GENERAL PRACTICE. MANURES. 49 



moistened with the contents of the sewage tank or urine from stables, and occasionally 

 turned to prevent its heating too much, the ammonia formed is absorbed by the mass, 

 and in time becomes converted into nitric acid. During fermentation organic acids, viz. : 

 humic, ulmic, and carbonic, form and combine with the ammonia ; the resulting salts, 

 being very soluble, are easily washed out, and a brown liquid oozing from manure 

 heaps, rich in nitrogen, may often be seen draining wastefully away. 



Fowl and pigeon manures are rich in nitrogen, containing from 1 to 4 per cent, 

 of ammonia, and when dried resemble guano ; a dressing of these tells very beneficially 

 on all fruit trees that require invigorating or feeding for swelling their crops. Bone- 

 dust contains nitrogen equal to 2J to 3 per cent, of ammonia. In steamed bones the 

 amount is rather less, but as these can be ground to a finer powder than either fresh or 

 boiled bones, the product is superior in effect to the more nitrogenous bone-meal. 



Guanos are rich in nitrogen. Peruvian is the best, and should contain 12 per cent, 

 of ammonia, and 25 to 27 of calcic phosphate. It is then valuable for fruit trees that 

 need assistance. For watering trees to enable them to swell off their crop to the best 

 advantage, 1 oz. to a gallon of water, or preferably 1 Ib, to 20 gallons, and for distribu- 

 tion as a surface dressing 1 Ib. per rod is a minimum, and 2 Ibs. a maximum dressing, 

 or \\ to 3 cwt. per acre. Fish potash-guano is excellent at the rate of 4 to 5 cwt., 

 and native guano safe and good 10 to 15 cwt, per acre. 



Nitrate of Soda. The nitrogen in nitrate of soda exists to the extent of 15 or 16 per 

 cent. ; 3 Ibs. of it are equal to 2 Ibs. of sulphate of ammonia. Its effects, through the 

 quick action of nitric acid, are telling on vegetation, and it is useful for fruit trees in 

 poor soils ; indeed, wherever nitrogen is wanted it may be applied. In wet seasons it is 

 soon washed away, but in dry seasons it is more enduring in its effects. It is considered 

 to favour the utilisation of phosphates by giving the plants greater power of attacking 

 them. It rapidly lowers the temperature of water, which must be borne in mind in using 

 it as liquid manure for strawberries, vines, or other forced fruits, and | oz. per gallon 

 of water is sufficiently strong. One to 1| cwt. per acre is an ample quantity for fruit 

 trees needing vigour, always using it in spring or early summer, and if a tree here and 

 there is sluggish in growth and needs a stimulant, nearly an ounce of the salt-like 

 substance may be sprinkled on each square yard of soil as far as the roots extend, and 

 this is at least equal to the spread of the branches. Nitrate of soda is open to adultera- 

 tion with common salt, the crystals being similar, and it should be purchased under a 

 guarantee of 95 per cent., which means it will only be 5 per cent, short of purity, 

 VOL. I. H 



