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TEE AORICULTUBAL JOURNAL. 



given off is easily perceptible by the 

 smell ; in fact, such a mixture forms an 

 efficient filling for smelling-bottles. From 

 this we can see that lime must never be 

 mixed with any manure containing am- 

 monia on pain of losing its most valuable 

 ingredient. This is the reason why 

 Thomas Phosphate (basic slag), which 

 contains free lime, should not be mixed 

 with sulphate of ammonia, and why it is 

 dangerous to put lime on a manure-heap. 



Sulphate of Ammonia. 



Almost the only form of ammonia com- 

 pound used as a fertiliser in this country 

 is the sulphate. This should be in the 

 form of ? pale bluish-white powder. 

 When chemically pure it contains 21'2 

 per cent, of nitrogen ; but a good com- 

 mercial sample will give about 20 per 

 cent., equal to about 24*3 per cent, of am- 

 monia. A rough test may be easily made 

 of its purity by placing a small quantity 

 on a piece of red-hot iron, when it should 

 almost entirely volatilise, or disappear as 

 vapour, as all ammonium salts will. Any 

 residue remaining is an impurity. It is 

 the most concentrated form of nitrogenous 

 fertilizer, and is thought to be most effec- 

 tive on strong clayey soils, but not so 

 suitable for those rich in lime, as a loss of 

 ammonia will probably ensue, due to the 

 action of lime already spoken of. For 

 cereals, potatoes, and turnips it has proved 

 valuable ; it may be mixed with bones, 

 superphosphate, and guano, and is the 

 commonest form of nitrogen compound 

 found in " special " fertilisers. Being so 

 rich in nitrogen, about 1 cwt. per acre is 

 usually sufficient to apply. 



Nitrogen in Analyses. 



If a chemist has to examine a manure 

 or a soil, one of the chief points he has to 

 report on is the amount of nitrogenous 

 substance it contains ; and in order that 

 the relative values of different manures, 

 etc., may be easily compared, he tells 

 us, as a general rule, how much nitro- 

 gen there is present, regardless of the 

 particular compound form in which it 

 may exist. He does not usually say 

 there is so much nitric acid, or so much 

 sulpluile of ammonia, and so on, but 

 lunii)B them all together and says there is 

 ho much nitrogen. But occasionally we 

 find that instead of this system he calcu- 



lates how much ammonia the nitrogen is 

 equivalent to, and reports that there are 

 present nitrogenous compounds equal to 

 so much ammonia. It will, therefore, be 

 useful if we can perform the calculation 

 for ourselves, so that we can compare 

 analyses arranged on these different 

 methods. From what was said above as 

 to the composition of ammonia, it will be 

 readily seen that to convert the percentage 

 of nitrogen into its equivalent of ammonia 

 we must multiply the former by || or 

 1-215 ; and vice versa, ammonia may be 

 converted into its equivalent of nitrogen 

 by multiplying by { f or -824. 



Questions. 



1. What are the chief constituents of 

 the air ? 



2. How can you distinguish between an . 

 acid and an alkali ? 



3. If you added ammonia to nitric acid, 

 what compound would you expect to be 

 formed ? 



4. If you used hydrochloric acid instead 

 of nitric, what would you get then ? 



5. How coufd you tell when you had 

 added enough ammonia to neutralise the 

 acid ? 



6. If a manure contains 8^ per cent, of 

 ammonia, how much nitrogen is that 

 equal to ? 



7. Why is it wrong to mix sulphate of 

 ammonia with basic slag and not with 

 bone-dust ? 



8. Could you prove that a piece of flesh 

 contains nitrogen ? 



Some observations made in France have led 

 to the conclusion that it is highly probable that 

 onions grown on beds that have been manured 

 with sulphate of potash will keep sound and 

 good for a much longer period than others of 

 the same variety grown on land where the sul- 

 phate of potash has not been applied. 



At a time when so much ambiguity prevails 

 concerning what sort of animal is required for a 

 British cavalry horse, ihe conditions which 

 govern the class of new York shows for " horses 

 suitable for cavalry service " are worth quoting. 

 The competitors must be geldings not under 

 four years old, from 15 h. 1 in. to 16 hands 

 high. They must be sound and well brtd, gentle 

 under the saddle, free from vice, with free and 

 prompt action at the walk, trot, and gallop ; 

 whilst they must weigh not less than 950 lb. or 

 more than 1,150 lb. 



