128 VETERINARY HYGIENE 



properties of the quicklime have been lost, and the substance is 

 converted into hydrate of lime. 



By mixing the slaked lime with the sand, and adding a sufficient 

 quantity of water, lime mortar for building purposes is produced. 

 Pure slaked lime has little strength as a mortar without the addition 

 of sand. The proportion of sand to lime, in preparing mortar, 

 depends entirely upon the characteristics of the slaked lime and of 

 the sand used. As pure slaked lime hardens on the surface by 

 absorbing CO 2 from the air, the unexposed parts of the mortar 

 will remain soft and unsuitable as a mortar. The addition of sand 

 permits the entry of the air, and enables the mortar to set into the 

 form of a cement with binding qualities. 



In preparing lime for plasterwork, lime shells are slaked in an 

 " ark," which is any form of enclosure or tank which will hold the 

 quantity to be slaked. Sometimes an " ark " is formed in a 

 plasterer's yard by enclosing a corner with sand, filling in the lime 

 shells and applying water in sufficient quantity to reduce the shells 

 to an inert and saturated condition to ensure thorough slaking and 

 prevent blisters and " blows " in the finished plasterwork. After 

 thoroughly cooled, the sand in required proportion is mixed with 

 the lime, and the whole left for from 4 to 6 weeks to sour, 

 or weather, before use. Ox or goat hair, or manilla fibre, in the 

 proportion of one pound of hair to every two cubic feet of " coarse 

 stuff," should be mixed with the plaster lime in order to bind the 

 material into position in the building. 



The plaster just described is used for the first and second coat 

 of all ordinary three-coat work. The third and finishing coat is 

 executed with lime-putty or " fine stuff." This is the resultant of 

 slaking the pure quicklime as described, but without the addition 

 of sand, the water being allowed to evaporate, leaving a white, 

 putty-like mass which forms the finishing coat in plasterwork. For 

 very fine work the fine stuff just described must be carefully run 

 through a sieve and protected from dirt. 



For executing urgent work or repairs it is often necessary to 

 use gauged plaster, which sets more rapidly than ordinary three- 

 coat work. Gauged plaster is executed with the addition of one- 

 fifth of plaster of Paris to the plaster-lime or mortar. This work 

 can be executed in two or three coats, due to the quicker setting, 

 but for good class work slow-setting, thoroughly-worked ordinary 

 three-coat plaster cannot be excelled. 



Cornices are usually run with plaster lime to which from 30 to 50 

 per cent, is plaster of Paris, which causes rapid setting and enables 

 mouldings to be run sharply and accurately. In the use of highly 



