630 



Insecticides and Fungicides. 



and this nicotine must be released by mixing it with an alkali 

 or spraying soap (which is sufficiently alkaline) . Further, a 

 nicotine sulphate spraying solution can only be valued by the 

 percentage of free nicotine it yields and not by the perceiatage 

 of nicotine sulphate. It is therefore important to purchasers 

 of nicotine that they should have a statement from the seller as 

 to (1) whether the article is free nicotine or nicotine in com- 

 bination, such as nicotine sulphate, and (2) the percentage 

 of free nicotine in the article, or if the latter contains nicotine 

 in combination, the percentage of free nicotine which will be 

 produced on treatment with an alkali. 



4. Copper Sulphate.— Copper sulphate sold for use in a 

 spraying mixture shall contain not less than 98 per cent, of 

 crystalHsed sulphate of copper (CuSO^. 5HoO). 



Note. — No comment is needed on this requirement, as it is obvious that if 

 a purchaser needs copper sulphate for making a fungicide, he requires it free 

 from impurities such as " green vitriol." 



5. Soft (Potash) Soaps.— (a) Not less than 95 per cent, 

 of the total alkali present in soft — that is, potash — soap sold for 

 spraying purposes shall consist of potash. 



(b) Soft, or potash, soap sold for spraying purposes shall 

 bear a label giving separate percentages of (1) the fatty acids, 

 and (2) the resinous acids, which the soap contains. 



Note. — Soaps used for spraying are almost always " soft soaps," and 

 typically such soaps are made by the combination of potash with a fatty acid. 

 Some "soft" soaps may, however, contain considerable proportions of less 

 valuable forms of soap — as, for instance, that produced by the union of soda 

 with a resin acid. Potash being more expensive than soda, there is always a 

 tendency in the cheaper soft soaps to introduce soda-resin soaps, which have 

 the disadvantage of producing a most objectionable curd with water which is 

 at all hard, blocking the spraying tackle and reducing the efficacy of the 

 spray fluid. It is therefore essential that growers should be able to purchase 

 potash (soft) soap with the guarantee that it is reallj' made with potash, and 

 the knowledge that fatty acids have not been replaced by resin acids. 



6. Liver of Sulphur.* — (a) An article sold as " liver cf 

 sulphur " shall consist of a mixture of salts of potassium, 

 chiefly sulphides. 



{h) It shall conform to the characters and tests given in the 



* The Ministry is anxious that this recommendation should not in a];y way 

 discourage the use of the sulphides of sodium. Since the action of cither 

 potassium or sodium sulphide depends on the sulphur and not on the potassium 

 or sodium, it is undesirable to discriminate in any way against the sodium 

 compound. When the time should come for proceeding with the proposed 

 legislation this point will require further consideration in conjunction with the 

 industries concerned : in the meantime it is desired to present the lecommend- 

 ations as nearly as possible in the form in which they were agreed. 



