212 PHYSIOLOGICAL REMAIN*. 



have observed little of them, neither of toughness 

 nor brittleness. 



11. The degrees of fixation and volatility lac- 

 knowledge, except the two utmost, which never 

 were observed. 



1 2. The question of transmutation is very doubt 

 ful. Wherefore I refer your honour to the fourth 

 tome of &quot; Theatrum Chymicum :&quot; and there, to that 

 tract which is intitled &quot; Disquisitio Heliana ;&quot; where 

 you shall find full satisfaction. 



The fourth letter of the cross-row, touching restitution. 



FIRST, therefore, it is to be inquired in the nega 

 tive, what bodies will never return, either by their 

 extreme fixings, as in some vitrifications, or by ex 

 treme volatility. 



It is also to be inquired of the two means of 

 reduction ; and first by the fire, which is but by con 

 gregation of homogeneal parts. 



The second is, by drawing them down by some 

 body that hath consent with them. As iron draweth 

 down copper in water ; gold draweth quicksilver in 

 vapour ; whatsoever is of this kind, is very diligently 

 to be inquired. 



Also it is to be inquired what time, or age, will 

 reduce without help of fire or body. 



Also it is to be inquired what gives impediment 

 to union or restitution, which is sometimes called 

 mortification ; as when quicksilver is mortified with 

 turpentine, spittle, or butter. 



