838 



THE TROPICAL AGRICULTURIST. 



[April 2, 1883. 



climate in Ceylon is especially inimical to such an 

 article as tea, and the sooner prepared tea is ex- 

 ported the better; but this question of the suificient 

 thickness of the sheet lead used is too important 

 not to receive immediate and careful attention. A 

 series of experiments should be instituted to set the 

 question at rest. The saving of 2-7ths of the lead 

 used in packing may be dearly purchased if our 

 teas get the reputation of not keeping well,— or not 

 so well as China teas. 



I had also just received (all the way from Amer- 

 ica) in time to shew Mr. Cameron, a representation 

 and description of "the latest imeoved auto- 

 matic FRUIT evaporator," patented by McFarland 

 & Wilt of Philadelphia. We were all amused to find 

 that— furnace below, arrangement of trays above, 

 chimney &c.— we were looking at a very close like- 

 ness of a tea drier: a gigantic "sirocco," in fact. 

 I wrote of the ten trays (not the tin trays as the 

 printers made it) of our improved Jackson's drier 

 (which is doing excellent work) ; but the fruit evapor- 

 ator, intended to prepare apples, peaches, &c., 

 for export, has, we should say, from the picture, 

 thrice ten trays fitted into it. Our tea driers are 

 intended to expel all moisture : the principle, there- 

 fore, is that of the kiln or oven. But the fruit eva- 

 porator, ahhongh requiring so high a temperature as 

 212 to 240 degrees, requires also that the air in 

 which the fruit is evaporated should be saturated 

 with moisture. It is contemplated that fruit should 

 come out of the evaporation with 12 per cent of 

 water in it. In this state it is said it can be put 

 by in a dark closet and preserved indefinitely; or 

 better still put up in boxes lined with paper and 

 kept in a cool place. It might be worth while im- 

 porting cue of these machines for the evaporation of 

 mangoes, pineapples &c. But we have no doubt it 

 could be utilized as a tea drier. We shall read the 

 description carefully and let our readers know more 

 about the evaporator, the prices of which (minus I he 

 patented hood, which is a feature in Jackson's drier) 

 are from f 130 for 94 inch tray size to $600 for 

 60 inch tray size: say from R300 to R 1,300. 



March 17th. 



I narrowly missed seeing an American fruit evapor- 

 ator in operation in Australia, a iVlr. PuUeine having 

 introduced it and hsvine obtained prizes for fruit 

 prepared by its means. It is like and yet unlike the 

 tea drier. The wire net trays in the case of the latter 

 are pushed iuto a framework, and when the leaf in 

 the bottom tray is dry (in about 15 minutes) the tray 

 is taken out, refilled, and inserted at the top, the trays 

 coming gradually a step down until that which went 

 in at the top ends at the bottom. In the caso of the 

 evaporator, the rims of the trays form the walls of a 

 "tower," which ultimately reaches to a second story, 

 the stove being in a cellar. A tray full of fruit is put 

 over the heat for from 5 to 15 minutes ; it is then 

 hoisted by machinery to make room for another below, 

 and this process goes on until the tray first put in 

 and its successors reach and deposit their prepared fruit 

 on the upper loft. In the fruit curing it is of import- 

 ance that the moisture expelled from below should pass 

 through the successive layers, for the object is not 

 wholly to dry the fruit, but so partially to cook it, that 

 it will keep well. In the case of the tea leaf, of 

 course, the object is to expel every trace of moisture, 

 so every tray is finished off at the bottom in almost 

 immediate contact, a metal plate only intervening, with a 

 heat 280". In both cases there are two sections of trays, 

 there being a division down the middle. But while in 

 each section of the evaporator there are a score of 

 traj s there are but five in each section of .lackson's 

 Dryer. Each of the ten trays has a drying surface of 

 2 8" by 2' 9" or 7' 4" square, a total drying surface 



o'f 73" 4", which is capable of converting 60 lb. of 

 green leaf into 15 lb. of dry in 15 minutes. One of 

 the great defects apparent in Mr. Shand's machine is 

 that it has only one surface, instead of ten or any 

 number which can be secured in the drier or the 

 evaporator. This and the slowness of the drying process 

 as well as the necessity of employing two heating 

 agents (steam as well as fire) instead of one, seem to 

 militate against its extensive use in tea-drying, however 

 useful it may be for preparing cocoa and perhaps cin- 

 chona bark. To Mr. Sband's statement that surface 

 can be increased at will, the obvious answer is that 

 horizontal space may be so increased as to place the leaf 

 beyond the reach of the coolies who are manipulating 

 it. Cannot Mr. Shand dispense with steam and adopt 

 tiers of wire gauze trays ? But then would arise the 

 question of invasion of patents. When the model arrives 

 and is tried, I will be able to judge and report. 



As regards the American Evaporator, the apples pre- 

 pared by its means are pared and cores taken out by a 

 machine which is sold by the same firm. It is claimed 

 for the evaporator that it is equally useful for the 

 preparation of vegetables, in which case our Yankee 

 cousins might send us the material for "squash pie." 

 In one of the testimonials, we observe that "corn" 

 (maize cobs, of course) was one of the articles 

 subjected to the process of evaporation. We quote a 

 portion of the pamphlet which describes the mode in 

 which the minimum of fuel is made to produce the 

 maximum of heat : — 



To obviate this excessive consumption of fuel, and in 

 consequence, to render the drying more uniform and per- 

 fect, it becomes necessary to provide some means of in- 

 creasing the draft through the drying flue ; and to do this 

 cheaply, effectively and conveniently, we construct the 

 apparatus as follows : Over the stack of trays or over 

 the flue we locate a hood, the lower mouth of which may 

 be made of the proper size to envelope the upper extrem- 

 ity of the stack, and connect the upper mouth with the 

 chimney. This chimney is supported above the position 

 of the stack of trays, which stack, as it is gradually in-, 

 creased in height, approaches the mouth of the chimney 

 This arrangement leaves a clear space beneath the chim- 

 ney for manipulation of the trays, and the chimney is 

 not supported upon any casing for the trays such as im- 

 mediately surrounds them in previous forms of driers and 

 prevents immediate access to them. 



From the heater the smoke pipe is carried up into the chim- 

 ney just above the hood, and out at the top of the chimney, 

 or, at least, up into the region of the top. To secure the 

 best advantages, this smoke-pipe should be about centrally 

 located within the chimney, and it should be so arranged 

 as not to interfere with the convenient workings of the 

 drier. 



From this arrangement it will appear that the heat in 

 the smoke-pipe, which would otherwise be wasted, will be 

 imparted to the moisture charged air above the drier, and 

 this, in turn, will have a greater tendency to rise and 

 pass off through the chimney, including a more rapid 

 flow of air through the drying-flue, in accordance with 

 well-known principles of pneumatics. The desired increased 

 air-draft is thus economically produced, and the more 

 thorough and uniform drying accompUshed. By increasing 

 the draft in this manner — that is, after the air leaves 

 the contents of the trays — the condensation of moisture 

 upon the top tray is obviated, and leaves the fruit per- 

 fectly cured, from the fact that it has been dried in 

 the least possible time, without scorching, and the nat- 

 ural flavour retained. 



Ai'ound that part of pipe between the first floor and 

 its connection with the chimney, we place a jacket, the 

 purpose of which is to confine the heat which would 

 otherwise be radiated therefi-om, and to conduct this to 

 the chimney also, thereby aiding the draft within the 

 air-flue, and at the same time excluding the heat from 

 the work-rooms, which are upon the fu-st and second 

 floors. 



Around the hood is a canvas or other flexible curtain, 

 hanging down sufficiently far to envelope some of the 



