Oil of Mace. 317 



The connexion between temperature and evaporation was next 

 examined. The experiments were classed under five heads, accord- 

 ing to the degree of the thermometer at which they were performed ; 

 those under 40°, those between 40° and 50°, between 50° and 60°, 

 between 60° and 70°, and lastly those above 70°. The four first 

 divisions contained an equal number of observations ; the last was 

 less numerous. The average quantity of evaporation per hour, in 

 the five divisions, was '47 gr., -352 gr., -45 gr., 878- gr., and 1- gr. 

 respectively. The four last numbers indicate, as might be ex- 

 pected, a close connexion" between temperature and the rate of eva- 

 poration; and the apparent anomaly in the first of the numbers may 

 be explained upon the principle, that the greatest degrees of cold 

 are generally accompanied by N. or E. winds, which, in other re- 

 spects, are the most favourable to evaporation. 



The above results appear to be fairly deducible from my experi- 

 ments, and, if not in themselves of any great importance, may, I 

 conceive, be of some value as connected with the researches which 

 have been carried on by yourself and others on the same subject. 

 I am, dear Sir, 



Your's, with much esteem, 



J. BOSTOCK. 



Art, XI. — Experiments on Oil of Mace, communicated by 

 Mr. Wm. BoUaert. 



Genuine oil of mace is a greasy substance of a dark yellow 

 colour; its smell is very aromatic; it is about the consistency of 

 hard butter, and its exterior is occasionally somewhat crystalline. 



When submitted to distillation with water, a highly odorous 

 essential oil arises, and by such repeated distillations, a substance 

 remains which is completely inodorous. The essential oil exists in 

 it, in very small quantities only. The substance which forms the 

 subject of the following experiments, was found in examining the 

 above oil, as well as some other aromatics, with a view to aspertalu 

 the nature of the acid ipattev which most of theri:i coptejin. 



