortis will 

 bear) ; the dissolution will not bear a flint as big as 

 a nutmeg : yet (no doubt) the increasing of the weight 

 of water will increase his power of bearing; as we see 

 brine, when it is salt enough, will bear an egg. And 

 I remember well a physician, that used to give some 

 mineral baths for the gout, &c. ; and the body, when 

 it was put into the bath, could not get down so easily 

 as in ordinary water. But it seerneth the weight of 

 the quicksilver more than the weight of a stone, doth 



