10 BULLETIN 494, U. S. DEPARTMENT OF AGRICULTURE. 



are very desirable during excessively hot weather. In view of the 

 fact that the only attention needed other than that given the ordi- 

 nary electric l'an is to keep the upper pan filled with water, the 

 operation of this humidifier is simple and practicable. 



RESULTS. 



The use of the humidifier described in this bulletin in lemon curing 

 looms for two seasons has demonstrated the possibility of maintain- 

 ing a uniform condition of relative humidity in such rooms. The 

 action of the humidifier is entirely safe, and there has been no injury 

 t<i the fruit in the curing rooms in which it has been used. 



The maintenance of a uniform condition of humidity in the 

 curing rooms has resulted in an improved curing of the fruits, as 

 shown by the better color and texture of the rind, the green color and 

 firm condition of the calyx, or " button,"" and the juiciness of the 

 lemons, as compared with lemons cured in the ordinary wa}^ in the 

 same building and at the same time. The best condition of humidity 

 for the curing of lemons, as shown by these experiments, lies be- 

 tween 80 and 90 per cent. While the necessity for the use of the 

 humidifier in curing rooms varies in accordance with "the char- 

 acteristic atmospheric conditions of different lemon-growing regions, 

 it can be said safely that in order to maintain uniform conditions of 

 humidity the use of humidifiers is advisable at some seasons of the 

 year in all the lemon districts of southern California. The im- 

 proved appearance and quality of one carload of the fruits held 

 under uniform conditions of humidity through the use of the humid- 

 ifier are likely to more than pay for the humidifier and its cost of 

 operation for the entire year. 



SUMMARY. 



A humidifier for use in maintaining conditions of uniform 

 humidity in lemon curing rooms was invented by the writer in 1914. 



This humidifier was the outcome of a series of experiments for 

 the purpose of controlling the conditions of humidity in lemon 

 curing rooms. 



It has been satisfactorily and successfully used for two seasons 

 lor the purpose for which it was built, and also for improving the 

 air conditions in living rooms in private houses and elsewhere in 

 California. 



The arrangement and structure of the humidifier are described 

 Mini illustrated in this paper. It need not cost, aside from the elec- 

 tric fan. more than $25. 



The lies! condition of relative humidity for curing lemons, as de- 

 termined by these experiments, lies between 80 and 90 per cent. 



