358 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



information on the value and suitability of such products for food, 

 work has been continued in the development and improvement of 

 a food-dehydration industry. 



During the year experimental work on the dehydration of spinach 

 was carried on. Ten tons of green spinach was dehydrated and 

 distributed as samples and sold. The comments upon the quality 

 of the product have been entirely favorable. While it is too early 

 to report upon the keeping quality of the dehydrated product, it 

 had a better color than that usually found upon the market. A care- 

 ful study of the cost of material and of manufacture indicates that an 

 industry in dehydrated spinach could be carried on satisfactorily in 

 some parts of California where the dehydrator may be used for fruit 

 when not drying spinach. 



Experimental work was done in dehydrating cull oranges. About 

 2,700 pounds of dehydrated oranges was obtained from 10 tons of 

 fresh material. This fruit was cull material and showed approxi- 

 mately 50 per cent waste. Some work was done on both cauliflower 

 and onions, the results bringing out special problems which need 

 further investigation before methods can be recommended for the 

 utilization of the surplus crops of these vegetables. Attention was 

 also given to methods for dehydrating cherries and rhubarb. A 

 bulletin on dehydration, giving the data obtained from the experi- 

 mental work, is in course of preparation. 



IMPROVING PRODUCTION OF ROSIN AND TURPENTINE. 



Naval stores of which turpentine and rosin are the most impor- 

 tant, are faiTn and forest products that enter commerce in the form 

 of paints, varnishes, soaps, paper and textile sizes, polishes, and in- 

 numerable other manufactured articles. Twenty-five million dollars' 

 worth of turpentine and rosin are thus used in this country each 

 year and quantities of approximately the same value are exported 

 annually. 



The investigations of methods of producing, weighing, handling, 

 and grading and of the uses of rosin and turpentine have been con- 

 tinued. 



The work is along two general lines: (1) Research on the prop- 

 erties of turpentine and rosin to determine the characteristics that 

 control their adaptability to various uses, on improvements in 

 methods of using turpentine and rosin, and on the differences be- 

 tween similar products made from the oleoresin or gum of the living 

 tree and those made by steam or destructive distillation of pine 

 wood; (2) laboratory and field studies on improvements on the 

 methods of producing, packing, handling, shipping, and grading 

 these commodities and other less important naval stores derived 

 from the pine tree, as well as a study of the adulteration and 

 methods of analysis, detecting the extent of adulteration, and the 

 formulation of specifications for naval stores. Statistics are col- 

 lected annually on the consumption of turpentine and rosin in the 

 various industries and on the stocks held by consumers and by 

 dealers and jobbers at the principal distributing points of the 

 country. These statistics are published each year jointly with the 

 statistics of the Bureau of the Census on production and stocks held 

 by producers, in the preparation of which the Bureau of Chemistry 

 assists. 



