376 FOREST PRODUCTS 



Succeeding the suspended iron kettle came the open furnace, built of 

 flat stones or brick with grates placed over them and space provided 

 for from four to six kettles. The next step was the use of the boiling 

 pans which varied in width from 30 in. to 3 ft., in length from 6 to 10 ft., 

 and only about 6 in. deep. These pans came into use about the middle 

 of the last century. In 1865 pans with partitions to produce an alter- 

 nating flow of sap were introduced and rapidly adopted. The latter 

 made possible the gradual flow of sap from one side to the other through 

 succeeding compartments until it finally emerged in the form of syrup. 

 This principle is incorporated in the modern evaporators, which have 

 been in common use for the past forty years and which are used in con- 

 nection with all of the larger commercial sugar orchards. They have 

 a capacity of converting from 25 to 400 gal. of sap into syrup in an hour. 



The modern evaporators are usually from 2 to 6 ft. in width, 4 to 8 in. 

 deep, and from 6 to 24 ft. long with corrugated bottoms to increase the 

 heating surface. The rate of flow through the compartments is obvi- 

 ously of the greatest importance. Most of the present models use 

 automatic regulators by which the flow of sap from the tank or reservoir 

 increases or diminishes with the heat underneath the pan. The evap- 

 orator is always operated now in a sugar house conveniently located to 

 the maple orchard. Its use will be more fully explained later in this 

 chapter. 



As the evolution of the modern evaporator came about in gradual 

 improvements, so the methods of collecting the sap and maintaining the 

 sugar grove progressed from time to time. At first the sap was gath- 

 ered in wooden buckets and carried by hand to the kettle or sugar house. 

 Then a barrel on a sled drawn by horses or oxen was used as larger groves 

 were tapped. The most modern improvements are exemplified in a 

 system of pipes which convey the sap directly by gravity to the storage 

 tanks along the roadside or to the sugar house. One large Adirondack 

 sugar bush used a narrow gauge railway for bringing the sap from the 

 woods to the sugar house. 



Another great advance in the industry has been in the cleanliness of 

 the methods of tapping, gathering and manufacturing of both syrup and 

 sugar and, therefore, in the purity of the product. At the present time, 

 covers or lids are used on the pails hung on the trees on most of the up- 

 to-date operations. Formerly rain, snow, leaves, twigs, pieces of bark, 

 etc., fell in. BoiUng was practiced in the open and here the same oppor- 

 tunity was afforded for impurities to fall in. The hghtest colored sugar 

 and syrup are only derived from the purest sap and by the use of the most 



