TO Sept.. 1910.] 



Spri)ii^ Frosts. 



60 E 



about $25 per acre. The cost of operating is about $5 ])er acre per night, iujlud- 

 ing labour and oil. 



Another type uf lire pot burning coal is the ' IdeaU"' in which 15 lb.s. 

 coal will burn for 3I hours, and 25 lbs. 5^ hours. 



According to the prospectus the Olson coal orchard heater is a sheet 

 iron pot measuring 18 inches across the top, 9 inches on the bottom, and 

 12 inches in depth. ... It burns from 15 to 50 lbs. coal per night, 

 depending entirely on service required. Two men can charge 50 pots in 

 40 minutes, and one man can light them in three minutes. In a reasonably 

 close orchard 40 to the acre will do the work and save the crop with a 

 temperature of 10 degrees below freezing. 



These few extracts, as well as the photograph reproduced from the 

 " Olson '" prospectus, in which the pots' are much closer to one another 

 than is necessary, will give some idea of the practical results alreadv 

 obtained by this novel method of frost-fighting, in which the heat directly 

 radiating from the fire pots makes goofl the natural loss by radiation into- 

 space. 



COLORADO FIRE POTS OR ORCHARLi llIiAlERS. 



In the 1 910 edition of Calif ornio. Fruits and Hoic to Groiv Theniy 

 Profes.sor Wickson refers to orchard heaters, quoting Mr. E. W. Holmes. 



Satisfactory results have been gained by the use of soft coal, burned in wire 

 baskets suspended under or beneath the trees. When 20 to 40 of these to the acre 

 were used, we occasionally raised the temperature from 3 to 5 degrees. More 

 has been claimed ; but this is all that I am sure has been achieved. However, in a. 

 section where the temperature would not go below iz, degrees or 26 degrees for a 

 few hours, this method was ample. The outfit costs about 10 cents a basket, or 

 4 dollars per acre if 40 baskets are used, and the coal about 2^ dollars per acre per 

 night. 



Smudge -fires, or artificial clouds, as they are picturesquely termed iir 

 French, are not. like the last-mentioned method, in any way a novelty ;. 

 thev have been known and used for manv centuries. Plinv recommends; 



