736 Journal of Agriculture, Victoria. [10 Deo., 1918. 



increases solubility and adhesiveness. Treacle usually contains about 

 half its weight of uncrystallizable sugar; it should be free from glucose. 

 Sugar may be substituted for treacle, about half the weight being 

 necessary. 



Sugar Bordeaux, containing smaller quantities of treacle (or 

 sugar), ha5 sometimes been recommended; according to Gastine, how- 

 ever, Ferret's original formula (1 gallon treacle to 50 gallons mixture) 

 should be retained in order to obtain a complete measure of adhesive- 

 ness. 



It is sometimes claimed that the addition of sugar or treacle enables 

 Bordeaux mixture to remain in good order and fit for use for several 

 days after its preparation, a point which is, however, of little importance, 

 since the preparation of fresh mixture for each day's spraying presents 

 little difficulty if the directions detailed in last issue be followed. 



Soap. — Lavergne was one of the first to recommend soap mixtures, 

 concerning which very numerous articles have appeared in the French 

 viticultural press during the past twenty years. Lavergne does not 

 claim to be the inventor of the method; he recalls* having seen trials 

 of soap Bordeaux as early as 1894, though without any very striking 

 results. He relates how Dr. Mangin, in 1896, drew his attention to 

 the value of soap for the preparation of a mixture capable of 

 thoroughly wetting all vine surfaces. The first season's experiments 

 were not altogether satisfactory, but further trials in 1897 led to the 

 discovery of a mixture of similar composition and consistency to copper 

 soda, and with satisfactory wetting and adhesive power. 



The soap nsed was not that of Marseille (white soap), the basis of which is 

 oil and soda, but the jjreen or black soap prepared by means of caustic potash 

 solution and the oils of colza, rape, &c. (this would, no doubt, be a soft soap). 

 Tliis soap is obtainable commercially in the form of a stiff paste; it has the 

 advantaofe of being cheaper and more readily soluble in water than ordinary 

 Marseille soap. 



The formula, which was employed on a large scale, was as follows: — ■ 



Black soap, 1,000 grammes (2.2 lbs.). 



Copper sulphate, .500 grammes (1.1 lbs.). 



Water, 100 litres (22 gallons). 

 The copper sulphate is dissolved in a few litres of water. The soap is separately 

 worked up with a little water, in small lots at a time, by means of a spatula. 

 When quite fluid, it is thoroughly stirred into the bluestone solution, and made 

 up with water to the final bulk. 



Since Lavergne's first communication numerous aoap-Bordeaux 

 formula have appeared, into the composition of which many very 

 different kinds of soap have been made to enter. We thus have Bordeaux 

 mixtures with ordinary soap and with soaps made from linseed oil, 

 castor oil, &c. Rosin soap has also been largely used for the purpose. 



Vermorel and Dantony have conducted a considerable amount of 

 research work in connexion with soap mixtures of recent years, and 

 have communicated numerous notes, describing their results, to the 

 French Academy of Science. One of their most important recommenda- 

 tions is to use soap as rich as possible in oleate of soda, and free from 

 excess of soda carbonate and alkaline hydrates. Stearate of soda, which 

 is plentiful in most soap powders, should be avoided. It increases 

 surface tension to a noticeable extent, and reduces the solubility 

 co-efficient. 



* Revue de Viticulture, 26th June, 1897. 



