CARBON BISULPHIDE. 75 



soil. WorkiQg on a large scale steam pumps carry the sulphuretted 

 water several kilometres (kilometre = 0-625 mile) by means of a 

 galvanized iron pipe. The average amount of sulphuretted water for 

 each stock is 20 litres (4-4 gallons), and the solution contains 0*5 per 

 cent of sulphide in summer and O'7-l per cent in winter. The soil 

 should be returned to its place as soon as possible after treatment. 



Insecticide Irrigations. — These examined and recommended by 

 Duponchel represent the most improved and rational system. Under- 

 ground irrigation, already very efficient in itself especially when manure 

 is added to the water, appears to be a method of treatment that can 

 be usefully applied in the treatment of the vine attacked by the 

 phylloxera. But although the ordinary treatment enables the state of 

 diseased vines to be improved, it could not in itself constitute a sufficient 

 remedy to kill the phylloxera and annul the disastrous effects of that 

 insect. Insecticide irrigations have a very salutary effect on vines and 

 fulfil the end in view. Carbon disulphide cannot, in fact, suffice by 

 itself alone to re-establish the health of a diseased vine during drought, 

 or when root growth is stopped. To attain this salutary effect it is 

 necessary to follow up the injections of sulphide, which in destroying 

 the phylloxera suppress the evil by an underground iri-igation which 

 causes the effects to disappear by fortifying the roots and giving new 

 vigour to the vine. It is better to combine the two treatments in a 

 single one and to apply simultaneously to the plant, along with the 

 water carbon disulphide and the necessary manures. This method of 

 diffusing the insecticide throughout the whole depth of the soil, in a 

 dose which it is known cannot injure the plant, produces an excellent 

 effect. The irrigations ought to penetrate 20-24 inches into the soil. 

 They require 1000 cubic metres of water per hectare, say 100 kilo- 

 grammes (88 lb. per acre) of sulphide, which represents 30 cubic 

 metres (6600 gallons) of sulphide vapour (2640 gallons per acre). A 

 stronger dose would injure the vine, especially during the epoch of vegeta- 

 tion, which lasts eight months. Insecticide irrigation is differentiated 

 from the sulphide treatment by the fact that the first can be applied in 

 the spring, in summer, and in autumn without prejudice to the plant, 

 whilst the latter can only be done during the repose of vegetation. 

 The irrigation water is brought to the culminating point of the vine- 

 yard to be treated. At this point it is mixed with the carbon disul- 

 phide in a tank, called the bubbling tank, and arranged so that the 

 water chai-ges itself with carbon disulphide without being able to carry 

 away with it what has not been dissolved. The same bubbling 

 apparatus used to dissolve the sulphide may serve for dissolving 

 the manures, so that the water entrains them and distributes them 

 throughout the whole extent of the diseased vineyard. To produce 

 good results the irrigation should be underground and the surface of 

 the soil should be maintained constantly dry and friable by tillage or 

 by hand hoeing, carried out after watering, and renewed each time 

 that rain has strongly packed the soil. To secure good underground 

 distribution it is necessary to lighten the soil by tillage and to open 

 around each stock a small ordinary stripping basin. These basins 

 are connected with each other so that they can be filled in succession. 



