THE PRODUCTION OF MAI'LK SIRUP AND SUGAR. 41 



tree, they should ho boiled in water once or twice, then allowed to 

 dry thoroughly in a warm place before storing them in a box. The 

 collecting buckets, hauling tank, and storage tank should be painted 

 on the outside, and if of wood on the inside. 



The evaporator should be cleaned out, the ashes removed, and a 

 coat of asphalt paint or red iron paint given to the exposed metal 

 parts. 



The scale in the pans is best removed by boiling water in them 

 and then using a fine wire brush. The scale, known as "sugar 

 sand," "silica," or "malate," is a nearly pure malate of lime, the 

 mineral matter of the sap that on concentration has been deposited 

 in the pans when its solubility in the liquid has been reached. It has 

 no particular economic use; some use it for scouring, and attempts 

 have been made to use it for the preparation of malic acid. During 

 the manufacturing season this scale should be removed from the pans 

 after each boiling, as it hinders the boiling and requires more fuel to 

 do the boiling. 



Other methods of removing the scale are by scraping, by adding 

 muriatic acid (hydrochloric acid) or vinegar, or by using butter- 

 milk. Scraping weakens the pan and is not to be recommended 

 and acids or vinegars should be used with the greatest care, as the 

 metal of the pan may dissolve along with the scale. 



A fter removing the scale, the pans should be washed out, thor- 

 oughly dried on the inside, and painted on the outside. They should 

 be stored in a dry place, and turned over so as not to collect dirt or 

 water during the summer. If a metal smokestack is used, this should 

 be taken down, freed from soot, painted, and after drying, be stored 

 in a dry place. 



If the arch shows cracking or sagging repairs should be made 

 during the following spring or summer rather than at the beginning 

 of the next season. Care along these lines will preserve utensils, 

 and they will be ready for use on a day's notice in the early spring. 



YIELDS. 



No very definite data can be given on the yields from the maple 

 industry as so many factors enter into the subject. From 5 to 40 

 gallons of sap are obtained from a tree during a season; an average 

 is somewhere between 10 and 20 gallons. Normal sap of an average 

 year contains about 2 per cent of sugar, although it may vary from 

 0.5 per cent to as high as 7 or even 10 per cent. The sugar content 

 varies greatly with the tree, its location, and its past growth. From 

 one tree one can count on from 1 to 7 pounds of sugar per season, 

 or expressed in sirup of standard density, from 1 pint to 1 gallon, 

 though the average from year to year and from tree to tree is about 

 3 pounds of sugar or 3 pints of sirup. Expressing these data in 

 other terms, it is seen that in a normal year 1 barrel of sap (32 

 gallons) should produce a gallon of sirup or 7J pounds of sugar. 

 In many camps and for many years it takes sometimes as high 

 as 50 gallons of sap to make 1 gallon of sirup. First runs of sap 

 are generally richer in sugar, hence take less for a gallon of sirup. 

 From 6J to 9 pounds of sugar, according to the kind, can be made 

 from 1 gallon of standard sirup, with an average of 7 to 8 pounds. 



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