FISHERIES, GAME AND FORESTS. 3 I 7 



to the heat under the pan; it cuts off the supply entirely when the fire gets low. By 

 this ingenious device there can be no scorching of the contents so long as there is 

 plenty of sap in the storage tank. 

 " The continuous flow of the cold, raw sap into the evaporator keeps the liquid in 

 that end at a much lower temperature than the contents at the further end. As the 

 stream flows from side to side in passing around or through the ends of the numerous 

 partitions the temperature increases, and the crude* liquid, by the time it reaches the 

 outlet, is ready to "sugar off." The steaming, boiling fluid is skimmed carefully of 

 the impurities which arise to the surface during its progress through the first compart- 

 ments, and the shallow stream, with its broad surface exposed to the direct action 

 of a hot fire, evaporates rapidly. 



In some evaporators syphons are used to convey the boiling liquid from one pan to 

 the next in order to confine the impurities and scum to the first compartments, where 

 they are most apt to rise to the surface as soon as the sap is heated. But the syphons 

 are unreliable and troublesome to manage, and so are being generally discarded. 



The color of the syrup is dependent largely on the depth of sap in the pans, and 

 the length of time that it is exposed to the heated surface of the evaporator. At a 

 depth of half an inch lighter colored syrup can be made than with a depth of 

 one inch. 



A thermometer is necessary in the progress of the work. It is placed in the 

 evaporator near the outlet. Granulation is indicated at 238 . At 245 ° hard cake- 

 sugar is made. At 219 the syrup will weigh eleven pounds to the gallon, and is as 

 heavy as can be made without granulating when cold. Some makers use a saccha- 

 rometer; but a thermometer is said to furnish the best results. 



The syrup contains a mineral substance called "nitre" or "sugar sand," which is 

 a malate of lime. As the season advances there is an increased amount of impurities 

 caused by the swelling of the buds ; the greater the quantity of these extraneous 

 substances, the higher the temperature required to make sugar. Syrup weighing 

 eleven pounds to the gallon will yield at 232 about eighty-two per cent, of sugar, or 

 eighty-two pounds to 100 gallons. At 242 °, about seventy-eight per cent, will be 

 obtained. The standard of quality as determined by the polariscope is eighty ; and 

 to make maple sugar that will stand this test the syrup will have to show a temperature 

 of 233 . 



The workman generally determines the proper time to sugar off by putting 

 some of the syrup in a saucer or shallow dish, and stirring it to find out whether it 

 will granulate. The boiling mass is then strained through cloths, and poured into 

 the moulds. The latter are usually brick-shaped, and the cakes weigh from two to 

 four pounds, this shape and these sizes being the most marketable. The utmost care 



