Deoxidation of Me lab, particularly Silver and Copper, 377 



an hour or more, according to the quantity of silver, and the ra- 

 pidity with which it is cooled. 



If,' instead of coolino gradually, it be made to assume the solid 

 state' suddenly by pouring it into water, still the same phienomena 

 occur ; an ebullition takes place, and oxygen gas is evolved ; but 

 as the silver is so much divided, and passes so suddenly from the 

 fluid to a solid state, the protuberances are proportionably mi- 

 nute, and are spread more equally over the whole surface, as 

 will be seen in specimen No. 2, u • . u -i 



No. 3 shows tiie arrangement of crystallization, which the sil- 

 ver assumes when the gas is separated from it, during the time 

 of its becoming solid. , 



I have before observed, that substances having a powerful 

 affinity for oxygen, will take it from the silver, even while in a 

 fluid state. Thus, if charcoal be spread, for a few moments only, 

 on the surface of silver that has absorbed oxygen, the whole ot 

 the oxygen will immediately be taken from it ; no ebullition or 

 escaoe of gas occurs, whether it: be cooled gradually, as in spe- 

 cimen No. 4, or when poured into water, as in No. 5. By com- 

 paring these two specimens with Nos. 1 and 2, a very great dif- 

 ference will be observed, which is occasioned wholly by the es- 

 cape of gas from the latter, while no such circumstance attended 

 the former. 



The bottle of gas which you will receive herewith, was collect- 

 ed in the following manner. Some silver, after cupellation, till in 

 a state of perfect purity, was poured, by a few pounds at a time, 

 into a vessel containing about 30 gallons of water; and an inverted 

 bottle previously filled with the water, and with a funnel in its 

 mouth, i)eing instantly placed over the silver, as it was each time 

 poured into the water,' the gas, as it was given out and arose from 

 the silver, was thus collected in the bottle until it was filled. 



Care is necessary, that the neck of the bottle be kept below 

 the surface of the water to prevent the access of atmospheric air, 

 and 1 am not very certain that there is not a little admixture*. 

 In addition to 'the above, I have inclosed two samples of cop- 

 per, in two different states, both, however, equally pure, except 

 that the one is believed to be combined with oxygen, and the 



other not. r .i f i c * 



No. 1, is a sample taken from a furnace-full ot about b cwt., 

 when in a melted state, and which had been exposed uncovered 

 to a current of atmospheric air for about two hours before and 

 during the time it was melting. This when poured into water 

 exploded most violently, as will be seen by the small, which was 

 attempted to be granulated. 



• I found this gas to contain 86 or 87 per cent, of oxygen. J. D. 



