NOTES AND ABSTRACTS. 



225 



or no soluble arsenite was present. Comparing the analyses, the 

 moisture contents vary considerably in most cases ; a high moisture con- 

 tent is accompanied by a low percentage of arsenic acid. The samples 

 varied from 22*2 per cent, up to 73'3 per cent, moisture; from 18*87 

 to 44*06 per cent, lead oxide ; from 7*80 to 14*70 per cent, arsenic oxide. 

 The average analysis of the fourteen samples gives 45*81 per cent, 

 moisture; 35"46 per cent, lead oxide; 12*17 per cent, arsenic oxide. In 

 England at present Swift's arsenate of lead is most used for spraying; 

 its analysis gave 44'6 per cent, moisture; 37"28 per cent, lead oxide; 

 15'23 per cent, arsenic oxide; 0"35 per cent, water-soluble arsenic. 



A Bill has been prepared for United States Congress providing that 

 arsenate of lead shall be deemed to be adulterated if it contains more 

 than 50 per cent, of water ; total arsenic equivalent to less than 12^ per 

 cent, of arsenic oxide; or soluble arsenic equivalent to more than 

 0*75 per cent, of arsenic oxide. Water-soluble arsenic should be low, 

 as the danger of burning leaves is due to this, while the arsenic oxide, 

 the killing property to caterpillars, should be high. Arsenate of lead is 

 a useful destroyer of slugs and snails on plants that are not used for 

 food.— C. H. H. 



Arsenical Sprays, Guides in the Use of. By C. J. Carmody 

 {Jour. Dep. Agr. Vict., September 1909', pp. 584-589).— (a) No pre- 

 paration should be used as a general spray without first testing it on 

 a tree (or portion of a tree) of the different varieties to be treated, 

 unless the grower has had previous experience with that particular 

 brand. 



(b) Some varieties are more susceptible to arsenical influence than 

 others, * Bismarck ' being the most noticeable in this respect in the 

 author's experience. 



(c) Weak, stunted, water-logged trees are less resistant to burning 

 than young vigorous ones. 



{d) In moist or foggy weather this spray is far more injurioua 

 than when the weather is warm and equable. 



(e) Water used in mixing the sprays should be free from any acids 

 that will act as a solvent on the arsenic. 



(/) Vessels, pumps, nozzles, hose, etc., should be thoroughly clean, 

 and free from Bordeaux mixture or any active agent that would cause 

 mechanical or chemical changes to take place. 



{g) The safest sprays are those having the least amount of soluble 

 arsenic in their composition. 



(h) The spray should be continuously and thoroughly agitated from 

 the bottom of the pump up to the surface. 



(i) Repeated spraying with arsenic, when not wholly insoluble, often 

 sets up a kind of chronic derangement of the cellular tissues of the 

 leaves not at first noticeable, but which causes the leaves to pre- 

 maturely turn yellow and fall off. 



{j) Extreme care should be exercised with the handling, storing, 

 and application of these sprays. They should not be used at the 



VOL. XXXVI. Q 



