338 a M Munroe on the use of Porous Cones in FUtration. 



No formula has yet been found whicli agrees with either of 

 the percentages obtained. As the atomic weight of antiinmiv 

 is differently stated from 120 to 122, this is easily explaiur^-, ' 



It is unfortunate that the atomic weight of antimonv i 

 so uncertain, but it is hoped that these results, agreeii^. 

 closely among themselves, will be accepted as proving the \. 

 of the process. 



Arseiious Oxide. — This was the next substance analyzed. Th.' 

 sulphide was precipitated in the usual manner, but it was no- 

 ticed that by having the solution decidedly acid aud passing 

 through it a very rapid stream of sulpthydric acid, that the sid- 

 phide was obtained in a more granular condition. 



The precipitate can be dried with impunity at 120". 

 140° the lemon-yellow sulphide commences to change t< 

 and at 180° is completely converted into the liver-red vaii' 



AVith ordinary commercial arsenous oxide, the folio. 

 results were obtained. 



(1) 1-7940 grras. gave 2-2260 grms. As2S3=:75-64 75-76 An 



Mr. Lincoln obtained as the result of t 



gi-ms. gave 1-1087 grms. 1 



These results show that this process renders the estims 

 of antimony and arsenic one of the simplest and most accr 

 operations in qunntitative analysis. 



The cones can be used repeatedly and can replace ]; 

 niters in every case. They will undoubtedly be found to 

 great value in commercial work, for drying crystals and i 

 ing corrosive liquids. xVs they will stand sudden chauL 

 temperature without breaking, thev can be substituted : 

 vantage in many cases for crucibles. 



In closing, I desire to return my sincere tlianks 1» my 

 teacher, Dr. Gibbs, who has furnished me with the inateri: 

 these investigations, and has aided me bv his counse.- 

 advice. 



