J. V. Eyre and E. S. Salmon .")(»7 



i. Iron sulphide, which has been favourably reported upon in 

 field experiments, proved on close observation to have, at a concentration 

 of 0-6 %, a remarkably ijuick fuiiL'icidal action on the Hop-mildew. 

 When made by a method which leaves a trace of ammonium sulphide 

 present it has proved to be quite harmless to foliage and is in a condition 

 which enables it to be applied as a fine spray. 



5. The presence of free alkali in solution is not the determining 

 factor in the fungicidal value of the alkaline sulphide solutions used. 



6. The proportion of sulphide-sulphur present is no index of the 

 fungicidal value of solutions of alkaline sulphides. 



7. It appears that the polysulphides contained in a solution of 

 yellow ammonium sulphide act fungicidally as such and not by virtue 

 of the sulphur which is def)osited when these compounds decompose. 



(Received December 21th, 1915. 



