354 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
the fruit and seed. In all cases, therefore, where we grow a plant for 
the starch or sugar it lays up (as in the case of potatos, mangolds, 
and beet) , or where quantity and size of fruit are required, we must see 
that the plant can obtain sufficient potash. It also tends to heighten 
the colour of both leaves and fruit, and is therefore particularly neces- 
sary in the case of apples and tomatos. Fruit and grain will not 
swell without potash ; in fact, it works with phosphates in this 
function. 
Although an element so widely distributed, the sources of com- 
mercial potash are very few, and before the war the world's supply 
was almost entirely in the hands of Germany, owing to the rich 
deposits of Stassfurt in that country, from which sulphate and 
muriate of potash and kainit are mined. Nitrate of potash is some- 
times used, but, being a very powerful salt, care should be exercised 
in its application. Since the war British potash has been produced, 
and can now be obtained in a very suitable form for horticulture. 
The great potash value of ashes from the garden bonfire should 
always be remembered. 
These, briefly described, are the functions of the three essential 
ingredients of manures. It will be seen that they vary considerably, 
and while under normal conditions on a well-balanced soil ali three 
work together and assist one another, it is impossible to take an 
intelligent view of manuring without some knowledge of the effect 
produced by each of them. Different crops require more or less of 
one or other of them, and under certain circumstances one or two 
may be very necessary while another may be distinctly harmful. 
Forms in which they should be Applied. 
Having decided what you require of nitrogen, phosphates, and 
potash, for the particular crop you are growing, the next consideration 
is the form in which you should apply them. There are many forms 
of each on the market, and, as the results of the application of these 
various forms differ, the amateur must not neglect this point. 
His chief consideration will be whether he requires a lasting or 
a flushing effect ; if the former, a slow-acting organic manure must 
be used ; if the latter, a quick-acting mineral will best answer the 
purpose. For instance, in the case of the cabbage crop the grower 
will have decided rightly that nitrogen is required for leaf -production ; 
he will therefore put dung or crushed hoof or some similar lasting 
nitrogenous manure under the crop to carry it through the winter, 
but will top-dress in the springy with nitrate of soda or sulphate of . 
ammonia to get a quick early growth. Again, in manuring turnips 
superphosphate in the spring is a suitable dressing, but if phosphates 
are required for a fruit plantation, some form of bone phosphate 
(organic) should be used. 
It is obvious that in his decision as to the form in which he had 
best apply his manure the grower will be largely influenced by whether 
