162 NATURAL HISTORY. 



prepared metal for the version, for that will facilitate 

 the work. The sixth is, that you give time enough 

 for the work ; not to prolong hopes, as the alchemists 

 do, hut indeed to give nature a convenient space to 

 work in. These principles are most certain and true ; 

 we will now derive a direction of trial out of them, 

 which may, perhaps, by further meditation, be 

 improved. 



327. Let there be a small furnace made of a tem 

 perate heat ; let the heat be such as may keep the 

 metal perpetually molten, and no more ; for that 

 above all importeth to the work. For the material, 

 take silver, which is the metal that in nature sym- 

 bolizeth most with gold ; put in also with the silver, 

 a tenth part of quicksilver, and a twelfth part of 

 nitre, by weight ; both these to quicken and open the 

 body of the metal ; and so let the work be continued 

 by the space of six months at the least. I wish also, 

 that there be at sometimes an injection of some oiled 

 substance, such as they use in the recovering of gold, 

 which by vexing with separations hath been made 

 churlish ; and this is to lay the parts more close and 

 smooth, which is the main work. For gold, as we 

 see, is the closest, and therefore the heaviest of 

 metals ; and is likewise the most flexible and tensi- 

 ble. Note, that to think to make gold of quick 

 silver, because it is the heaviest, is a thing not to be 

 hoped ; for quicksilver will not indure the manage 

 of the fire. Next to silver, I think copper were 

 fittest to be the material. 



