CtEeen viteiol. 177 



Linet agrees. To destroy charlock, Hitier estimates that 10 hectolitres 

 of a 10 per cent solution per hectare suffice (88 gallons per acre 

 suffice). Weiss also recommends this same quantity, but of 10-15 

 per cent strength. Schultz concluded after numerous tests that it was 

 necessary to use 15 per cent solutions, although young weeds already 

 suffer with a 2-3 per cent solution. It is necessary to apply this 

 treatment when the plants have only three or four leaves ; it is true that 

 cereals suffer slightly when young even when only a 7 per cent solu- 

 tion is used, but they soon revive and only grow afterwards with in- 

 creased vigour. To destroy young charlock and mustard 5-10 per 

 cent solutions suffice, but to destroy all weeds 15 per cent solutions 

 must be used. Wallflower requires a 10 per cent solution in the begin- 

 ning of vegetation. Before spreading green vitriol on a field the age 

 and sensitiveness of the plant must be taken into account. It is best to 

 proceed thus : The solution of green vitriol is conveyed to the neighbour- 

 hood of the field and sprayed by a spraying machine or a watering- 

 cart. The best time to treat weed-infested fields is just before the weeds 

 rise up into stems, i.e. when they have four to six leaves. It is well 

 to spray in fine weather, which by concentrating the solutions on the 

 surface of the leaves increases the effect. To free fields of grain chemi- 

 cally from charlock, advantage may be taken of the dew to spread finely 

 pulverized green vitriol at the rate of 200-300 kilogrammes per hectare 

 (176-264 lb. per acre). If rain intervenes after green vitriolizing, its 

 effect is lessened or destroyed. But even in that dose and under that 

 form green vitriol is not so efficient as a 4 per cent solution of blue 

 vitriol at the rate of 800-1000 litres per hectare (70-88 gallons per 

 acre). A man is capable of vitriolizing a hectare (2^ acres) a day ; 

 10 hectolitres (220 gallons) of green vitriol solution, that is to say, 

 100 kilogrammes (2 cwt.) of this salt suffice per hectare (88 lb. in 88 

 gallons per acre). The total cost of the treatment may be estimated 

 at 10 francs (8s.) the hectare (say 3s. 2|d. the acre). There must be. 

 no hesitation in applying this treatment, which while freeing the fields, 

 from encumbering weeds supplies it with a new element as an aid 

 to growth. From Steglich's comparative tidals green vitriol has no 

 advantage over such metallic salts as muriate of potash, nitrate of 

 soda, and sulphate of ammonia, which whilst destroying weeds are 

 good manures. However, we believe, that green vitriol is superior to 

 these salts by its anticryptogamic properties. 



Destruction of Moss. — 1. On Meadows and on Lawns.— Mosses^ 

 which invade all lawns, and diminish the yield of many meadows, 

 may be readily destroyed by green vitriol. Their affinity for water 

 is such that they absorb in large quantity the green vitriol distributed 

 in solution. The extreme limits to employ per hectare are 250-500 

 kilogrammes of green vitriol (2-4 cwt. per acre). It is well to 

 spread the distribution over several applications, especially when the 

 meadow is badly choked up with moss. Noffray advises not to go 

 beyond 100-150 kilogrammes per hectare (88-132 lb. per acre) in each 

 of these applications. If gi-een vitriol is used in crystals, it is necessary 

 to choose fine weather to spread it after a strong dew, during or after 

 rain. If green vitriol is used in solution in watering-carts, any time 



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