SO Journal of the Mitchell Society. [March 



Our work seems to indicate that in the formation of the 

 sulphate a mixture is formed. The portion of the sulphate 

 next to the crucible may have been decomposed while the 

 inner portion would still be acid sulphate. Since the atomic 

 weight determinations carried out by other investigators were 

 not made at a definite temperature, then from our investiga- 

 tions the values might have a wide range. Of course, if a 

 series were carried out under exactly the same conditions, con- 

 cordant results would be obtained. But still there would 

 remain the question whether all the body was normal sulphate 

 or acid or part acid and part basic. 



The determination of the equivalent from the acetonyl-acet- 

 onate next claimed our attention. The crystals of acetonyl- 

 acetonate were made, but they showed two forms of crystals 

 so that they were not used. The 'obvious disadvantage of 

 using such a compound has already been mentioned. 



After considering the various methods upon which the 

 equivalent of thorium is dependent we decided to try a new 

 method. Of the compounds of thorium considered the tetra- 

 chloride seemed to offer the greatest advantages. By its use 

 the ratio could be determined between the oxide and the 

 chloride, and the values of only three elements would be 

 involved. 



The thorium oxide was ground up in an agate mortar with 

 carbon (about one-tenth the weight of the oxide) and the mixture 

 placed in a carbon boat. The boat was placed in a hard glass 

 tube passing through a combustion furnace and while heated to 

 a good red heat, dry chlorine passed through the tube. Beau- 

 tiful crystals of the chloride formed on the walls of the tube 

 just beyond and above the boat. Still farther, lighter and 

 feathery crystals formed in the tube, and a white vapor, Ber- 

 zelius's "Weisserdampf", was driven off and caught in alco- 

 hol. 



The carbon used was obtained by heating crystallized rock 

 candy. The boats were previously heated in a stream of dry 

 chlorine for several hours. The chlorine used was taken from 



