192 EXPERIMEXTAL FARMS 



1-2 EDWARD VII., A. 1902 



the more or less complete conversion of the sulphide and other sulphur compounds into 

 sulphate of lime (gypsum), which as we know, is a valuable fertilizer especially for 

 soils deficient in lime. To this end, therefore, it is advisable to spread the gas lime, 

 or to place it in small heaps, on the field in the autumn, ploughing or harrowing under 

 the following spring. 



As an insecticide, pure and simple, its action of course will be more pronounced if 

 at once (without weathering) it is ploughed or harrowed into the soil ; but by so 

 doing there would be some danger of injuring vegetation. 



Naturally, gas-lime is variable in composition, and consequently it is difficult to 

 state the limit to which it can be safely applied, but the usual amount will be between 

 2 and 6 tons per acre, and speaking generally we should advise a trial with the lesser 

 quantity. In Holland it has been used freely on heavy clay soil to the extent of 2 to 

 1\ tons per acre. In England, applied in autumn from 2 to 4£ tons per acre. It is 

 stated to act injuriously if applied directly to grass lands during the growing season. 



An analysis of gas-lime made in the farm laboratory appears in the report of this 

 Division for 1890, to which is appended an account of the value of this material from 

 the standpoint of a fertilizer. 



NOTES ON INSECTICIDAL MIXTURES. 



The following information in answer to inquiries submitted through the Ento- 

 mological Division, is inserted as of general interest to fruit growers : — 



Proposed Mixture of Lime-wash and Soft Soap. — The correspondent wished to 

 know if the good qualities of these materials could not be obtained in the one mixture, 

 and thus half the labour of application saved. Experiments were made in the labora- 

 tory, using thin lime-wash and whale-oil soap, and the results obtained confirmed our 

 conjecture as to the unsuitability of the mixture. 



A curdy lime-soap is precipitated, which in our opinion would not be so effective 

 as the original (potash) soap. Further, we believe, the mixture would be found to 

 have very poor adhesive qualities. 



The Addition of Washing Soda or Lye to the Soft Soap solution. — We were asked if 

 there would be any advantage in adding lye or sal soda to the soft soap wash. 



There is no chemical reason against this practice, and the mixture would be 

 stronger, i.e., more caustic, than the soap solution alone. There must, however, be a 

 limit to the proportion in which lye could be so used, for if the mixture were too 

 caustic there would be injury to the bark. Naturally, one would expect a soft soap 

 solution, strengthened with lye, to be more effective as an insecticide than the former 

 alone or with washing soda. 



The relative value of Soft Soap and Whale-oil Soap in insecticidal preparations. — 

 It is scarcely possible to say from the chemical standpoint which of the two — soft 

 soap or whale-oil soap — would be the more effective, though we might expect that a de- 

 termination of the excess of free alkali present would give an indication in that direc- 

 tion. This, no doubt, varies somewhat in each sample. Whale-oil soap most probably 

 owes its virtue in a large part to its qualities as a deterrent, and in this respect it must 

 certainly be considered as more effective than a soft soap made with a vegetable oil. 



On the use of Sal Soda instead of Lime in the Paris green mixture. — In answer to 

 the inquiry: 'Can sal soda be used instead of lime in the preparation of Paris green 

 mixture?/ the following information is submitted: — 



When Paris green mixed with water (at the usual rates of 1 pound to 100-200 gal- 

 lons) is applied to certain classes of delicate foliage (as of stone fruits) a corrosive or 

 ' burning ' effect has been noticed to follow, the leaves showing decided marks of injury 

 as the insecticide dried upon them. This is due to a certain small percentage of free 

 (uncombined) arsenic. This injurious effect may be entirely overcome by the addition 



