FIELD KXPERIMENTS. 



47 



arsenic found. Theoretically the amount of arsenate of lead 

 should be exactly the same when calculated from the arsenic 

 as when calculated from the lead. It will be noted, however, 

 that the arsenic found was considerable in excess of the lead 

 needed to make arsenate of lead. In other words the arse- 

 nate of lead calculated from the arsenic found is a half more 

 than that calculated from the lead found. No explanation of 

 this discrepency is offered. The chemical work was carefully 

 checked. It is a matter of no practical, importance but it has 

 occupied the attention of quite a bit of the time of the chemists. 

 In order to make sure that all of the arsenic was removed by 

 this washing in the laboratory samples of the washed peelings 

 from two different lots were examined and the results show 

 that they were entirely free from arsenic and, therefore, all of 

 the arsenate of lead was removed by washing. The results 

 of the analyses are given in the following table : 



Table showing results of analyses of apples sprayed with 

 arsenate of lead. 



Sta. 

 No. 



Variety of Apple. 



Number apples 

 tested. 



Amount 

 arsenic 

 oxide 

 found. 



Amount 

 metallic 



lead 

 found. 



Arsenate of lead 

 per apple calcu- 

 lated from 

 arsenic lead. 



116iJ 

 11615 

 11646 

 1163? 

 11639 

 11640 

 11641 

 11642 

 11643 

 11637 



lalcUvin. 



Ben Davis. 



Russets . 



Numbei 



Weight 

 g-j-ams. 



Mgr. 



Mgr. 



Mgr. 



43 



4600 



4.305 



8.673 



.454 



45 



5600 



3.690 



7.S53 



.372 



49 



7100 



3.690 



7. £53 



.342 



47 



5900 



2.153 



3.722 



.208 



50 



6&50 



2.460 



5.600 



.233 



45 



6700 



1.53£ 



3. 381 



.140 



47 



5450 



2.460 



5.258 



.238 



47 



7000 



4.610 



8.330 



.445 



47 



5650 



4.305 



8.673 



.416 



45 



4100 



2.460 



4.917 



.248 



Mgr. 



.292 

 .252 

 .232 

 .114 

 .162 

 .108 

 .162 

 .255 

 .267 

 .15b 



Arsenic in the form of arsenious oxide is frequently admin- 

 istered as a tonic. The maximum dose is five miilligrams and 

 is continued at the rate of not to exceed ten milligrams per 

 day. The washings from about ten pounds of apples carry at 



