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XXXIII. The Apophorometer *. By J. Joly, F.R.S.f 



WHEN recently looking over some o£ my records of 

 experimental work dating back to 1885-86^ I came 

 across a suggestion of an apparatus which, as I now believe, 

 deserves to be disinterred and suitably named. The name 

 at the head of this paper means a measurer of sublimates. 

 The instrument is, in fact, one for enabling sublimates 

 obtained from substances at high temperatures to be collected 

 in their entirety and weighed on the chemical balance for 

 purposes of chemical analysis, identification, or research. 



The apophorometer is a very simple instrument. A ribbon 

 of thin platinum, about 6 cm. in length and 4 or 5 mm. in 

 width, is stretched between two forceps which are provided 

 with binding-screws so that a current can be sent through 

 the ribbon, raising its temperature to any desired degree up 

 to the melting-point of platinum. One of the forceps is 



o ussa 



movable parallel to itself, and is so acted on by a light spring 

 that the ribbon is kept stretched. The substance to be 

 volatilized is placed in the form of powder upon the ribbon 

 or hob. Beneath the ribbon a watch-glass is held in position 

 by a support which can be raised or lowered or rotated to 

 one side. When this watch-glass is in contact with the 

 ribbon a second watch-glass is placed on the lower one. 

 The ribbon is, thus, enclosed between the glasses for nearly 

 its entire length. Over all a receiver fits enabling an 



* 'cnrcxfiopd (dnocpepa) : a sublimate. I owe the suggestion of this 

 name to Professor Henry H. Dixon, F.R.S. 

 t Communicated by the Author. 



