64: ANNUAL OF SCIENTIFIC DLSCOVEHY. 



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

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

 at 15 feet, and the result proved that the sap increases in sweetness, 

 slightly, with increase of hig'at. The sweetest sap tested was o 3 by 

 the Baum3 hydrometer. The position of the tree was found to affect 

 the strength of the sap ; in trees near watercourses the saccharine 

 quality was extremely diluted. Sap from the root of a tree stood at 

 D Bauml 1 . The first ilow 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-rubber bag, from which the air had been 

 driven, should be attached to a spile, or a vessel from which the air 

 had be>.-;i 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 attach- 

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

 plans were tried, and with complete success. With 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 which the steam was condensed when the can was withdrawn from the 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 

 samj time was 1 1 ounces, the increase of ilow being about 114 per 

 cent. Subsequent trials gave always over 10') per cent increase. The 

 Community at Canterbury have made some sirup 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 the sap in the maple is influenced by 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 northwest 

 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 occa- 

 sional 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. 



CARBONIZATION OF ILLU3IINATING GAS. 



The London Artisiu say>: "The advantiges resulting to gas con-. 

 su'Tiei's tVo:n ths carburizatioti of the g.u supplied by the companies has 

 now become generally recognized, an 1 the apparatus for effecting the 

 thorough mixture of the benzole or naphtha vapor with the gas has now 

 be !! so simplified, that whitever objection* nuy formerly have existed 

 have been entirely removed, so that it may be hoped that Dr. Knapp'.s 

 observation, as to the discovery being of benefit to indtvicluils only, will 

 no longer apply. Referring to n iphthalized gas (as it rniy here be men- 

 tioned tint tin; cirburization is ahvavs effected with mineral naphtha, ben- 

 zole, or some other material not widely different from them), Dr. Knapp, 

 in his well-known Technology, observed that ' the illuminating power 

 of gas is very much increased by the presence of volatile hydrocarbons, 

 and many years ago Mr. Lowe introduced, or rather proposed, a plan for 

 saturating interior qualities, or ordinary coal gas, with naphtha, or the 

 spirit distilled from coal-tar, and thus augmenting its illuminating power 

 nearly one-half. The remarkable increase of light, however, produced 



