240 Winter Cover Washes 



caustic soda and the solution added. This gave a much softer coat 

 than the control. Resin therefore was not tried further. Table I (2). 



Casein was added during slaking of the lime. It is soluble in alkalies 

 so that a good mixture could be obtained. The resulting coat was, 

 however, soft and useless. Table I (.3). 



Dried dung was used as a source of humus bodies and was added 

 either immediately to the slaking lime or after a preliminary maceration 

 with caustic soda. In both cases the mixture was unsatisfactory. 

 Table I (5). 



The use of dung suggested the possibility of increasing adhesiveness 

 by incorporating some fibrous substance in the same manner that hair 

 is used in plasters for house walls. At first filter-paper was used and 

 afterwards newspaper. In both cases the paper was first treated 

 with caustic soda and macerated and then the pulp was added to the 

 slaked lime. 



A considerable number of mixtures of different strengths both with 

 and without the addition of starch were tried. On the whole the fibre 

 decidedly improved the coat as it did away with the tendency to 

 rlakiness, though the addition of caustic soda seemed always to increase 

 the softness. The method therefore of washing the pulp free from 

 caustic soda was tried and the resulting coat was certainly harder. 

 Some of these mixtures (Table I (6)— (12)) were tried outside (Table II), 

 but the results were disappointing as all were washed off in a com- 

 paratively short time if subjected to heavy rain, and none of them could 

 be considered satisfactory. This being the case it is not necessary 

 to enter into details of their manufacture. 



The last mixture of Tables I and II containing boiled linseed oil 

 might have given good results if it had been possible, economically, 

 to have used larger quantities. Its expense, however, ruled it out. 



Effect of alkalies on glue solution. 



The statement is made in the text-books that gelatine, the essential 

 body in glue, is insoluble in alkalies and that gelatine or glue should 

 not be used in spray fluids where free alkali is present. 



This Eact explains why mixtures of lime and glue were utter failures. 

 Not only have they no sticking power but the mixture gives a very 

 thin coat, very much thinner in Eact than the same quantity of lime 

 without glue would have given. No doubt caustic lime has an energetic 

 action on glue. The mixture gives off bubbles of gas indicating that 

 the glue not only becomes insoluble bu1 is decomposed at the same 



