34 THE COMMERCIAL AND AGRICULTURAL 



phate in localities where bone materials exist in large quantities 

 in the soil ; in other words, when they can carry on their trade 

 in a very rich part of the country, they will meet with quite as 

 much success as manufacturers selling superphosphate containing 

 a high percentage of phosphate. 



The first questions for the farmer to ask himself are, what will 

 answer my purpose best? what will give me a good crop ? and 

 what manure gives me the best return ? and, having settled these 

 questions, I think he should then ask, what ought I to pay for 

 the manure which has answered my purpose ? I beg to direct your 

 attention, in the next place, to a few more conditions which 

 influence the efficacy of manure. If you use a top dressing 

 of guano, or nitrate of soda, too late in the season, upon wheat or 

 oats, it hardly produces any effect. I would not use a top dress- 

 ing for wheat later than February. On clay soils it may be advisa- 

 ble to use it in autumn. When used late in spring, guano, 

 nitrate of soda, and similar manures, do not produce any great 

 effect; while, when the same manures are used at the proper time, 

 they produce a most beneficial result. The time of application 

 then greatly influences the efficacy of manure ; but not only the 

 time, but also the mode in which the manure is applied. If you 

 use a concentrated manure like guano, in an imperfectly powdered 

 state perhaps with all the hard lumps in it you find in the 

 bags which you get from the manure merchant it does not 

 produce that effect which is realised by crushing and sifting it, 

 and perhaps mixing it with salt or sand. You have no doubt 

 seen it recommended to mix salt with guano. Some persons 

 think salt has the effect of "fixing" the ammonia, but the 

 " fixing" of ammonia by salt is all nonsense, for the simple reason 

 that guano contains scarcely any free ammonia. The result of a 

 number of experiments gave me as the amount of carbonate of 

 ammonia in guano hardly three quarters per cent., a very small 

 quantity indeed. Allow me to suggest to you to mix guano with 

 oil of vitriol. You will find that the peculiar smell is by no 

 means destroyed by sulphuric acid, which would be the case if it 

 were due to ammonia. People run wild with the idea that every- 

 thing which smells is ammonia. They talk of ammonia and 

 carbonic acid, and then think they have done a great service by 

 introducing chemistry to the notice of the practical farmers ; but 

 such men do a great deal towards bringing that science into dis- 

 repute. Well, now, why does guano act so well when mixed with 

 salt ? Chiefly, I believe, because you cannot mix it without 

 breaking down the hard lumps, and thus distribute it more 

 equally upon the land, and everything in farming depends upon 

 the equal distribution of manuring substances. I would say, mix 

 the guano with earth (if dry), burnt clay, sand, or salt ; but this is a 



