82 The Spraying of Plants. 



years ago by Professor Taylor, the microscopist of the Depart- 

 ment, and more recently they have been made by several in- 

 dependent experimenters in Florida, but particularly by Mr. 

 Joseph Voyle, 1 an intelligent correspondent at Gainsville, who 

 uses kerosene, soap, and fir-balsam combined at a high temper- 

 ature and produces a permanent paste which he calls ' murvite,' 

 readily soluble in water. Recent experiments made at our re- 

 quest by Mr. Clifford Richardson, 'assistant chemist of the 

 Department, with ordinary soap, whale-oil soap, and both light 

 and heavy oils, also show that 20 parts hard soap, 10 parts 

 water, 40 parts kerosene, and 1 part balsam, produce the most 

 satisfactory results. . . . Mr. Hubbard's experiments would in- 

 dicate, however, that for insecticide purposes nothing equals 

 the milk emulsions which were first suggested by Professor 

 Barnard 2 during our work on the cotton worm at Selma, Ala., 

 in 1880, and though the use of ordinary emulsifying agents, as 

 various mucilaginous substances and the phosphates, lactophos- 

 phates, and hypophosphates of lime, may facilitate the making 

 of kerosene emulsions, we have not yet had them sufficiently 

 tested as insecticides, and for the present can recommend noth- 

 ing more simple and at the same time more available to the 

 average farmer than the permanent milk emulsion as produced 

 by Mr. Hubbard.' 



During the season 1881-82, Mr. Hubbard was making exper- 

 iments for the destruction of the scale insects affecting orange 

 trees. He made the milk emulsion only, and of varying 

 strengths. The following is the formula recommended at the 

 close of the season's work : 8 " Refined kerosene, 2 parts ; fresh, 

 or preferably sour, cow's milk, 1 part (percentage of oil 66|). 

 Where cow's milk is not easily obtained, ... it may be replaced 

 by an equivalent of condensed milk (Eagle brand) diluted with 

 water in the proportion 1 to 2. . . . In applications for scale 

 insects, the kerosene butter should be diluted with water from 

 12-16 times." 



Under date of Sept. 15, 1881, Mr. Hubbard writes to Dr. 

 Riley regarding the condition of the work on orange scale then 



1 See II. S. Dept. of Agric. Div. of Ent. Bull. 1, 19. 



2 For further details concerning W. S. Barnard's suggestion of an emulsion of 

 milk and kerosene, see The Official Gazette U. S. Patent Office, Vol. 59, No. 12, 1919. 



s Ann. Re/pt. V. S. Com. of Agric. 1831-82, 113, 114. 



