1910.] Protection of Orchards from Spring Frosts. 561 



also used to a limited extent, as well as lignite coal. The 

 wood and coal were used to raise the temperature of the air 

 in the orchards, but the rubbish, straw, &c, were prin- 

 cipally employed to produce a dense smudge or smoke to 

 protect the orchards from the direct rays of the sun in the 

 early morning after there had been some freezing of the 

 blossoms. 



The fires were started with shavings or mill planings, saw- 

 dust, straw, crude oil, light brush, and rubbish or rakings 

 from adjoining woods, one of the best materials being mil] 

 planings placed in medium-sized paper bags and saturated 

 with crude oil or kerosene, these bags being prepared before- 

 hand in considerable numbers. In some cases kerosene was 

 poured direct on to the coarse material, but this plan was 

 more expensive and not so effective. A kerosene torch was 

 found useful for lighting the fires, as it did not blow' out, 

 and with this the fires for an acre could be lighted by one 

 man in from seven to ten minutes, the number of heaps 

 being from 40 to 50 per acre, placed between every second 

 row of trees in each direction in the orchard. If the tem- 

 perature is not very low and only needs to be raised 5 or 

 6 degrees, not more than 25 fires to the acre may be neces- 

 sary, while 50 will be required if the temperature falls to 

 20 0 F. and needs raising by 8 or 9 degrees. In case the tem- 

 perature cannot be kept up to 28 0 F., it is recommended 

 that a certain amount of damp straw or stable manure should 

 be placed on the heaps on the windward side of the orchard 

 before the sun rises, in order to produce a dense smoke and 

 prevent too rapid thawing of any slightly frozen fruit or 

 blossoms. 



The fires should not be so large as to produce an intense 

 heat, and so create a sharp upward draught. Large fires 

 are also liable to scorch the blossoms. When stable manure 

 or rubbish was used, more heaps were placed in position, 

 each averaging about a bushel or a bushel and a half. 



The cost of the material varied greatly, but in general the 

 cost for one night was 8s. to 10s. per acre. When stable 

 manure and rubbish alone was used, the cost was naturally 

 much less. Labour for firing averaged about 45. 



The conclusion arrived at by the United States officer, 



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