On the Chemical Properties aitriluted to Ligfit. 4©e 



On examining, with a good microfcope, the particles of revived gold which remained 

 attached to the furface of the charcoal, after it had been dried, I found them to confift of 

 an infinite number of fmall fcales, feparated from each other ; not very highly poliflied, 

 but pofleffing the true metallic fplendour, and a very deep and rich gold colour. 



The gold which attached itfelf to the infide of the glafs tube, was in the form of a ring, 

 about Tg of an inch wide, (badly defined however below,) and adhered to the glafs with fo 

 much obftinacy, as not to be removed by rinfing out the tube a great number of times with 

 water ; it had, as has already been obferved, a very high polifh, when feen by reflefted 

 ligfit. 



Thofe who enter into the fpirit of thefe inveftigations, will eafily imagine how impatient 

 I muft have been, after feeing the refults of thefe experiments, to find out whether gold 

 could be revived from this aqueous folution of its oxide by means of charcoal, nvithout the 

 ajfijlance of lights and merely by fuch a degree of equaf heat as could be given to it in the 

 dark. To determine that important queftion, the following experiment was made. 



Experiment No. lo. — A cylindrical glafs tube, -^% of an inch in diameter, and lo inches 

 long, clofed hermetically at its lower end, and containing a quantity of a diluted aqueous 

 folution of the oxide of gold, mixed with charcoal in broken pieces, about the fize of large 

 peas, was put into a fit cylindrical tin cafe, which was nicely clofed with a fit cover; and 

 the glafs tube, with its contents, fo (hut up in the dark, was expofed two hours. In the 

 temperature of 2 1 o° of Fahrenheit's fcale. 



On taking the glafs tube out of its tin cafe, I found the {olution perfe^ly cokurk/s, and 

 the revived gold adhering to the furface of the charcoal. 



On repeating the experiment, and ufing the folution nearly faturated with the oxide, the 

 refult was precifely the fame ; the folution being found perfeQly colourlefs, and the re- 

 vived gold adhering to the furface of the charcoal. 



I own fairly, that the refults of thefe experiments were quite contrary to my expefla- 

 tlons, and that I am not able to reconcile them with my hypothefis, refpefting the caufe* 

 of the reduftion of the oxide. In the foregoing experiments ; but, whatever may be the fate 

 of this, or of any other hypothefis of mine, I hope and truft that I never (hall be fo weak as 

 to feel pain at the difcovery of truth, however contrary It may be to my expedlatlons ; and 

 ftill lefs, to feel a fecret wi(h to fupprefs experiments, merely becaufe their refults militate 

 againft my fpeculative opinions. 



It Is proper I (hould obferve, that the charcoal ufed in this laft-mentloned experiment 

 had been boiled two hours In diftllled water ; by which means Its pores had been fo com- 

 pletely filled with that fluid, that the pieces of it that were ufed were fpecifically heavici; 

 than water, and funk in it to the bottom of the containing velTel. 



(To be continued.) 



Vol. II.— Dec. J 798. 3G Vl. Expe. 



