16 UNIV. OF N. IT. AGR. EXPRRiMRNT s'lWTioN [Bulletin 238 



ilarn c(jui]>incnts retained were milking machines, ni(;tor.s, cream separa- 

 tors, water ])uni])s. hay hoists, concrete and fertilizer mixers, flood lights 

 and dairy cooling rooms. 



Detailed cost records for electric dairy cold storage were kei)t on three 

 retail dairy farms. The initial investments for mechanical refrigeration 

 were from $(i3r) to $7()() for an annual load of 9 to l:i hours with 300 

 quarts of hottled milk daily. The annual current consum])tion varied from 

 773 to 1,47!> kilowatt hours a year, and the cost of the current ranged from 

 $37.31 to $75. (U). Power rates varied from a little over 3c to 7c a kilowatt 

 hour. Mgures from the same farms on the total cost of cold storage with 

 natural ice indicate an average of twice the cost of the electrical method. 

 The saving is principally one of lahor ; in fact, the expenses for operating 

 refrigerators were in general less for ice. The initial investments for ice 

 houses were ahout $3()0 less than for electrical equipment. Further details 

 are given in Station I'.udetin V33. ( MisccUancous Inaune.) 



DETERMINING THE AMOUNTS OF SPRAY RESIDUES 



Determinations f)f the amounts of arsenic and lead residues on apples 

 have heen made hy S. R. Shinier. None of the apples taken from the in27 

 crop carried, lead or arsenic in amounts approaching the limits of the 

 British tolerance. It was desired to determine the small amounts of these 

 elements ]iresent with considerahle accuracv, so that such relations might 

 he studied as that hetween the placing of the apple on the tree and the spray 

 residue carried. 



The procedure followed allowed the accurate placing of the apples in the 

 following groups: fl) those carrying not more than one-fourth of the 

 tolerance limit: {'I) more than one-fourth and less than one-half of the 

 tolerance limit: (3) more than one-half and less than three-fourths; (4) 

 more than three- fourths and less than the limit, and (5) more than the 

 tolerance limit. 



"When the tolerance limits are reached, the amounts of the elements can 

 be determined with considerable accuracy. (Purnell Fund.) 



CALCIUM ARSENATE TESTS 



Calcium arsenate when combined with lime sulphur results in less russet- 

 ing than arsenate of lead with the same fungicide according to a six years* 

 experiment by O. Butler and W. L. Doran. Only the faintest russet on 

 the fruit and no foliage injury followed the use of lime sulphur solution 

 1-50 plus 1^> pounds of calcium arsenate to 50 gallons for the prepink and 

 calyx sprays. The maximum injury produced during any year was a 

 smooth, net-like russet, which occurred in 1923. Within the last three years 

 no russeting has occurred at all. During the same years fruit sprayed with 

 lime sulphur and arsenate of lead showed some russeting. 



In laboratory tests acid arsenate of lead in itself show^ed a power to kill 

 the spores of the causal organism. Under field conditions, however, no con- 

 trol was obtained. Further details are published in Technical Bulletin 36, 

 "Spray Solutions and the Control of Apple Scab." (Hatch Fund.) 



