70 TRANSACTIONS OF THE 
salt, bicarbonate of soda, potassium nitrate, or the fumes 
of sulfur. In Mexico, the materials are placed in bags, 
pounded and squeezed, and then hung in the sun to dry. 
When meat is dried, it is first rubbed with some material 
which will act as a repellent to flies and insects. With 
the exception of China and Germany, there has been lit- 
tle progress made in foreign countries in methods of dry- 
ing. And even in those two countries the object was not 
to produce a vegetable or fruit for table use in the “near 
fresh” state, but to make a food that could be ground up 
and used as a flour substitute, soup stock, or material 
to be fermented as a source of alcohol. 
In this country, perhaps the first improvements made 
in the methods of dehydration were about 1867 when 
Mr. D. Lippy of Ohio invented a small evaporator which 
was later improved by Topping. From then on for the 
next ten years, many evaporators were invented, mostly 
of the kiln, stack and tunnel types in which the princi- 
ple involved was that of drying by convected heat. 
Other types of driers developed at this time in western 
New York were the steam-tray driers, and air-blast driers. 
Since then there have been improvements and enlarge- 
ments of these types of machines with the addition of 
such labor saving devices as power corers, peelers, slic- 
ers and bleachers. 
Beginning about 1914, there were many evaporating 
and dehydrating machines invented. These are all of 
a more or less complicated construction and operation. 
I will briefly describe six of the more recently invented 
machines together with the principle of their construc- 
tion and the theories upon which their operations are 
based. 
No. 1, patented in 1916. The object of this machine 
is to eliminate as far as possible the handling of the pro- 
duct. This is accomplished by automatically feeding the 
prepared material onto horizontally rotating discs across 
which are passed currents of air of predetermined tem- 
perature and humidity. When the material is dry, a 
scraper is lowered onto the disk and the material moves 
off diagonally into a receiver. 
No. 2, patented in 1917. The theory involved is 
that artificial drying should resemble natural drying in 
