358 Mr. C. Tomlinson on the Cohesion-Figures of Liquids. 



figure of a similar type is produced on the surface of oJive oil 

 (see PI. V. fig. 6), and will be described further on. 



The benzole figure at 83° consists of a small central disk sur- 

 rounded by an engine-turned pattern, beyond which rippled 

 waves extend to the circumference of a large figure. On the 

 cold oil the engine-turned pattern is wanting (see fig. 11). Pa- 

 raffin oil gives a somewhat similar figure. The turpentine figure 

 consists of a central boss surrounded by a large flat ring. On 

 the cold oil, a drop of oil of cajuput has a central depression sur- 

 rounded by a large flat ring. 



Paraffin. — Solid paraffin was melted in an evaporating-dish, 

 and after the heat had been removed and the surface had become 

 tranquil, a drop of ether, allowed to fall on the surface at 180°, 

 was at first spheroidal ; it then flattened down, and by its evapo- 

 ration solidified a portion of the paraffin with which it was in 

 contact; the solidified portion rushed wildly about under the 

 retroactive force of a little remaining ether, until it disappeared 

 by solution in the liquid paraffin. 



Alcohol formed a disk which sailed about, shooting out flat 

 disks resembling petals, so as to give the figure the appearance 

 of a flower (see PL V. fig. 5). 



Paraffin oil formed a disk which sailed about with much agi- 

 tation, sending off waving lines. The oils of turpentine and 

 cajuput, and some others, solidified a portion of the paraffin — in 

 some cases permanently, while in others the solidified portions 

 moved about over the surface. 



Olive oil and pure tallow oil assumed the spheroidal state on 

 the surface at 180°, and then sank. 



Spermaceti. — On the surface of melted spermaceti a drop of 

 ether becomes spheroidal, or, if the temperature be not too high, 

 flattens down into a small raised disk which spins rapidly ; or it 

 may solidify a portion of the spermaceti, when the solid portion 

 darts about in wide sweeps rapidly over the surface until it is 

 again taken up by the liquid. 



Alcohol, when the surface is at about 160°, forms a well-defined 

 disk with a waving border and concentric rings, and a delicately 

 fringed iridescent edge (see fig. 2) ; but at a lower temperature 

 (about 116°) it solidifies a portion of the spermaceti into the 

 form of a small coracle, which sails about carrying its small cargo 

 of alcohol. Turpentine at 121° behaves in a similar manner, 

 only the solidified portion breaks up and darts about. Oil of 

 cajuput at 127° forms a large disk with a faint depressed centre. 

 Benzole forms a large plain disk, in the centre of which is a 

 small spinning disk with a raised conical projection in the centre. 

 Camphorated spirit slightly chills the spermaceti, rotates in the 

 form of a small lens or boss with an agitated kind of motion ; 



