634 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



considerations, and the fact that in many sections of the State hme 

 sulphur is now the only remedy used against scale insects, and is fast 

 replacing Bordeaux mixture as a summer spray, have recently brought 

 it into great prominence. Experiments have been made to determine the 

 effect of magnesium oxide in the lime, and the conclusion is arrived at 

 that the principal objection to it is the reduction it causes in the 

 amount of calcium oxide in the spray, as it does not affect the amount 

 of sulphur going into solution, if enough of the lime is used to insure 

 the ratio of one part of calcium oxide to two of sulphur being main- 

 tained (p. 73). It is suggested that an approximate analysis of the 

 lime to be used should be obtained from the manufacturer, and then 

 such an amount used as will preserve the ratio of one to two. 

 Experiments have been made to determine the effect of storing the 

 lime-sulphur solution in contact with the sediment, and no deteriora- 

 tion has been noticed if properly stored when made according to the 

 formulae recommended (50-100-50, or 60-125-60), so that there is no 

 advantage to be gained in filtering the solution before storing ; but when 

 the solution is made according to a formula calling for an excess 

 of lime, there is considerable deterioration due to the separation of 

 some of the sulphur compounds in the form of crystals (p. 75). The 

 increase in soluble sulphur owing to re-heating before use is not 

 sufficient to pay the cost of the operation. (See Jouenal R.H.S., 

 vol. xxxvii., p. 262.)— A. P. 



Lime-Sulphur Sprays: Methods of Analysis. By J. E. 



Harris (U.S.A. Exp. Stn., Michigan, Tech. Bull. 6; Jan. 1911).— An 

 attempt has been made to modify the analytical methods with the 

 idea of securing greater accuracy and rapidity. The main difference 

 between the methods as described in the bulletin and those in common 

 use lies in the manner of effecting the oxidation of the sulphur com- 

 pounds and in the estimation of the monosulphide and total sulphide 

 sulphur, and the length of time required to make a complete analysis 

 of a sample of lime-sulphur solution is reduced from more than one 

 day to only a few hours. The manufacture and storage of home- 

 made solutions is also dealt with. (See abstract of Circular No. 10 

 ibove.) — A. P. 



Locust Destruction in South Africa. By C. W. Howard {Jovr. 



Econ. Entom., vol. iii., pt. iii., pp. 260-271 ; June 1910). — A very com- 

 plete account of the work done in South Africa towards the destruction of 

 the two species of locusts (Brown Locust, Pachytylus sulcicollis, and the 

 Red-winged Locust, Cyrtocanthacris septeinfasciata = Acridiuni purpuri- 

 ferum) which are pests there. Enormous progress in crop-saving has 

 been made and at a cost out of all proportion to the benefits obtained. 



Fungus infection has proved of no avail, but spraying strips of grass 

 in the path of the locusts with a mixture of sugar and arsenic has been 

 most effective. — F. J. C. 



