55 
acid, 6 lbs. potash, at 3s., £1 4s.; 12 ewt. concentrated super- 
phosphate, 45 per cent., containing 81 lbs. phosphoric acid, at 
18s. 43d., £1 1s. 4$d.; 14, ewt., potash sulphate, 54 per cent., 
containing 66 lbs. potash, at 12s., 13s. 23d.; cost of mixing, 
3s. 5d.; total, £3 2s, By this arrangement he gets the same 
amount of plant food for £3 2s. an acre that he did in the former 
case by paying £7. And further, suppose that he had applied 
the test plots to his soil, and had found it to be naturally rich 
enough in potash, he could knock off the 13s. 24d. for potash salt. 
But suppose he were to buy dried night-soil containing 3 per 
cent. nitrogen, 3 per cent. phosphoric acid, and 23 per cent. 
potash. This substance being not quite so soluble as in the 
blood manure and superphosphate mixture, he would require a 
larger quantity. Suppose he bought this at £1 15s. per ton, and 
used it at the rate of 1} tons per acre he would then be getting 
as follows:—14 tons dried night-soil, containing 100 Ibs. 
nitrogen, 118 lbs. phosphoric acid, and 83 lbs. potash, at £1 15s., 
£2 12s. 6d. Thus for 80s. an acre he would have got the same 
result as he did in the first instance for £7; but the cost of 
carriage and spreading on the land would have been three times 
as great. 
This question of cost of carriage is a very important one, and 
leads one to consider the advantage of concentrated manures. 
Take, for instance, the potash manures. Suppose we wish 
to buy a ton of potash, We may buy it in the form of 
kainit at £4 10s. To buy a ton of potash in this form we 
should have to pay £36, and the freight on 8 tons of material. 
But if we were to buy itin the form of highly concentrated sulphate 
of potash, containing 53 per cent. potash, we should have to pay 
only £22 16s., and the freight on 1 ton 18 cwt. The same in 
regard to superphosphate. If we wanted to buy a ton of soluble 
phosphoric acid we might do it by purchasing a low grade super- 
phosphate, containing 16 per cent. phosphoric acid, and selling at 
£7 10s.*; in this form we should pay for a ton of phosphoric acid 
£47, and freight on 6} tons of material. But if we were to buy 
it in the form of concentrated superphosphate, containing 45 per 
cent., and sold at £13 7s. 6d. we should have to pay only £29 
14s. 6d., and freight on 22 tons material. The cultivator who is 
a good business man will readily see the advantage of these con- 
centrated manures. 
Speaking of concentrated manures naturally leads us to con- 
sider the most bulky and least concentrated of all these plant- 
food suppliers, namely, farm-yard and stable manure. This 
manure varies in value, reckoned according to average market 
prices of plant food, at from 8s. 6d.up to 11s. a ton. Its average 
* But see note at bottom of table at the end of this lecture. 
