326 PERSISTENCE OF ARSENITE. 



Sample C. — Composite sample of the manure from another part of 

 the heap; top, middle, and bottom. 



In Air-Dried Samples. 



A 2A 3A B 2B 3B C 



Per cent. Per cent. Per cent. Per cent. Per cent. Per cent Per cent- 

 Arsenic as 

 Arsenite .081 .011 .001 .024 .016 .002 .001 



In Original Samples as Taken. 

 Arsenic as 

 Arsenite .068 .007 .'3005 .020 .nij .oooS .0004 



Though little danger would result from the use of such manure, a 

 sample such a "A" might cause trouble, and on tliat point it would be 

 well to caution farmers. 



Where the leaves have been sprayed for some time, and where there 

 are signs of soaking through the leaves, such manure should !>e well mixed 

 with the bottom layers. 



In connection with the above, Mr. Crawford carried on plot 

 experiments in the field to determine the effect of baited manure 

 on barley. On 30th November he reported that there was not 

 arsenite of soda enough to have any effect. 



Two samples from a heap of manure accumulated under 

 treatment with house-fly bait, the same as the Elsenburg- sam])les 

 given above were secured from Mr. C. W. T. Duminy's farm, 

 " Thalman," Bellville, C.P., and submitted to the Government 

 Analyst, Dr. C. F. juritz, to determine the amount of arsenic 

 present. 



For Sample i, manure was collected in small forkfuls over 

 the surface of the heap, becatise it seemed likely that the surface 

 layer would be richer in arsenic. This was thoroughly mixed, 

 so as to secure uniformity before taking the sample for analysis. 



For Sample 2, manure was taken from two parts of the lieap 

 where the bait had been persistently used. It was taken in the 

 same manner as if loading a cart or wagon, so as to re])resent a 

 quantity of manure as usually spread on to the land. After 

 thoroughly mixing the manure the sample was taken. 



The following are Dr. Juritz's results and his interpretation 

 of them : — 



The amounts of arsenite, calculated as AS2O3, amount to .014 per cent, 

 in No I, and to .0055 per cent, in No. 2. In other words, a ton {2,000 lbs), 

 of No. I would contain .28 of a pound weight, or about 4^ ozs. of arsenious 

 oxide, and such a ton, if applied to an acre of soil, and mixed with the 

 latter to a depth of six inches, would add arsenious oxide to the soil 

 .000014 per cent, of the latter's weight — a quantit}- far too minute to 

 exert the slightest harmful efifect on vegetation. Similarly, a ton of No. 2 

 would contain .n of a pound weight of arsenious oxide, and, if mixed 

 with an acre of soil to a depth of six inches, would add to such soil 

 .0000055 per cent- of arsenious oxide. 



I assume tliat, roughl}-, an acre of soil six inches deep, weighs i.ooo 

 tons. 



Seeds planted in soil with a liberal dressing of this manure. 

 compared with unbaited manure at the Fxperiment Station, 

 Rosebank, showed no ill eft'ects whatever. 



