Septembeb 3, 1909] 



SCIENCE 



317 



Hum dissolve varying quantities of beryllium car- 

 bonate or hydroxide according to the concentra- 

 tion of the acid solutions used, and, further, that 

 the freezing point of solutions containing this 

 material was raised rather than lowered by in- 

 creasing the quantity of the beryllium hydroxide 

 dissolved, this evidence of constitution is over- 

 thrown. 



Quite different from these weak acids, however, 

 was the case with the comparatively strong tri- 

 chloracetate Be(CCl,COj)32H,0, which does yield 

 a perfectly definite compound if prepared, as salts 

 of beryllium of this kind must always be pre- 

 pared, from solution containing an excess of the 

 acid. This salt was made in several different 

 ways and repeatedly recrystallized, and was shown 

 to have perfect definiteness of composition, losing 

 its two molecules of water of crystallization at 

 100°. We have no hesitancy in saying that none 

 of the above mentioned acids can be prepared as 

 definite compounds from water solution with the 

 exception of the trichloracetate, and it is probable 

 that this will be found to be true of most acids 

 having a dissociation constant lower than that of 

 trichloracetic acid. Attempts were also made to 

 make definite salts of these acids from solution 

 in organic solvents, but without success. 



The Bromates of the Rare Earths — Part II., The 



Bromates of th€ Cerium Group and Yttrium: 



C. James and W. F. Langelieb. 



The pure bromates of lanthanum, cerium, pra- 

 seodymium, neodymium, samarium and yttrium 

 were prepared from the pure sulphates by treating 

 them with barium bromate and their properties 

 studied. 



All of these bromates were found to have the 

 formula R^CBrOjj.lSH.O and when heated to 100° 

 they were all converted into a hydrate containing 

 4HjO with the exception of j-ttrium bromate, 

 whose hydrate at 100° contains 6HjO and cerous 

 bromate. They all lost their water of crystalliza- 

 tion and became anhydrous at 150° and at a 

 higher temperature they were all decomposed 

 with evolution of both light and heat. Indeed, 

 praseodymium bromate loses all of its water of 

 crystallization at 130° and decomposes at 150°, 

 while cerous bromate decomposes at a much lower 

 temperature, approximating 50°. In water solu- 

 tion cerous bromate gradually evolves oxygen, 

 precipitating an insoluble residue and leaving 

 behind in solution probably eerie bromate, which, 

 however, was not isolated on account of the ease 

 of its decomposition, its strong aqueous solution 



being indeed so active an oxidizing agent that it 

 causes explosive combustion of organic material 

 such as filter paper or cotton when poured upon it. 

 The general results may be summarized as fol- 

 lows: 



Melting 100 Parts HjO 



Point Dissolved 



Laj(Br03)..18H,0 37.5 416 



Ce,(BrO.),.18H,0 49 



Pr3(BrO,)..18H,0 56.5 190 



Ndj(Br03),.18HjO 66.7 146 



Sm:(Br03),.18H,0 75 114 



Yts(Br03).. 1811,0 74 168 



Some Physical Properties of Sulphur Trioxide: 

 D. M. LicHTY, University of Michigan. 

 Sulphur trioxide, purified by repeated distilla- 

 tion of the commercial article over pure phos- 

 phorus pentoxide in a vessel' exhausted to 50 mm. 

 or less, melts sharply at 16.8° (Weber 14.8°), 

 boils at a temperature not exceeding 44.8° under 

 760 mm. pressure, and seems to be purer than that 

 prepared by Weber.' If kept from contact with 

 moisture, it retains its sharp melting point and 

 at room temperature is in appearance a very 

 transparent mobile liquid which really consists 

 of a liquid variety, containing, dissolved in it, and 

 presumably in equilibrium with it, a considerable 

 quantity of a solid variety. The depression of the 

 freezing point of phosphorus oxychloride, caused 

 by this mixture, leads to the formula SOj.' The 

 coefficient of expansion is very high, agreeing 

 essentially with that found by Schulz-Sellak* and 

 by Schenck.' If exposed to a relatively small 

 amount of moist air, the liquid solidifies more 

 or less completely at room temperature. The de- 

 pression of the freezing point of phosphorus oxy- 

 chloride, produced by a completely solidified 

 sample, also leads to the formula SO3. The ordi- 

 nary asbestos-like needles seem to be a polymer 

 having the formula SjOc.' 



Ihe Modern Manufacture of White Lead: J. S. 

 Standt. 



The paper gives the description and chemistry 

 of the various processes of white-lead manufacture 

 in use, including the Old Dutch, English, French, 

 Milner's, etc. It enumerates some of the more 

 important English and American patents. 



' J. Am. Chem. Soc, 30, 1836. 



'Pogg. Ann., 159, 313 (1876). 



'Oddo, Gazz. chim. ital., 31, II., 158 (1901). 



'Ben., 3, 215. 



'Ann., 316, 1 (1901). 



' Oddo, loc. cit. 



