1890.] PARIS- AND SCHEELE'S GREEN 201 



" one man " fit for the purpose, Professor Allen Harker, 

 of the Royal Agricultural College, Cirencester. He would 

 do well, and as much desires the post as we wish to put him 

 in it, but then the Principal of the Royal Agricultural 

 College is very much set against his holding the post, as 

 well as his Professorship at the college. It is a great puzzle. 

 I have been doing my very best to help the Professor of 

 Agriculture a member of the appointing body to find a 

 suitable man, but what will come of it I do not know. 

 This is not private amongst friends, but it is not yet before 

 the public. Why, with you, I believe in a day you could 

 fill the chair. I think I could do all that is wanted, but 

 then, oh ! Shades of John Knox ! 



I am hoping each day to receive the copy of " Insect 

 Life " Professor Riley kindly sends me, and to see what the 

 Association of Official Entomology did at Washington. 



[Cablegram. ] 



December 28, 1889. 



Is not " Paris-green " the same as " Scheele's green," that 

 is, arsenite of Copper, not arseniate ? With us arseniate of 

 copper is a bluish powder ; please write. J 



January 20, 1890. 



I am exceedingly obliged to you for so kindly and 

 promptly replying to my enquiry about the arseniate. I 

 thank you most heartily, and Professor Saunders also, for 

 so very kindly taking the trouble to make me sure how the 

 matter stood. 



I have been taking a great deal of pains to make my 

 paper on the Paris-green as plain and sound as I can, but 

 whether I can induce the growers to use it is yet to be 

 seen. If any of your orchard operatives accustomed to 

 application of it should chance to be in England, I believe 

 that the best way to start affairs would be for his services to 

 be engaged at Toddington, and from a proper method of 

 spraying (and, without any doubt, its good effect), we should 

 then, I quite believe, make progress. If you should know 

 of any orchard workers being likely to come over, I should 

 be very glad if you would give me a line, and then if none 

 of my orchard applicants were disposed to engage him, I 

 would myself ask for a lesson and a lecture, and he " should 

 not lack his fee," as the old ballads say. Unless something 

 is done to rouse the good folks they will go on smearing 



1 An arseniate is a salt of arsenic acid, while an arsenite is a salt of 

 arsenious acid. 



