10 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY, 



In the open and on the large scale, it is, of course, possible to use 

 large charges, but in an enclosed garden in the neighbourhood of 

 walls, glasshouses, &c., I was advised not to exceed charges of about 

 two ounces from fear that foundations, &c., might be unduly disturbed. 



The trials that I have made were therefore designed to ascertain 

 what effect would be produced by small charges at a depth of three 

 feet, and I am much indebted to Mr. W. D. Gibbon for his advice and 

 assistance. Accordingly, patches were treated with 2 oz., i} oz., i oz., 

 and J oz. charges placed three feet apart. This was admittedly an 

 extravagant distribution, but the idea was to try what might be 

 called the intensive plan ; for, in giving a thorough opportunity 

 to the explosive, a small area in a garden may be treated at a rate 

 which would be absolutely prohibitive in cost when appHed to 

 the treatment of whole acres. Roughly speaking, the cost of fuse 

 and detonator may be put at about i^d. and the powder at id. 

 an ounce at retail prices ; so that on the estimate of the working 

 effect of a 4 oz. cartridge, which has been given above, a ten-foot 

 circle is worked for less than sixpence. At wholesale prices the 

 cost would be considerably lessened, for an ounce is estimated at 

 about ^d., and including fuse and detonators some four or five 

 2 oz. shots can be had for a shilling. At a cost of £S an acre, 

 somewhere about 700 i oz., 500 2 oz., or 330 4 oz. shots would 

 be available. 



With regard to the energy developed by cheddite, I am informed 

 that, allowing 50 per cent, loss of the total available energy, a 2 oz. 

 charge gives about 50,400 foot-pounds in the soil. If we contrast 

 this with the work put into the soil by the spade, taking the weight 

 of soil at 90 lb. the cubic foot and supposing each spadeful is raised 

 2 feet in the process of digging and breaking up a cubic yard, then 

 energy put into the soil would be 4860 foot-pounds, of course not 

 including the waste energy dispersed in lifting the spade itself. Thus, 

 where 2 oz. charges were used a yard apart in my garden, quite ten 

 times as much energy was put into the soil as the use of the spade 

 to a depth of only 3 feet would have done. 



Results with Poiatos. — One bed was planted with maincrop 

 potatos so that part of each row was on ground which had received 

 different treatment. The plot had had a dressing of stable manure 

 with some artificials the previous season, and a liming in the winter. 

 No further manure was given, partly to see what effect the extra deep 

 cultivation alone would do, and partly to avoid possible errors from 

 unequal distribution. The rows were 28 inches apart, and the tubers 

 put in 18 to 20 inches from each other. The varieties were * Sutton's 

 Rehance,' ' Crimson Beauty,' and ' Golden Perfection.' The last 

 (' Golden Perfection ') may be dismissed at once, for the growth and 

 crop were too irregular to be worth consideration ; it may be added 

 that the seed tubers were home saved, and that many of them failed 

 to undergo the natural process of autodigestion and were still quite 



