1852.] 119 



July 21 til , 

 Vice-President Bridges in the Chair. 



The Committee to which was referred Dr. Wetherill's paper on the 

 Phocnixville Moljbdate of Lead, reported in favor of publication in the 

 Proceedings. 



Further Examiiiatioii, oj the P hccnixville Molybdale of head. 



By Charles M. Wetherill, Ph. D. 



In the Proceedings for the 30th March of this year, is a description of a red 

 variety of Molybdate of Lead, examined qualitatively by me, and in which it is 

 stated that I could not detect chromium either by the moist way, or before the 

 blow pipe. In the July number of Silliman's Journal, page 105, among the min- 

 eralogical notices by Mr. W. T. Blake, he observes that the specimens from the 

 Wheatley mine, which he mistook for chromate of lead, have been found to be the 

 molybdate containing chromic acid. I find also in Dana's Mineralogy, under the 

 head of this mineral, the observation that " a red variety contains a few per cent, 

 of chromic acid." In my former analysis I looked particularly for this acid 

 without finding it. Supposing that Mr. Blake had been more fortunate than my- 

 self, I repeated the examination on larger quantities of mineral, and with great 

 care, but have no reason to change what was before written. About one deci- 

 gramme of the pulverized molybdate was dissolved in boiling concentrated hydro- 

 chloric acid. No chlorine could be detected, as would have been the case were 

 chromic acid present. After boiling for some time to reduce the hypothetical 

 acid to sesquioxide of chromium, enough water was added to dissolve the formed 

 chloride of lead, and then sulphuric acid in excess. The solution was yellow, and 

 when drops of the liquid had reached the hot sides of the capsule the blue molybde- 

 num compound was formed, which gave with the yellow solution a green tinge to 

 those parts. The lead being thus separated in combination with sulphuric acid, 

 to the filtrate was added hydrosulphuret of ammonium, which kept in solution 

 the sulphnret of molybdenum thus formed, and precipitated sulphuret of iron, which 

 should contain sesquioxide of chromium, if chromic acid were in the mineral. 

 This sulphuret of iron was removed from the solution, oxidized by nitric acid, 

 precipitated hot by ammonia, then washed, and the ashes of the filter fused with 

 nitre and carbonate of soda. The result was the slightest shade greenish, as if 

 from the presence of minute traces of manganese, but not in the least yellow, nor 

 did it give a yellow solution with water, nor did the solution, neutralized exactly 

 by ammonia and nitric acid, give, as would be the case with chromic acid, the 

 purple red precipitate of the chromate of silver on addition of the nitrate. The 

 reactions of chromium are so decided that the presence of this metal could hardly 

 escape the notice of one looking for it. I have not yet been able to obtain a suf- 

 ficient quantity of the mineral for a quantitative examination. This compound 

 may possibly be an acid molybdate, analogous to many chromates which when 

 neutral are yellow, and red when acid. 



The Committee on the following paper by Dr. Wetherill, reported in 

 favor of publication in the Proceedings. 



Chemical Examination of the Food of the Quee7i Bee. 



By Charles M. Wetherill, Ph. D. 



A specimen was given to me by Dr. Leidy, from Mr. Langstroth, of the food 

 of the ^|Ueen bee. It was an oblong mass, consisting of two differently colored 

 layers, the inner one horn-like and transparent, the outer whitish and more 

 opaque. Under the microscope, with high powers, it appears amorphous. It was 



