270 



SCIENCE, 



[N. S. Vol. XXIV. No. 609. 



color it would suggest a 'bud shoot' of a 

 Cassandra from an Andromeda. The ap- 

 pearance of two generic types in the 

 branches of one shoot is very striking. 



On Monday, July 2, a party of thirty- 

 four drove to Enfield Gorge, alighting at 

 the foot of the gorge, while the carriages 

 were taken to the head of the gorge, a little 

 more than two miles distant. The numer- 

 ous successive falls and cascades were ob- 

 served, also the geological formations, but 

 especially the vegetatioa. There were nu- 

 merous liverworts in the wet rock walls. 

 In one place Preissia and ConocepJialus are 

 abundant and are usually brought into 

 zonal formation by the different moisture 

 conditions which vary according to the sur- 

 face contour of the perpendicular rock 

 wall. At a short distance Pellia usually 

 grows where there is a greater quantity of 

 water dripping down the rock. This year 

 there is more moisture than usual. The 

 dripping water is so abundant that it is 

 killing out the Preissia and ConocepJialus 

 in certain spots and the Pellia is coming in 

 and overgrowing them. These features 

 were very easily demonstrated. Higher up 

 on the clay bank at this place Blasia is 

 abundant, and on the flat rocks below Mar- 

 chantia was found. 



Near the upper end of the gorge was an 

 abundance of the fern, Pellcea gracilis, on 

 the moist rocks. The vegetation of the 

 small alluvial plains here and there was 

 rich in forest and shade plants which af- 

 forded an excellent opportunity for obser- 

 vation of 'mosaics' and various ecological 

 features. 



The interest shown in a meeting in which 

 the out-of-door features occupied so promi- 

 nent a place suggests the desirability of 

 their annual repetition, although it is by 

 no means to be taken for granted that field 

 excursions might always be organized under 



such favorable circumstances as those of- 

 fered by Ithaca and the Cornell botanists. 

 D. T. MacDougal, 

 Chadrman Section G. 



SCIENTIFIC BOOKS. 



Der Bau des Fixsternsy stems mit h&sonderer 

 BeruecJcsichtigung der photometrischen Be- 

 sultate. Von Dr. Hermann Kobold. Fried- 

 rich Vieweg lond Sohn. 1906. M. 6.50. 

 This volume is No. 11 of a series, ' Die 

 Wissenschaft,' whose declared purpose is to 

 place before the public, from time to time, a 

 digest of the progress that has been made in 

 definite departments of scientific research. 

 Designed alike for the instruction of the gen- 

 eral reader and for the orientation of the pro- 

 fessional student in his own field, Dr. Kobold's 

 work must be regarded as upon the whole an 

 eminently satisfactory achievement. It is, 

 indeed, probable that competent critics will 

 dissent vigorously from some of his conclu- 

 sions and will regard as far from final his 

 judgment upon much of the conflicting evi- 

 dence marshaled in the test. But with all 

 due reserve in these respects the book possesses 

 great merit both as a compilation of data rela- 

 tive to the structure of the stellar system and 

 as a summary of current theorizing upon that 

 data. 



In some twoscore pages there is passed in 

 brief review the methods of determining such 

 fundamental data as the position, brightness 

 and color of individual stars, stellar spectra, 

 parallaxes, proper motions and the apparent 

 distribution of stars upon the sky. Then 

 follows the backbone of the work, a hundred 

 pages devoted to a critical consideration of 

 the present state of knowledge along these 

 several lines, with particular stress upon prob- 

 lems of stellar motion. The author here de- 

 fends the thesis, supposed to be original with 

 him, although recently brought into promi- 

 nence by Kapteyn, that the stellar motions 

 can no longer be regarded as lawless in their 

 arrangement, directed in equal measure to- 

 ward all parts of the celestial compass. Rather 

 must we consider them as having a definite 

 relation to the Milky Way, the exact nature 



