MAY, 1910.] 



414 



Scientific Agriculture 



cult to keep the , gelatinous precipitate 

 in suspension if more than a day old. 

 A method of using stock solutions is 

 outlined, and there are illustrations of 

 the mixing apparatus, but these do not 

 present any practical difficulty to a 

 pharmacist who bears in mind the fact 

 that the best precipitate is produced by 

 mixing the copper-sulphate solution and 

 the milk of lime when both are diluted 

 to the utmost the strength of the mix- 

 ture allows. If the Bordeaux mixture 

 is properly strained no trouble will 

 subsequently arise from blocking of 

 the spray-nozzles. In speaking of the 

 test of copper in Bordeaux mixture, we 

 note that Mr. Salmon parenthetically 

 refers to potassium ferrocyanide as a 

 poison. It is not usual to designate 

 those chemicals as poisons th^t are 

 administered in doses of 10 grains. 

 No additions should be made to the 

 Bordeaux mixture, treacle and soap 

 sometimes used being unnecessary. 

 Mr. Salmon objects to powder and paste 

 forms of Bordeaux mixture, as the re- 

 sulting liquid settles much quicker than 

 when the chemicals are combined in 

 dilute solution. The production of a 

 ready-made form of the mixture that 

 would be free from this objection is 

 worth investigating, a«, no matter how 

 explicity the directions are given for 

 making Bordeaux mixture, the number 

 of farmers who are able to car^y them 

 out successfully is small. With the 

 spread of scientific knowledge among 

 agriculturists this difficulty should dis- 

 appear. The article deals exhaustively 

 with the spraying-machines and nozzles 

 with which Brodeaux mixture is used. 

 The spray produced must be very 

 fine and " misty " or smoke-like : a hang- 

 ing "mist" or "fog" must be pro- 

 duced, which drifts over and through the 

 tree, and deposits on the surface of the 

 leaves excessively minute drops, which 

 when dry give the parts of the trees that 

 have been sprayed the appearance of 

 being almost uniformly covered with a 

 very thin bluish film or dust. Such a de- 

 posit is so intimately attached to the sur- 

 face of the leaf or fruit that it does not 

 readily wash off. The points to be con- 

 sidered about spraying-machines are 

 (1) the machine and its chief working 

 parts must be made of material which 

 the spray solution will not affect chemi- 

 cally, (2) the pump must be powerful 

 enough to maintain a pressure suffi- 

 cient for the particular nozzle used, 

 and (3) the build of the machine must 

 be suitable for use in the particular 

 plantations or orchards to be sprayed. 

 Many agricultural chemists aheady 

 undertake sheep-dipping or supply the 

 apparatus for the work. We see no 



reason why chemists should not in like 

 manner specialise in tree-spraying ap- 

 paratus or undertake the operation of 

 freeing or protecting fruit-trees from 

 agricultural pests. 



BARBADOS : REPORT OF THE AGRI- 

 CULTURAL WORK. 



General Conclusions. 



(Prom the Barbados Report of the Agri- 

 cultural Work for the season between 

 1905-1907, Imperial Department of 

 Agriculture, West Indies.) 

 From the preceding summary the 

 following conclusions may be drawn 

 from the results of this year : - 



(1.) The average yield of canes was a 

 fairly good one being 31*94 tons for the 

 whole field. 



(2.) An ordinary application of farm- 

 yard manure without the addition of 

 artificial manures produced a crop of 

 23 tons of cane per acre. 



(3.) This crop can be substantially- 

 increased either by a further large appli- 

 cation of farmyard manure or by the 

 application of artificial manures. 



(4.) The application of 20 tons extra of 

 farmyard manure gave an increased 

 yield of about 8 tons of cane per acre of 

 the value of $24*00. 



(5.) The most favourable result of the 

 application of artificial manure was 

 given by the plot that received 80 lb. of 

 phosphate as basic slag in January, 

 potash 60 lb. as sulphate in January and 

 nitrogen (as sulphate of ammonia) 15 

 lb. in January, and 45 lb. in June. This 

 plot gave about 40 tons of cane per acre, 

 an increase of about 17 tons of cane by 

 artificial manure. The value of this 

 increased yield was $51 "00, the cost of 

 manure was $15"36, and the net profit 

 $35-64 per acre. 



(6.) Minerals alone (80 lbs. of phos- 

 phate as superphosphate and 60 lb. 

 potash as sulphate, applied in January) 

 gave an increase of 6 tons of cane per 

 acre ; but the results of the phosphate 

 series and potash series leave it doubt- 

 ful as to whether this increase is due to 

 the phosphate or to the potash. 



(7.) The application of nitrogen in 

 addition to minerals gave an increased 

 yield ; 40 lbs. nitrogen as sulphate of 

 ammonia applied partly in January and 

 partly in June gave an increase of 3 

 tons canes. Net profit by the addition 

 of nitrogen $2'52. An application of 

 60 lbs. nitrogen as dried blood partly in 

 January and partly in June gave an in- 

 crease of about ti tons of cane, Net profit 

 by the application of nitrogen $8*28, 



