336 C. E. Munroe on the use of Porous Cones in Filtra 



3. On the X 



i Filtratio 



Tlie sulphides of arsenic and antimony being quite easily 

 obtained have long been regarded as furnishing the readiest and 

 best means for the estimation of these two elements. A serious 

 objection has however arisen in the fact, that they must be de- 

 termined upon weiglied 

 filters, and that paper fil- 

 ters cannot be dried above 

 100° without danger of 

 loss. Hence a filter which 

 could be weighed easily 

 and withstand a high 

 temperature became a de- 

 sideratum. 



Taylor* accomplislied 

 this with sand filters, ana 

 obtained some excellent 

 results. This method, 









and careful 

 ipulation, reasons whieli 

 will probably prevent its 

 1 being generally used. 

 Under these circum- 

 ■ances the idea of using 

 cone made of very por- 

 ous earthenware, and as a substitute for the paper filter, pre- 

 sented itself to me, and has been carried out in the following 

 manner. 



r grms. Mg,P207=36-l 



lour. This method 

 With this i'ldditioi 



