A. H. Lees 355 



Both gave good coverings and were more satisfactory than those 

 made with ordinary starch. 



With the idea of incorporating a fungicide Bordeaux mixture was 

 added, but it caused great thinning of the liquid. 



The same result was obtained when copper sulphate was added. 

 The addition of flowers of sulphur, with the same end in view, though 

 it caused no thinning was unsatisfactory as the dried coat showed 

 great tendency to flake. 



The cost of No. (2) of the above table is 2d. a gallon of which the 

 whiting costs l\d., the glue \d. and the farina \d. 



Owang to the expense of the whiting, due chiefly to the large quanti- 

 ties necessary to produce a thick coat, lime was again tried as the 

 covering material. The following mixtures were tried with the results 

 included in the table: 



Result 

 Poor covering 

 Poor covering 



Very good but flocculent and inclined to flake 

 Too thick but not firm enough 

 As thick but not coherent and flaking when dry 



In order to stop this flaking a mixture of lime and whiting was 

 tried with the idea that the different sized particles thus introduced 

 might interlock and so prevent the flaking: 



Lime Whiting Glue Farina Water 



14 7 1 1 80 



This mixture, though it appeared not to flake at first after a few days 

 did so. It was suggested that the addition of cressyllic acid which is 

 supposedly used in some distempers might give good adherence. 

 I, 2 and 5 per cent, added to the ordinary lime wash, however, gave 

 mixtures which flaked as badly as the control. 



Effect of aluminium salts. 



The extremely gelatinous nature of aluminium hydroxide is well 

 known and it w^as thought that by incorporating it with ordinary 

 lime wash adhesiveness might be obtained. Accordingly aluminium 

 sulphate was added. Its reaction with calcium hydroxide gives 

 aluminium hydroxide which thus becomes thoroughly well mixed. 



Ami. Biol. I 24 



