154 
DR. JOHN STENHOUSE ON VEGETABLE PRODUCTS FROM INDIA. 
State by neutralizing the solutions of the aeicl with the carbonates of those bases. 
Their analysis, however, gave irregular results, as, owing to the smallness of their 
quantity, I could not prepare them in a state of perfect purity. In the former notice 
of the stearopten, already mentioned, it was stated that by long-continued digestion 
with concentrated nitric acid, the stearopten was dissolved, and a colourless crystal- 
line acid produced. This acid is neither oxalic acid, nor, apparently, any of the 
nitrogenated acids. At least when warmed with hypochlorite of lime it gives off no 
chloropicrine. I suspect, therefore, that it will be found to be a new acid, the 
examination of which I hope ere long to lay before the Society. From the physical 
properties and the elementary composition of the stearopten of the Ptychotis Ajowan, 
it struck nie that it was very similar to, if not identical with, the solid portion of oil 
of thyme, described by Lallemand in his recent papers on that substance* * * § . This 
idea induced me to distil the stearopten dissolved in oil of vitriol with an excess of 
peroxide of manganese. As anticipated, besides formic acid, there came over yellow 
drops which solidified on cooling, forming large crystals, having a peculiar odour 
somewhat resembling iodine or kinone, and agreeing in every respect with the sub- 
stance described by Lallemand as thymol. 
Before Lallemand has published his experiments in detail, which are now only 
known from the two notes in the ‘Comptes Rendus,’ I do not think it possible to 
decide with perfect certainty whether thymol and the stearopten of the Ptychotis 
are really identical substances, and even then, perhaps, it will be found necessary to 
make more complete experiments with the stearopten of the Ptychotis. The hypo- 
thesis of their identity, however, appears to me highly probable from the great simi- 
larity existing in the most important properties of those substances. I may add, that 
I agree with Gerhardt'I' in considering the crytallizable substance obtained by 
Arppe:}: from the essential oil of the Horse-mint {Monarda pimctata, huile de monarde), 
to be identical with Lallemand’s thymol and Doveri’s§ less volatile portion of the 
oil of thyme. 
All these substances gave nearly the same numerical results w^hen subjected to 
analysis. 
Doveri observed two boiling-points, one between 175° and 180° C., and the other 
between 230° and 235° C. 
Lallemand found the boiling-point of his thymene to be 105°C., and obtained a 
liquid hydrochloric acid compound. 
Arppe’s crystallizable substance from the horse-mint oil, was found to melt at 
48° C., to solidify at 38° C., and to boil at 224° C. 
'riie crystals were rhombohedral, having one angle of 97° 30' and another of 82° 30'. 
* Compt. Rend, de I’Acad. xxxvii. 498, and xxxviii. 1022. 
t Traitd de Chimie Organique, iii. 610. 
I Annalen der Chemie und Pharmacie, Iviii. 41 ; Chem. Gaz. December 1846. 
§ Annales de Chimie et de Physique, [3] xx. 174. 
