37 



is within about 8 inches of being full, then close the doors. The fire box 

 should be deep enough and the wood fine enough to allow for three or 

 four tiers of wood and still leave space under the pan. This is impor- 

 tant, as it allows the fire to roll over and over, giving off the utmost heat 

 to the pan. In firing the fuel shoulJ be thrown in very rapidly so as to 

 keep the doors open as short a time as possible, as the inrush of cold air 

 when the doors are open quickly cools the pan and delays the evaporation. 

 The nature of maple sap is such that by boiling there is a natural 

 cleansing of the product. A coagulation of albuminous matter first occurs 



Fig. 25. VIEW OF INSIDE OF SUGAR HOUSE 



and this rise 3 as a scum bringing with it other solid matter. As all sugar 

 makers are aware, it is highly important that this scum be removed as 

 it forms by means of a skimmer which resembles an ordinary house dust- 

 pan, having a somewhat longer handle and perforated bottom. 



After boiling has proceeded for a time the depositing of mineral 

 matter variously known as sugar sand, silica, malate of lime and nitre, 

 commences. 



This comes about by a concentration of the mineral salts to a point 

 when they will no longer remain in solution. By the time the syrup 



