234 [December, 



I have noticed tbis quarts scattered over the ground m various parts of 

 Berks county, some specimens bearing very strong gold characteristics; they are 

 partially water worn, but the angles are moderately sharp on breaking them 

 open the enclosed masses of dark oxide of iron a?e apparent. 



At the angle formed by the intersection of 8th and 9th streets, Reading, there 

 3 a heap of stones gathered from the adjoining fields, containing about two per 

 cent, of pieces of this quartz rock ; I brought home specimens with me for ex- 

 amination. These specimens, together with those obtained from Mr. Deininger's 

 field by myself, were pulverized and washed, but without, in any instance, detect- 

 ing gold. They were then smelted with litharge and charcoal, and the button 

 of lead cupelled. Of course, the litharge was examined for gold. The 30 gramme 

 button of lead from about 100 of litharge gave a silver button of 0.00575 grms., 

 and which contained no gold. 



A. 8th street quartz 65 grammes -f- 13-0 litharge -J- 10 black flux gave a lead 

 button of 14 grms., and silver 0.0075, which contained gold beyond a doubt, as 

 judged from its lustre and resistance to nitric acid, 



B. Another portion of quartz from the same locality 20t) grms 4- 400 lithrage 

 -f- 0.5 charcoal dust, gave lead IT grms. ; silver 0.008 7 5 containing gold,, though 

 not as distinctly as the last. 



C> Quartz from Mr. Deininger's fields 185 grms. + 370 litharge -j- 0.5 charcoal 

 gave 20 grms, of lead containing 0.00825 silver, in which no gold could be detected. 



On the Incineration of Filters in Analysis. In order to burn off the filters from 

 eertain precipitates i.i quantitative analysis, considerable pa-tienee is required 

 and loss of time involved,, owing to the presence of salts in the pores of 

 the filter. Fresenius, in his last edition of Quantitative Analysis, counsels patience 

 in such cases, and to facilitate the combustion by pressing tne filter against 

 the hot crucible by a platinum wire. I have found it advantageous, in such cases, 

 to use oxygen gas, as is done in some of the methods for preparing ashes of plants 

 for analysis. The results are good, and none of the contents of the crucible are 

 lost. The phosphate of magnesia-ammonia filter is thus burned off in quite a 

 short time, and without any loss of phosphoric acid. After the filter is car- 

 bonized, the lid is partially removed from the upright crucible, and a tube (plati- 

 num I use, but glass will do nearly as well,) with an orifice of one mm. in 

 diameter, delivers oxygen gas from a small vulcanized caoutchouc bag, so slowly 

 that it miugles with the air in the crucible and effects the combination quietly, 

 A crucible appears to be in the worst position possible for oxidation in the 

 manner in which it is situated in the flame, for the rising air currents are un- 

 favorable for combustion in the bottom of the crucible, and the air which does 

 enter is diluted with the products of combustion. Though this may be par- 

 tially improved by an inclined position of the crucible and lid, it is not obviated , 

 and oxygen gas seems to afford a remedy with less risk than nitrate of ammonia.* 

 1 have not yet found any objection to its use from practice, and pure oxygen is 

 so readily obtained from the commercial chlorate of potassa by using the wash 

 bottles described in my article on " organic analysis by gas," and keeps so well 

 in vulcanized caoutchouc bags that I would recommend it to a trial. 



Apparatus for the Analysis of Carbonates. Both in Fresenius' late edition 

 of Analysis and in Rose's greater work are described apparatus for the de- 

 termination of carbonic acid by Fresenius' and Wills' process, using fine 

 balances. About a year and a half ago I described, in the Journal of the 

 Franklin Institute, a very convenient apparatus for this purpose, which 

 as it appears not to have come to the notice of chemists generally, and 

 as those of my chemical friends who have tried it have approved of it, I 

 will here shortly describe. 



* Schultze (Fresenius' Anal.) proposes to burn filters and plant ashes by 

 creating an air current over the crucible by means of a broken retort neck, 

 j- Franklin Inst. Jour., Aug., 1854, page 107. 



