TOL. X.] PHILOSOPHICAL TRANSACTIONS. 267 



IV. The College of Physicians Vindicated, and the True State of Physic in 

 this Nation faithfully represented, &c. By Charles Goodall, M. D. London, 

 1676, in 8vo. 



In this vindication of that learned body, the London College of Physicians, 

 their utility to the public and to the profession, i^i suppressing quackery and 

 maintaining the dignity and true interests of the medical character, is strenu- 

 ously advocated. 



Pf the Incalescence of Quicksilver with Gold. By B. R. Communicated in Latin, 

 T Traiislated by Mr. Oldenburg. N° 122, p. 515. 



In this long paper Mr. B. R. enters into an inquiry whether or not the com- 

 mixtion, or amalgamation of gold with mercury, is accompanied with a sensible 

 production of heat ; which he decides in the negative, in respect to common 

 mercury, and in the affirmative with regard to purified, or (as he terms it) ennobled 

 mercury. I took, says he, to one part of the mercury, sometimes half and 

 sometimes an equal weight of refined gold reduced to a calx or subtle powder. 

 This I put into the palm of my left hand, and putting the mercury upon it, 

 stirred it and pressed it a little with the finger of my right hand, by which the 

 two ingredients were easily mingled, and grew not only sensibly but con- 

 siderably hot, and that so quickly, that the incalescence sometimes arrived at 

 its height in a minute. I found the experiment succeed, whether I took as 

 much, or only half as much gold as mercury; but the effect seemed to be much 

 greater when they were employed in equal weight. And to obviate a suspicion, 

 which, though improbable, might possibly arise, as if the immediate contact of 

 the ingredients and the skin produced a sense of heat, which was not due to 

 the action of the metals upon each other; I had the curiosity to keep the mix- 

 ture in a paper, and found not its interposition to hinder me from feeling the 

 incalescence, though it much abated the degree of my sense of it. i" 



I tried also the same mercury with refined silver reduced to a very fine 

 powder ; but I could not perceive any heat or warmth at all ; though I am apt 

 to think, that if I had had a sufficient quantity of leaf-silver to have made the 

 experiment with, I should, after some time, have produced an incalescenccj 

 though much inferior to what the same quantity of mercury would produce with 

 gold. I shall now add, that in order not to be thought to impose upon myself, 

 I not only made trial in my own hand, when in different tempers as to heat and 

 cold, but the hands of others, who were not a little surprised and pleased at the 

 event. And this I did more than once or twice ; by which means I had, and 

 still have, divers witnesses of the truth of the experiment. Among whom is 

 the learned Secretary of the Royal Society ; to whom having given the ingredi- 



M M 2 



