QgO PHILOSOPHICAL TRANSACTIONS. [aNNO I763. 



the sand must certainly contain a very considerable quantity of iron, and there- 

 fore determined to make trial of it. He was however, for some time, inter- 

 rupted in his design, by information he received from a friend, that such an in- 

 quiry had been made many years before, by a member of the h. s., and of che- 

 mical knowledge, but without success; and that the experiments were published 

 in the Phil. Trans., vol. xvii, p. 624.* 



Having thoroughly considered those experiments, they appeared to Mr. H. far 

 from decisive, and that if Dr. Moulin had placed more confidence in the power 

 of the magnet, and less in his menstruums, he would rather have concluded that 

 there might be some sorts of iron ore which his menstruums would not touch in 

 the moist way, nor any regulus be produced from them in the dr)', as he made 

 use of them, which yet might, under some other hands, be subdued by more 

 apt and powerful methods than any which at that time he was acquainted with. 



Mr. H. however apprehended he might draw this conclusion from his experi- 

 ments, viz. that the sand was not simply iron, but that it was strongly united 

 with a fixed and permanent earth, which could not be separated from it without 

 some powerful means; but he could not think this a sufficient objection to the 

 prosecution of an experiment, which, if it succeeded, might be attended with 

 very happy consequences. Proceeding therefore on this supposition, he mixed 

 up about 8 or 9 oz. of the sand, with a proportional quantity of a strong cor- 

 rosive flux, which he put together into a crucible, and committed it to a very 

 strong fire in an excellent wind-furnace, where he kept it for between 2 and 3 

 hours, hoping by this means to have answered the intended purpose ; but he 

 confesses he was not a little surprised that, after the crucible was taken from the 

 fire, he could not find a single grain of metal in the remaining contents. 



This disappointment greatly puzzled him, till having thoroughly examined into 

 the unexpected event, without being able to discover any reason sufficient to in- 

 cline him to recede from his former opinion, as to the component parts of the 

 sand, he concluded that the flux might possibly be a very improper one; for 

 though it might have effected the intended separation, yet it might at the same 

 time be sufficiently powerful to divide the particles of the metal, when separated, 

 so very minutely, as to be capable of subliming and carrying them off imper- 

 ceptibly ; and finding the contents greatly diminished, so that the quantity re- 

 maining bore but a small proportion to that which was first put into the crucible, 

 he concluded that this must really have been the case, and that some very dif- 

 ferent method must be pursued in order to produce the desired effects. He im- 

 mediately determined to make a 2d trial, in which he proceeded in the following 

 manner. He took the same quantity of sand made use of in the former expe- 



• Vol. iii, p. 495 of these Abridgments. 



