Mat 28, 1909] 



SCIENCE 



869 



tention. The spectrum of the Hercules 

 cluster ]Sr. G. 0. 6205, obtained by Dr. Eath 

 is quite remarkable. He says: 



It is composed of a number of parallel strips of 

 different intensities, containing a few faint ab- 

 sorption lines. Eacli strip is probably the spec- 

 trum of a single star, or group of stars. No two 

 strips contain the same set of lines. Four of the 

 strips were strong enough to be measured. 



In the following table the first column 

 states the number of the strip, the second the 

 wave-length, the third the intensity, the 

 fourth the corresponding wave-length of 

 radium emanation, the fifth its intensity. 



TABLE in 



strip. 



(2) 



It! 



4) 

 (3) 

 (4) 

 (2) 



3935 

 3966 

 3970 

 4118 

 4294 

 4302 

 4340 

 4463 

 4790 



3933.3 



3971.9 



4114.9 



4308.4 



4340.8 

 4460.0 

 4796.7 



7 



2 



50 Ea. 

 10 

 1 



It will be noticed that to the single line of 

 strip (3), I have assigned the radium line of 

 high intensity, although an emanation line 

 A 4340.9, intensity Y, also exists. I think the 

 evidence for the existence of radium emana- 

 tion in this cluster is sufficient to make dis- 

 cussion unnecessary. It will be seen that for 

 the diilerent strips the lines vary. Difference 

 of excitation, due to the difference of physical 

 state of each star, completely accounts for the 

 variation. In the globular clusters N. G. C 

 7078 and 7089, the hydrogen lines are, as Dr. 

 Fath indicates, probably evident from H/3 to 

 H^. Radium emanation must, however, also 

 claim A 4102.2, A 3971.9 and A 3933.3 in each 

 of these star clusters. 



It may not be amiss to venture a few sug- 

 gestions : 



1. Each photograph or observed spectrum 

 of a nebula, star cluster, or bright line star, 

 should be treated as a separate entity in pub- 

 lication; otherwise the successive changes in 

 given lines are averaged out of existence. 



2. If possible, the spectrum of the nebula of 



Andromeda should be repeatedly photo- 

 graphed. 



3. It should be the aim to photograph as 

 soon and as effectually as possible the spectra 

 of the short-period variables in globular star 

 clusters even if at first integrated results, both 

 as to stars and as to periods, are obtained. 



In conclusion, I must state that I am quite 

 conscious of the incompleteness of this dis- 

 cussion. Indeed, it is the manifest complex- 

 ity of the subject that has made me, hitherto, 

 recoil from a preliminary application of the 

 theory for publication. Eadiimi has been 

 known for at least ten years as a terrestrial 

 element, its spectrum has been repeatedly de- 

 termined and compared with the spectra of 

 the heavenly bodies, and yet up to the present 

 moment there has been published, so far as I 

 know, no demonstrative evidence concerning 

 its existence in the heavens. On the con- 

 trary, careful comparisons made by chemists, 

 physicists and astronomers, have apparently 

 shown that the spectra of radium and radium 

 emanation, the element into which radium is 

 at once transformed, are not identifiable with 

 stellar spectra. It is, therefore, significant 

 that the identifications here made were sug- 

 gested by the theory of radioaction. 



Monroe B. Snyder 



Philadelphia Obseevatoet, 

 May 3, 1909 



OBSERVATIONS ON THE SHIFTING OP THE CHANNEL 

 OP THE MISSOURI RIVER SINCE 1883^ 



The radical changes which annually take 

 place in regard to the position of the Missouri 

 Eiver channel and the great loss of property 

 occasioned by the same have presented a prob- 

 lem worthy our careful consideration. In ad- 

 dition to the scores of farms which are washed 

 out annually the railroads suffer greatly by 

 having their roadbeds destroyed. Hence, 

 this becomes an economic problem of vast 

 proportions. 



In the following chart we have represented 

 a portion of the river valley near the village 

 of Peru, including ten or twelve miles of the 

 river bed. The upper dotted line represents 



'Read before the Nebraska Academy of Sci- 

 ences. 



