swingle: botanical name of the lime 463 



find its way into the lava it must do so as a gas and on the same 

 terms as the other atmospheric gases, for the reason that the 

 critical temperature of water is but 374°, whereas the lava tem- 

 perature is 1000° or higher. It is therefore plain that capillary 

 phenomena (Daubree) can not be invoked to assist in the trans- 

 mission of water into the liquid lava in the temperature region 

 between 374° and 1000° in which H2O has no surface tension. 

 But quite apart from this, there is no more reason for assuming 

 that the water is of atmospheric origin than for assuming the 

 carbon compounds to be so. 



In conclusion, we may add that the much discussed question 

 whether water is an active participant in volcanic activity ap- 

 pears to find adequate answer in these preliminary experiments, 

 so far as Kilauea is concerned. Not only was water actually 

 collected in considerable quantity (300 cc.) directly from the 

 liquid lava, at a temperature of 1000° or higher, but this was 

 done under conditions which completely excluded contamination 

 with air. Moreover, the presence of free hj^drogen associated 

 with CO2 and SO2 at this temperature is of itself a sufficient 

 guarantee of the presence of some water among the volcanic 

 gases. Indeed, the reaction between Ho and CO2 (the water 

 gas reaction H2 + CO2 ^ CO + H2O) has long been well 

 known and has been studied in great detail. ^ 



BOTANY. — The botanical name of the lime, Citrus aurantifolia- 

 Walter T. Swingle, Bureau of Plant Industry. 



The lime, altho closely related to the lemon and the citron, 

 differs from them in having small white flowers, fewer stamens, 

 thin-skinned fruits and winged petioles articulated with the blade 

 of the leaf. Because of these and other divergent characters it 

 seems proper to recognize it as a distinct species, as has been 

 done by many botanists. It is quite distinct from Citrus his- 

 trix, D. C, which is considered by Bonavia^ to be the ancestral 



^ F. Haber, Thermodynamik technischer Gasreactionen. Berlin, 1905. 



^ Bonavia, E., 1886, On the probable wild source of the whole group of culti- 

 vated true limes {Citrus acida Roxb., C. medica, var. acida of Brandis, Hooker, 

 and Alph. de CandoUe), in Journal Linn. Soc, Botany, 22: 213-218, figs. 1-3, (n. 

 145, Jul. 23). 



