A. U. Lkk8 



357 



that gelatiiie, the essential body in glue, is insoluble in alkaline solutions 

 was not realized. Lime also appears to decompose glue, as a mixture 

 of the two becomes frothy and the glue loses its properties. The 

 following mixtures were tried with the results included in the following 

 table : 



None of these mixtures could be considered satisfactory. 



Various other substances were added to the ordinary lime wash 

 with the idea of obtaining a firmer coat. These were miscellaneous 

 in nature and may be included for convenience in one table as follows: 



Result 

 About as hard as lime alone 

 Decidedly soft coat probably due to 



the oil 

 Also gave a soft coat due to the oil 

 A soft coating due to the fat contained 



in the milk 

 Very soft and powdery coat 

 All gave flaky and soft coatings, the 

 softness increasing with the pro- 

 portion of cement 

 Less flaky than the cement mixtures, 

 but the flakiness increased with 

 increased proportion of plaster 



The failure of the cement was probably due to its drying before 

 proper setting could take place. Under ordinary conditions cement 

 is mixed with a quantity of water so that it has a chance of absorbing 

 some chemically before the mass dries. 



Methods of slaking lime. 



During the course of these experiments it was obvious that the 

 firmness of the resulting coat depended largely on the manner of slaking 

 the lime. An experiment was therefore started to find the method 

 that gave the best result. The usual way of slaking lime is to add 

 just sufficient water to allow chemical action to proceed, that is, it 



24—2 



No. Mixture 



(1) Calcium chloride 



(2) Solar distillate paraffin in emulsion in 



the lime 



(3) Solar distillate and aluminium sulphate 



(4) Various proportions of skim milk 



(5) Calcium chloride then waterglass 



(G) Cement in the proportions of 1 : 1, 1 : i, 



1.11.1 

 ^ • 31 ^ • -^ 



(7) Plaster of Paris in the proportions of 

 1.1 1.1 1.1 



i. . -H, 1 . TT, 1 . Vf 



