246 PROCEEDINGS OF THE AMERICAN ACADEMY 



The reactions of a solution of this salt iu cold water are as follows. 

 No preci^iitate with salts of copper, zinc, manganese, and cadmium. 

 Argentic nitrate gives a flocky yellow precipitate, with a tinge of buff. 

 Mercurous nitrate gives a bright yellow i^recipitate. Thallous nitrate 

 gives a very pale yellow flocky precipitate, which does not become 

 crystalline on standing. Baric chloride gives no precipitate at first, 

 but after a short time very beautiful sharp octahedral crystals : after 

 lono-er standing small pale yellow very distinct prismatic crystals also 

 appear in the solution. Strontic chloride gives, after some days, 

 very well defined pale yellow prismatic crystals. The solution of the 

 vanadio-molybdate gives a rather dull yellow flocky precipitate with 

 hydro-chloride of brucin, and a bright yellow one with hydro-chloride 

 of strychnin. No precipitate is formed at first with potassic bromide, 

 but after some days beautiful very well defined granular crystals are 

 deposited in quantity. 



The solution of the salt has a strongly acid reaction. The mer- 

 curous salt is decomposed by dilute chlorhydric acid, with formation of 

 mercurous chloride and a yellow acid solution, doubtless of the acid 

 of this series. The acid was decomposed by spontaneous evaporation, 

 and did not yield crystals. 



It appears unnecessary to give a structural formula for the salt de- 

 scribed, since we may regard V^O^ as simply replacing PJJ^, and 

 with the same function as this last, so that the structural formulas 

 already given for the phospho-tungstates will apply to the present case 

 also. 



Uight Atom Series. — When acid ammouic molybdate is dissolved, 

 and vanadic j^entoxide is added in small quantities at a time, the boil- 

 in o- solution quickly becomes yellow, and then orange. If the vanadic 

 oxide is not perfectly free from dioxide, VO^, a little bromine water 

 should be employed to complete the oxidation. If a solution of baric 

 chloride be mixed with the rather dilute and warm solution, no pre- 

 cipitate is formed at first, but after a few seconds an abundance of 

 beautiful yellow well-defined crystals appears. These crystals are 

 very sharp octahedra, and strongly resemble those of one of the am- 

 monium salts of the six-molecule series. After a time granular yellow 

 crystals make their appearance also in large quantity. The habitus of 

 these crystals is so different from that of the first named that the two 

 can readily be separated when mixed. A very approximate separa- 

 tion can also be effected by pouring off the liquid the moment that the 

 granular crystals begin to appear. The yellow octahedral crystals are 

 soluble in hot water, containing a little chlorhydric acid, and may be 



