Vol. XII. No. 292. 



THE AGllICULTURAL NEWS 



213 



to be the ma.\imum cost. It is pointed out that if fruit 

 alone is sprayed the cost will be reduced by one-half or 

 two-thirds. 



In conclusion Mr. Rorer state.s that in Trinidad an 

 increased number of planters are each year becoming satisfied 

 that a direct profit is to be obtained by careful spraying. 

 The general experience seems to be that if the profitable 

 nature of the operation can only l)e demonstrated conclu- 

 sively, proprietors are only too glad in take it up. 



THE KILN-DRYING OP GRAIN. 



Owing to the great interest shown in the West 

 Indies concerning the drying of grain, especially 

 Indian corn, a letter was addressed recently by the 

 Imperial Co.nmissioner of Agriculture to the Chief 

 of the liureau of Plant Industry, United States 

 l)epartmcnt of Agriculture, asking for information as 

 to the process of curing or conditioning grain known 

 as kilnd-rying. As a result, communications embodying 

 important facts on the subject have lately been received 

 from three firms who manufacture drying machinery 

 employed in this conne.\-ion, and this information has 

 been included in the following article. 



The process of kiln-drying has for it-j piincipal objeot 

 the removal of a certain amount of the moi.-mre contained in 

 grain in order that it may not sutler from fermentation, 

 sprouting, and the development of saprophytic fungi — the 

 latter producing mildew and mustiness while the grain 

 is in storage or in transit between the time of reaping and 

 its receipt by the consumer. 



In northern temperate climates during former years, 

 maize and other grains have in small quantities been 

 cured in the field and in barns without the use of artifi- 

 cial means of drying, with only occasional losses resulting 

 from the excess of moisture : but when produced in enormoux 

 quantities, as in the case of the grain larras of the United 

 8tates and the British Xorth-West, and when rec-ived and 

 stored in the great grain elevators, it becomes necessary to 

 resort to some means of protecting the seed from the natural 

 consequences of the presence of large amounts of moisture. 



'i'he principle involved in the kilns or driers is bas»d on 

 the well-known facts that air may, by cooling, be divested of 

 a very large proportion of its moisture, and that if this dry, 

 cold air is heated to a high temperature, it will re absorb 

 a large amount of moisiure very rapidly on coming into 

 contact with damp or wet objects, which are capable of 

 giving up their moisture. 



The driers are generally installed in a building specially 

 designed and used for the purpose The essential parts are: 

 (1) the machinery necessary for drying the air by cooling it, 

 for heating it again and for forcing it througk the grain; 

 {'2) the drying chamber in which the grain comes into contact 

 with the hot, dry air; (3) the cooling chamber where the 

 grain, heated by contact with the iiot air, is cooled to 

 a normal temperature by currents of cold, dry air; and 

 (4) the machinery necessary for moving the grain from 

 place to place. 



The usual arrangement is to have, at the top of the 

 building, a ' garner ' which receives the material to be treated ; 

 beneath this is the drier, and beneath this, in turn, is the 

 cooler. The grain is transferred to the garner, and from this 

 point it passes by means of the necessary spouts, by gravity, 

 to the heater, then to the cooler and then to the carriers by 

 which it is transported from the kiln. 



The details of the ap|)licatiou of the hot and cold air 

 to the grain in the drier and the cooling chamber vary in, 

 different makes of machinery. In some of these machine* 

 the grain passe^ in a continuous How through the hot air 

 into the cool, the speed of this process being regulated so 

 that the desired result is obtained. In others, the drying 

 chamber is charged with grain, which at the expiration of 

 the necessary period of time, is passed on to the cooler. 

 The drier is then again charged. These kilns range, in 

 capacity, from a few bushels to several thou.sand per hour. 



In addition to removing the moisture which is naturally- 

 contained in grain insufficiently cured, kiln-drying may be- 

 resorted to for the purpose of conditioning grain which has 

 become wet by accident, an 1 for destroying insects and 

 fungi, thus often improving its quality and ettecting a saving: 

 to growers or dealers. 



Seed which has been kiln-dried may be used for [ilant- 

 ing, since experiments conducted by the officers of the 

 Bureau of Plant Industry (see Bulletin No. 100, Part III, of 

 that Bureau) show that the process of kiln-diying does not 

 impair the power of germination of the grain (wheat in the 

 trials reported) but rather increases it. 



Under ordinary circumstances, air-dried grain contains 

 an average of 14-1-5 percent, of moisture: any excess over 

 this percentage is removed by the process of drying — in fact, 

 the moisture content is usually reduced to something below 

 this, say, to 11 or 12 per cent., while it may be reduced to aa 

 amount as low as 8 or even 7 per cent. The greater propor- 

 tion of the moisttire is, of course, removed in the drier while 

 the grain is in contact with the current of hot air, but 

 a certain appreciable amount is got rid of in the cooler bj- 

 the cold air, which, having been divested of most of its 

 moisture, absorbs what it can as it is warmed by contact 

 with the hot grain. 



In order to effect the proper drying, the grain has to 

 be subjected to a temperature of from 100° to 200' F. A. 

 temperature of 140° to KiO' F. maintained for a short 

 time is fatal to most, if not all, of the insects and fungi 

 which are likely to infest grains, while, as is already stated, 

 the power of germination of the grain is not injured by 

 this amount of heating. 



Ib their application to the needs d the West Indies- 

 these drying machines would probably be used for drying: 

 Indian corn so that it uiight be succe.ssfully stored, and for 

 preventing insect attack on the stored grain, since any 

 attack or infestation by grain insects eould be remedied by 

 passing the grain through the driers 



The names of the firms that have provided infonnatior> 

 in this connexion are. The Hess Warming and Ventilating 

 Co., 708 Tacoma lUiilding. 131 La Salle Street, Chicago^ 

 The Morris Grain Drier Co., 51 Chamber of Commerce, 

 Milwaukee, Wisconsin; and the Macdonald Engineering Co.,. 

 549.553 Monadnoek Building, Chicago. 



An abstract appears in the Joiiruil of the Chemical Suc- 

 itty for May 1913, describing the changes which occur in the^ 

 coagulation of the latex of lleivi In-dsiliinii/i when this is left 

 exposed to the air. It appears that the coagulation is brought 

 about by an enzyme (probably a protease). Anaerobic 

 decomposition occurs in those portions which are out of 

 contact with air, and the presence of an o.xydase is indicated, 

 to which the name 'hevease' is applied. A fourth factor 

 consists of changes which occur in the presence of oxygea 

 (aerobic). These give ri.se to an alkaline mucus which. 

 causes the latex to become milky. 



