HYACINTH. 97 
According to Tilden, one volume of nitric acid, sp. gr. 1:4, is 
mixed with one volume of strong alcohol * and two and a half 
vols. of pure rectified oil of turpentine (French or American), is 
allowed to stand for two days until the smell of turpentine has 
disappeared, and then poured into flat dishes, small quantities of 
alcohol being gradually added to it at intervals of two days. 
About one third of the oil of turpentine is thus converted into the 
terpine hydrate, and a still larger yield may be obtained by con- 
tinuing the operation. 
Terpine hydrate crystallizes in large, transparent, monosym- 
metric prisms which dissolve in 200 parts of cold and 22 parts of 
boiling water, and are still more readily solub!e in alcohol. 
Wiggers, by the action of hydriodic acid on terpine hydrate 
(Dipentenylene glycol) obtained the compound 2C,)H,,+H,O, 
which was investigated by List and named ferpinol +. It is also 
formed when terpine hydrate is boiled or distilled with very dilute 
hydrochloric or sulphuric acid, potassium sulphate, &c., also when 
hydrochlorate of terebenthene is boiled with water, alcohol, or 
alcoholic potash. It is a colourless, strongly refractive oil, which 
boils at 168°, slightly soluble in water, and optically inactive; its 
sp. gr. is 0°852. It has a pleasant odour of hyacinths, especially 
when diluted. By boiling, it suffers partial decomposition, in 
such a manner that the first part of the distillate contains less 
oxygen than the latter portion. 
Tilden found that the above reaction yields a mixture of a ter- 
pene with a compound C,)H,,O, for which he retained the name 
terpinol t. It is shown, by the researches of Professor Wallach §, 
that terpinol is not a simple body, but a mixture in variable pro- 
portions of Terpinol, Terpinene, Terpinolene, and Dipentene ; or, 
rather, that when terpine hydrate is boiled with dilute sulphuric 
acid, or phosphoric acid, the product varies according to the con- 
ditions of the experiment, but the principal constituent is Terpineol, 
which is an alcohol (Dipentenyl alcohol) of the composition 
C,)H,,OH, this name being substituted for “ terpinol” in order to 
* Tt is stated in Jahresb. Chem. 1878, p. 638, that Tilden used methy] alcohol, 
while he actually employed “ methylated spirit.” 
t+ Ann. Chem. Pharm. Ixvii. p. 367, 
t Journ. Chem. Soc. xxxiii. p. 247; xxxv. p. 287. 
§ Annalen der Chimie, ccxxx. p. 251. 
