CHEMICAL SCIENCE. 201 



a larger amount of hydrogen. This latter element exercises, in this 

 case, a very essential importance in their heating powers, and must not 

 be neglected in comparing the analytical with the economic results. 

 As a general rule, subject to marked exceptions, the practical value of 

 a coal rises with the increase of these two combustible elements. Nev- 

 ertheless, the mechanical conditions of a coal very frequently modify the 

 practical result to an extent which was scarcely to be expected. The 

 physical condition of a coal, according as it facilitates or opposes the 

 entrance of air for combustion, produces a most marked influence in its 

 evaporative powers, and often determines the practical results obtained 

 from it, more than the composition of the coal itself. It is, therefore, 

 not a safe guide to rely wholly on the analysis, unless, at the same 

 time, practical experiments are found to coincide with the approxima- 

 tive value indicated by analysis. London Patent Journal. 



OX THE USE OF RECTIFIED COAL-OIL. 



A COMMUNICATION was recently presented to the French Academy, 

 by M. Edward Robin, "upon the advantages of rectified aromatized 

 coal-oil, (huile de houille,) employed for the preservation of animal and 

 vegetable substances." He says : 



"I have the honor of submitting to the examination of the Academy 

 a portion of flesh which, notwithstanding the presence of damp air, has 

 been preserved by the vapor which coal-oil emits at ordinary tempera- 

 tures. This mode of preservation, extremely cheap, keeps flesh, for an 

 indefinite time, in all its freshness. In an economical point of view, 

 as well as in the satisfactory character of its results, coal-oil has evi- 

 dently many advantages over the liquors hitherto employed in our 

 museums. The specimens which in the museums are kept immersed 

 in these liquors are, it is true, preserved from putrefaction ; but they 

 undergo change they are no longer fresh animal substances ; whereas 

 entire birds, with their feathers, foetus of every age, placed in well- 

 stopped bottles, at the bottom of which has been placed a little coal-oil, 

 have experienced no change whatever. The conservative property of 

 coal-oil is applicable, as I have said, to vegetable as well as animal sub- 

 stances. The botanist can use it for the preservation of fruits and 

 flowers. Experiments now in process of execution seem to indicate 

 that certain flowers may be thus preserved with the appearance of life, 

 and without any very notable change of color. In all external appli- 

 cations, where the object is to ease pain and remove inflammation, this 

 substance may be used as a substitute for the essential oils of plants, 

 for ether, for camphorated alcohol, and even for chloroform and other 

 costly substances which possess no known virtue rendering them su- 

 perior to rectified and aromatized coal-oil." 



PRESERVATIVE INFLUENCE OF CHLOROFORM. 



M. ACGENDRE, in a paper before the French Academy, on the pre- 

 servative and disinfecting influence of chloroform,* supposes that its 



*See Annual of Scientific Discovery, for 1851, p. 217. 



