190 Mr. C. Tomlinson on the Cohesion-Figures of Liquids, 



another; but there is no mistaking the cohesion-figure of any 

 oil of lavender that I have tried for that of another oil, unless 

 that other oil be made to resemble oil of lavender by artificial 

 means. For example, oil of coriander (sp. gr. "859 to *871) 

 lias a cohesion-figure peculiar to itself; but if it be made to 

 combine with a small portion of camphor under a gentle heat, 

 so as to bring it to about the same density and texture as oil of 

 lavender, it will display the lavender figure ; with a certain other 

 proportion of camphor the figure becomes again different : a film 

 is formed which breaks up rapidly into flat disks; each disk 

 becomes fringed with a silvery ring, which undergoes constant 

 motion and change; the most lovely iridescent colours then 

 take the place of the silver tint ; the fringe becomes more copious, 

 and the colours more lustrous, until the whole vanishes. With 

 yet another proportion of camphor in coriander oil another set 

 of effects is induced. The film splits into large disks ; the edge 

 of each disk is the thinnest part ; and as ccrhesion reasserts 

 itself (as shown by the shrinking of each disk), the edge, by its 

 adhesion to the water, is left behind, it being cut off by a visible 

 action, just as if a sharp instrument were being slowly passed 

 round it. The piece thus cut off forms satellites to the parent 

 disk; and as the latter continues to contract, there may thus be 

 two or three concentric circles of satellites of different magni- 

 tudes; but they in their turn disappear by evaporation and 

 solution, somewhat after the manner of the principal disk. 



I have also produced the lavender pattern by the addition of 

 camphor to ol. pimentse and ol. citronellse. A drop of the 

 former produces a very eccentric film : the Carrigeen-moss or 

 lavender pattern plays about in flattened disks ; and the disk 

 suddenly recovering its form, the pattern is produced from the 

 other side of the same disk. The camphorated citronella dis- 

 plays the lavender pattern on a large scale. 



Again, camphor in solution in oil of bitter almonds entirely 

 changes the figure of that oil. The film quickly breaks up into 

 disks, each of which throws out waving cilia; and these set the 

 disks sailing about, while they rapidly disappear by solution and 

 evaporation. 



The action of cold upon the essential oils is not very apparent, 

 either as respects the oils themselves or their cohesion-figures. 

 I reduced a number of such oils to 0° F. Oil of peppermint 

 became cloudy ; ol. cassias cloudy and thick ; anthemis slightly 

 cloudy ; cinnamon less fluid ; patchouli viscid ; but this low 

 temperature did not appear to have any effect on the oils of 

 juniper, menthis, cloves, citronella, anethum, myristica, lavender, 

 coriander, rosemary, verbena, origanum, bitter almonds, and 

 sassafras. Glycerine became a little more viscid, and benzole 



