584 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
steam-coil, the pressure and heat in which are regulated to suit the 
product in band. Next the steam-coil is placed a deflector to distribute 
the air-blast more uniformly throughout the shaft. This may be adapted 
to hold adeposit of water, which is sometimes desirable for giving a degree 
of humidity to the air-blast at its first entrance to the shaft; or deposits 
of water may be arranged at other points and in other modes to supply 
the humidity, which is an essential element in the process of preserving 
organic products. Behind or beneath the steam-coil is an air-chamber, 
into which air is forced by a suitable apparatus, such as a fan blower. 
The material under treatment, having been first divided so as to expose 
the most extended surface possible to the action of the pneumatic appa- 
ratus, is spread on a screen and may be introduced into the pneumatic 
shaft at the end near the steam-coil. After remaining here exposed to 
the blast for a suitable time, according to its nature, it is passed onward 
by a movement of the carrying apparatus on which it rests, and a fresh 
screen (or screens) is introduced into the place thus vacated. The blast 
in passing through these screens covered with fresh material now carries 
_ with it an increased burden of moisture derived from them as it strikes 
upon the screens that have gone on before. With every forward move- 
ment of the carrying apparatus fresh screens are introduced, and the 
moisture of the blast is increased by them. When the pneumatic shaft 
is filled with the series of loaded screens they begin to be taken out at 
the terminus of the shaft, in a perfect condition of the material, as fast 
as the crude material is introduced at the entrance. The processis now 
in full operation. The blast, which enters the shaft with a slight degree 
of humidity and a temperature of from 175° to 200° Fahr., according 
to the article, gains moisture and loses heat at every loaded screen 
through which it passes, and finally leaves the perfected material at the 
terminus reduced in temperature to say 100°, and yet throughout its 
progress does not cease to act at once as a hydratic mediator in the con- 
version of the starchy ingredients to grape sugar, and also as a mechan- 
ical evaporator and absorbent, with such effect that the amount of free 
moisture left in the material at the terminus is of no practical conse- 
quence, and never produces fermentation or decay. 
The temperature of the air in the lower part of the tower is from 1909 
to 200° Fahr., and as the air rises it gradually cools off, so that in the 
top part of the tower the temperature is from 120° to 130° Fahr. These 
temperatures are maintained in drying fruit, such as apples, peaches, 
tomatoes, &c.; but for other substances the temperature must be varied, 
as experience will dictate. For drying meat, for instance, the tempera- 
ture may be slightly decreased, and it must not rise above 1509 ahr. 
in the bottom part of the tower. 
By introducing the green articles in the bottom part of the tower and 
moying them in the same direction in which the air moves a great ad- 
vantage is gained, since the air on coming in contact with the green 
articles takes up a quantity of moisture, and as the air rises the quan- 
tity of moisture taken up by it constantly increases, while at the same 
time the moisture contained in the articles spread on the successive 
screens constantly decreases. By this process the skin of the articles 
to be dried is prevented from becoming hard, and the articles are 
thorough and uniformly dried. Per contra, if the screens were introduced 
at the top of the tower and moved against the current of the air, the 
articles to be dried would become hard, and the interior of these articles 
would be imperfectly dried. 
It is claimed by the inventor of these improved methods of drying 
fruit that growth and development in the vegetable, as also in the ani- 
