181 



If signs of " gumming" are observed in Citrus trees, to the abov^ 

 mixture should be added ^ lb. of Flowers of Sulphur. The mixture 

 adheres to the trunks and branches of trees for a considerable time, 

 but when it peels off, the bark b3neath will be found to be p)rfectly 

 clean and free from pests, both animal and vegetable. 



It must be remembered that such remedies as the one here recom- 

 mended cannot be expected to be permanently effectual, unless proper 

 cultural methods are adopted, so that tbe trees and plants are kept in 

 a healthy growing state.. Healthy trees are not often attacked by 

 insect pests. 



RULES FOR VALUING MANURES. 



The essential constituents of manures are the nitrogen, the phos- 

 phoric acid, and the potash. The Artificial Manures Act of 1897 re- 

 quires that vendors shall furnish with artificial manures, sold in any 

 quantity above half a hundredweight, an invoice certificate showing 

 the per cent, of nitrogen, phosphoric acid, or potash contain.ed in the 

 manure. The Act does not oblige the venior to confine his certificate to 

 a statement of these three ingredients ; but it is aivisable that he should 

 do so, for anything else can only be regarded as so much paddings 

 which tends to confuse the purchaser All manures that have any value 

 as plant-feeders contain one or more of these three important pUnt- 

 foods nitrogen, phosphoric acid, and potash It is these plant-foods 

 that give value to the manures ; if the manures contain more of these 

 plant-foods they are more valuable ; if they contain less, they are less 

 valuable. Anything else that they contain besides these plant-foods 

 is of little or no value, and is generally to be regarded as so much dead 

 weight, decreasing the value of the manures to the extent that they 

 raise the cost of carriage. 



The following is a sample of an advisable form of statement or an 



invoice certificate : 



Nitrogen (as sulphate of ammonia) . . 5 per cent. 



Phosphoric acid-water soluble . . 4J " 



" citrate soluble , . 2 " 



insoluble .. 1 



Total phosphoric acid • , 7J " 



Potash (as potash chloride) . • 6 " 



Such a statement contains all that is essential and nothing that is un- 

 essential ; there is nothing in it to confuse the purchaser, and from it 

 the purchaser can, if he knows the money value of 1 per cent of each 

 ingredient, readily and quickly find out the real value of 1 ton of the 

 material. 



