168 SCIENCE AND FRUIT GROWING 



a i per cent, solution was found to do so ; to allow a safe margin, 

 the strength finally recommended was 2j per cent. 



The results with lime, when used as a milk containing 10 per 

 cent, of quick lime, did not compare well with those with the 

 2 per cent, soda solution, the destruction of moss amounting to 

 .only 50 per cent. ; but the action of the lime was found to be 

 enhanced, up to 90 or 100 per cent., by the addition of solar 

 distillate, the oil, no doubt, coating the particles of lime, thus 

 preventing them from becoming rapidly carbonated, and so pro- 

 longing their caustic action on the trees. A 10 per cent, solution 

 of common salt or of calcium chloride was found to be quite 

 ineffective in destroying moss. 



Some examination was undertaken of the action of various 

 substances in improving the adhesive powers of lime, and of 

 preventing it from flaking off the trees after application. The 

 directions in which success was sought were : (i) the addition of 

 some soluble substance of a sticky or viscous nature, such as 

 glue, size or treacle ; (2) the addition of an oily substance, such as 

 paraffin or rosin ; (3) mixing the lime with a fibrous substance, 

 such as wood pulp, which might possibly act in the same way 

 as hair does in plaster ; (4) adding something which would bring 

 about a slow chemical action in the wash, resulting in the forma- 

 tion of an insoluble substance, which, being formed in situ, 

 might act as a cementing agent between the rest of the solid 

 and the trees ; sulphur, sodium silicate, and the sulphates of 

 iron and copper were tried; (5) the effect of the addition of 

 common salt to the lime ; this was examined, not because it 

 was anticipated that any good results could follow from the 

 presence of a soluble and chemically inert substance, but because 

 such an addition had been persistently recommended. 



In one series of experiments the various washes were applied 

 to similar apple twigs, which were then left exposed in a vertical 

 position for four weeks in July, during which time a considerable 

 amount of rain fell. In another series, lead pencils were similarly 

 treated, and exposed for two months dating from October 15. 

 After exposure, the amount of solid left adhering to the twigs or 

 pencils was determined by chemical analysis, as well as by 

 estimation based on the appearance presented by them. 



The strength of the wash used was in all cases i part of quick 

 lime, slaked, and then mixed with 4 parts of water. 



The general conclusions were, that none of the substances 

 examined satisfactorily prevented the flaking off of the lime from 

 the trees, but a considerable improvement in the adhesion of the 



