TEREBINTHINA CANADENSIS. G13 



consistence, and of a light straw-colour with a greenish tint. By keeping, 

 it slowly becomes thicker and of a somewhat darker hue, but always 

 retains its transparency. When carefully examined in direct sunh'ght, 

 it exhibits a slight greenish fluorescence in the same degree as pthcr 

 turpentines or as copaiba ; this optical power appears to increase if the 



balsam is exposed to a heat of about 200° 0. 



Canada balsam has a pleasant aromatic odour and bitterish, feebly 

 acrid, not disac^reeable taste. Ofi account of its flavour it is sometmito 

 called Balm of Oilead, but erroneously, as this latter is derived frr)ni a 

 tree of the genus Balsamodendron growing in Arabia.^ ^ Wc found a 

 good commercial balsam to have a sp. gr. of COOS at 14'5° C, water at 

 the same temperature being 1-000. Four parts, mixed with one ot 

 benzol and examined in a column of 50 mm. in length, deviated a ray 

 of polarized light 2° to the right. The balsam is perfectly soluble in any 

 l)roportioTi in chloroform, benzol, ether, or warm amylic alcohol; and 

 the solution in each case reddens litmus. With sulphate of carbon it 

 mixes readily, but the mixture is somewhat turbid. Glacial acetic '.ma, 

 acetone or absolute alcohol dissolve the balsam partially, leaving a ter 

 ebullition and cooling, a considerable amount of amorphous residue. 

 Colophony and Venice turpentine are completely dissolved by^ tne 

 liquids in question, as well as by spirit of wine containing 70 to / ^ per 

 cent, of alcohol. 



Chemical Composition-Like all analogous exudations of the 

 Coniferce, Canada turpentine is a mixture of resins wi h an ^f^^^l^^ 

 If thi latter is allowed to evaporate, the former are left as a tran^p^r^^^ 

 somewhat tough and elastic mass. The proportion of ^h^ ';'^™P^^^^^^^^ 

 is within certain limits, variable in different samp es J^^^ J^^^^j 

 beforementioned lost after an exposure in a ^team-bath duiing seve^a 

 days, no less than 20 per cent of -^ti ^ .^^^^^^^^ 

 experiment was made on a very small scvie, as witu - » 



" %^^ion with water, it is not easy to o^J^^^^^, 

 18 per cent, of essential oil The resin in this ^f f ;^ JJ^^^^?;'" V^^ater; 

 non-transparent mass, retaining obstinately a Jai e i i^ tempera- 



which can only be removed by keeping it for some time 1 



ture of 100°-17G° C. . .,, ^.^^ • colourless, and has 



The oil as obtained by distillation with ^^f ,^;^^^ ,?7,^'iee^ble smell 

 the odour of common oil of t;^n^entme ^rather than^^t^^ ^g i„,igBificant 

 ot the balsam; it consists ot an oil, u xi , - ^.^^^ 1^^ provtid 



proportion of an oxygenated oil, the P^"^^^°.'f^^'|'„,etnllic sodium, after 

 by the slight evolution of hydrogen on add^tmn ot n ^^^^^^^.^^ ^^ ^^^_ 

 the oil has been freed from water by cont«cUutn lus ^ ^^.^^.^ ^^ ^^^^ 

 cium. After this treatment, a small propoition « _^^^ .^^ ^^j^ 

 1G0°, but by far the larger part boils at l^^^ J^?. ^ ^^^^ examined 

 distilling at last at 170° andiibove. _ The ^^ obtained a^t^ ^^^^-^^ ^^^^ ^^^^ 



under the conditions already mentioned ^i^^/^Yhe left. The portion 



power of rotating a ray of po^^i'if ^,fS^^^,i,..t . but that passing over 

 distilling at 1G0° docs not differ ^ this respect bu ^i ^.^^^,^^ ^ 



at 170°, deviates the ray 72° to the Icft^ ^'^^^ ^^.^-^^^ of each mixes 

 large proportion of glacial acetic ^cid; »" 1 fcs on cooling, 



perfectly at about sl" C, but some acetic acd sepai 



