Notices of the Labours of Continental Chemists. 15 



nature. The protective power of a slight covering of soil or 

 vegetable matter is extraordinary; some potatoes were covered 

 with about two inches of earth and others left exposed on the 

 surface of the ground at the same spot of the garden in No- 

 vember ; a frost occurred at night, the thermometer sinking 

 to 28° Fahr., and it was found that all the uncovered potatoes 

 were frozen, their cellular tissue being broken up ; whereas 

 the buried specimens were entirely free from the action of the 

 cold. The temperatjire of springs is worthy of notice as a 

 proof of the non-conducting nature of the earth, whereby it 

 is well calculated to preserve organic structures from the ef- 

 fects of frost. 



These conjectures are advanced not as satisfactory argu- 

 ments against the apparent objections detailed, but only as 

 throwing out hints for future researches. These objections 

 do not invalidate our measures, for they are demonstrable. 

 The deductions may be in error, but we are content to offer 

 the experiments as a contribution to the science of botany. 



D. P. G. 



II. Notices of the Results of the Labours of Continental Che- 

 mists. By Messrs. W. Francis and H. Croft. 



[Continued from vol. xx. p. 225.] 



On the Oils of Fennel, Anise, and Star-anise (Illicium anisatum). 



]\/T CAHOURS has examined the stearopten of these three 

 -r A • oils, and has found them to be perfectly identical ; the 

 substance used for the experiments was generally made from 

 the oil of anise, because from this oil it can be obtained in 

 larger quantities than from either of the others. The solid 

 oil can be very easily obtained pure by expression and cry- 

 stallization in alcohol. It crystallizes in white shining leaves. 

 Its specific gravity is nearly equal to that of water. It is pul- 

 verisable at 0°, melts at 18° C, and boils at 222°. On being 

 converted into vapour it appears to suffer some change, so 

 that the observed density of the vapour does not agree with 

 that calculated from the formula. In a solid state it is not 

 changed by exposure to the air, but if kept fluid for a length 

 of time it is converted into a resin ; chlorine and bromine act 

 violently on it; alkalies have no action except when employed 

 in the manner proposed by Dumas and Stass, in which case 

 an acid product is obtained. Strong acids, as the sulphuric, 

 phosphoric acids, &c, change it into an isomeric body. The 

 atomic weight of the solid anise oil was determined by mea- 

 suring the quantity of hydrochloric acid absorbed by it The 

 formula is C 20 H 24 O 2 . 



