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A. H. Lees 149 



second that of paraffin. (Thus P.E. 2, 2 indicates Paraffin Emulsion, 

 2 % soap = 20 lbs. to 100 gallons of water and 2 % paraffin = 2 gallons 

 to 100 gallons of water.) 



P.E. 1, 1 gave superior results to 2 % of soap in that it gave better 

 wetting of the mildew. P.E. 1|, 1| was still better while P.E. 2, 2 gave 

 perfect wetting. P.E. 1, 5, though it nearly completely wetted the 

 mildew, was found to wet by means of paraffin instead of by aqueous 

 solution and so, though a cheaper mixture than P.E. 2, 2 would have 

 great danger of scorching fohage. P.E. 2, 1 stands intermediate in 

 wetting power between 2 % soap and P.E. 2, 2 and shows the influence 

 of introducing emulsified paraffin on the wetting properties of the hquid. 



There is no object in introducing greater quantities of either paraffin 

 or soap as P.E. 2, 2 gives perfect wetting. On the other hand the 

 behaviour of P.E. 1, 5 and P.E. 2, 1 show that it is not possible to reduce 

 the quantities of either without destroying the desirable qualities of 

 the mixture, P.E. 2, 2 is, therefore, the cheapest mixture that can be 

 used which at the same time has the highest wetting power. The 

 value of this 2 % emulsion lies not so much in its own kilhng power 

 as in the fact that it can act as a carrier, so to speak, for other fungicidal 

 or insecticidal bodies which, used alone, w^ould prove themselves in- 

 sufficient to kill. Thus liver of sulphur, used alone, has no great 

 controlling effect on American gooseberry mildew but, combined with 

 paraffin emulsion, has given promising results in a commercial scale 

 experiment undertaken by Prof. Barker and myself. In the direction 

 of insect control it also shows promise. While dilute solutions of 

 nicotine are without decided action on adult caterpillars or difficultly 

 killed beetles such as Byturus tomentosus, the Raspberry Beetle, it has 

 been found possible, at any rate on the small scale, to kill these by 

 uniting the same nicotine solution with 2 % paraffin emulsion. 



b 



