366 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



If it is intended for sug'ar take out a spoonful and pour it on snow or ice; 

 if it becomes hard and brittle it will make good sugar; or pour a small 

 quantity into a dish, and if in the right state for sugar it will continue to 

 boil for some minutes after being removed from the kettle. It should be 

 stirred very slowly when in the trays. 



Prof. S. D. Tillman. — The amount of maple sugar made in the United 

 States in the year 1860 was, in round numbers, 39,000,000 pounds. The 

 high price of sugar doubtless stimulated farmers to tap, during tlie present 

 Spring, more than the usual number of rock and red maples, and as the 

 flow of sap is reported to have been very great, it may be safely concluded 

 that the maple sugar crop of 1864 will far exceed that of any former year. 

 Each farmer who produces sugar is also a manufacturer, for the sap is 

 boiled down, granulated and oast into cakes, ready for the market, either 

 in his own domicile or in the " sugar camp," generally located near the 

 center of his maple grove. 



HOW TO INCREASE THE FLOW OF SAP. 



At my suggestion, the correspondent, Mr. Blinn, tested the strength of 

 the sap drawn at various heights of the tree, the highest being taken at 

 fifteen feet, and the result proved that the sap increases in sweetness, 

 slightly, with increase of height. The sweetest sap tested was 3° by the 

 Baumd h^'drometer. The position of the tree was found to affect the 

 strength of the sap; in trees near water-courses the saccharine quality was 

 extremely diluted. Sap from the root of a tree stood at |° Baume. The 

 first flow of sap being the best, it occurred to me that it might be increased 

 by being allowed to pass into vacuum. I requested that a small India-rub- 

 ber bag, from which the air had been driven, should be attached to a spile, 

 or a vessel from which the air had been exhausted by means of an air-pump. 

 The still more simple plan was proposed of placing a little water in a tin 

 can and after heating it until the steam had driven out the air, closing it 

 and attaching it by an air-tight connection with the spile. The first and 

 last plans were tried, and with complete success. 'H'^ith the steam can, in 

 which the steam was condensed when the can was withdrawn from the 

 flame, the quantity caught in twelve minutes was four fluid ounces; the 

 quantity which ran from the same spile in the usual way in the same time 

 ■was 1| ounces, the increase of flow being about 114 per cent. Subsequent 

 trials gave always over 100 per cent increase. The community at Canter- 

 bury have made some syrup from the sap of several varieties of the birch; 

 also from that of the oil-nut or butternut tree, but they have not succeeded 

 in granulating it. 



The flow of sap in the maple is influenced bj'- the weather to a great 

 degree. The most abundant flow is just after there has been a white frost 

 at night. A humid state of the atmosphere is considered preferable to a 

 clear and cloudless day. At Canterbury a north-west wind is considered 

 the most propitious; a southeast next best; east, medium. The winds from 

 all other points of the compass are less favorable, while a breeze from the 

 south destroys all hope. An occasional rain during the sugar season is 

 beneficial, if the fall of water is very abundant, the flow of sap is greatly 

 increased immediately after, but its sweetness is much diminished. 



