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AMERICAN POMOLOGICAL SOCIETY. 
FRUIT EVAPORATION. 
BY DR. J. R. CARDWELL, PORTLAND, OREGON. 
Mr. President, Members of the American Pomological Society, Ladies and 
Gentlemen: 
Your Secretary has asked me to write a paper on fruit evaporation. An 
intelligent member has suggested that it should be a short, meaty paper; the 
first requirement I shall fill. 
The development of the fruit industry in this country, the phenomenal 
yield in the Pacific coast states of all the fruits of the tropic, semi-tropic and 
temperate zones, has taxed to the utmost the inventive genius and capital 
of our most enterprising citizens. Sundry chemical processes, scientific pack- 
ing, refrigeration, rapid transit— these have greatly facilitated the distribution 
of green fruits in their season to distant markets. Various culinary 
devices and new processes, wineries, distilleries, the making of unfermented 
liquors, vinegars, jams and jellies, glace fruits, sun drying and machine 
evaporation— these are all operated on a scale hitherto unknown, with invest- 
ment of immense capital and giving employment to great communities. Sun 
drying in California and other favorable districts in the southern states with 
the improved methods of handling, dipping, sulphuring, etc., is now a business 
of immense magnitude, bringing to the Pacific coast alone more than ten 
million dollars annually; and yet all these industries must be ten times multi- 
plied and extended to utilize the yield from orchards and vineyards now set. 
New conditions and demands of the times will be met, appliances will be im- 
proved and cheapened; transportation facilities will be extended and rates re- 
duced to insure a wider distribution to the world’s markets. 
The fact is apparent that consumption must be increased to meet the out- 
put. The prune trees set on the Pacific coast, will in five years more than 
supply the present world’s demand, and perhaps as much may be said of the 
raisin grape and other fruits. 
Fruit evaporation of today is a comparatively recent industry. About the 
years ’79 or ’80 the first large patent evaporator (the Alden), was introduced in 
California and Oregon. It was a stack machine, requiring a two-story build- 
ing, lacking in capacity and not adapted to the slow drying of the prune. The 
plans or buildings and appurtenances, and methods of working introduced by 
the promoters were expensive and impractical. This was soon discarded. Then 
came the Plummer, the first steam apparatus with boiler, radiating pipes 
under rotating trays with no system to control the entrance of cold air or to 
deflect and regulate the heat, to create the requisite draft and carry off the 
moisture, so this proved to be a veritable sweat box, not a success and was 
also discarded. 
Then came the American Evaporator, a side-draft or tunnel device of simple 
construction and economic working; popular with the farmer and small 
grower. 
Enlargement and modifying of these three devices has been the basis for 
more than a thousand patent evaporators; brain and muscle are still active in 
this line. 
Dr. J. F. Simonds has so* well stated the chemical changes that take place 
in fruit evaporation, that I take the liberty of quoting: 
“I will now describe the process of true evaporation. It has been found 
that by removing a part of the water rapidly, in swift moving currents of air, 
