500 



fall upon a portion of the leaf where there is no poison, growth may 

 yet be prevented, as will be readily understood by examining the 

 illustration, where the germination of spores c, d, e, and / has been 

 checked, because their sprouts have run against the poison. 



II 



- A. Fig. B. 



In the above illustration a careful drawing is given of two 

 different sprayings. In one case the leaf was sprayed for nine 

 consecutive seconds ; in the other case, also for nine seconds, but at 

 three different times of three seconds each, the leaf having dried 

 between times. The results are very different. Where the spray 

 was applied nine seconds continuously the drops have melted into 

 one another, and left wide, unprotected blanks amongst them (B). 

 It is evident, therefore, that Fig. A represents a more efficient 

 method of spraying than B, not because more poison has been 

 applied, but because it is in a finer state of subdivision. It will be 

 seen at once that if the spores a, b, c, d, e, f, g, h had fallen on A 

 instead of B their chance of growing would have been much 

 diminished. As it was, all but two spores were killed, These two 

 (a and b), having alighted in the midst of large areas free from 

 poison, were able to grow to their full extent. 



FACTS WORTH KNOWING. 



The moral of this teaching is, therefore, never spray until the 

 drops of the poisonous liquid drip down from the foliage ; but 

 spray rapidly, coining back on your steps spraying again rapidly, 

 and again once more, allowing time for the liquid to evaporate in 

 the interval. No more liquid will be used in spraying the area of 

 ground to be protected by this method, whilst the time employed in 

 spraying will be practically the same in each case, while the result 

 will be widely different. 



Two or three sprayings, at a fortnight's interval, are better than 

 only one, and one spraying better than none. Spraying early in the 

 season is much more efficacious than later. 



Trees will sometimes be injured by being sprayed on a very 

 hot and windy day : the best time to spray is either on a dull day, 



