654 



SCIENCE 



[N. S. Vol. XXX. No. 775 



plants than I had expected. The leaves of 

 grape were fairly cleaned, but the fruit was 

 not, and the effect on the leaves of plum, prune 

 and oak was slight: the dust was on them in 

 quantity. This rain, furthermore, came un- 

 usually early. 



The climatic conditions here being so dif- 

 ferent from those elsewhere, I feel compelled 

 to expect the results which I have indicated, 

 unless the operation of the cement manufac- 

 tory is so modified as to check the discharge of 

 dust in quantity. 



George J. Peirce 



Stanford University, Cal., 

 October 1, 1909 



THE ALG^ OF THE ITHACA MARSHES 



Investigations on the fauna and flora of 

 the marshes of the upper Cayuga Lake Basin 

 during the past summer were continued at the 

 Biological Field Station of Cornell University. 

 Various studies were in progress. The writer 

 undertook the study of the algse. His investi- 

 gations were made in connection with the 

 work of Dr. J. G. IsTeedham, and were directed 

 toward the solution of the problem of the algal 

 food supply of herbivorous aquatic animals 

 that are used as food by fishes. No local data 

 being available, a preliminary study of the 

 algse of the marshes was undertaken. With 

 little variety of conditions, a great number of 

 species was not to be expected ; however, nearly 

 all the genera of the commoner fresh-water 

 algse were represented, and perhaps a more 

 thorough search would supply the missing 

 ones. Over seventy genera were found, but 

 the species were not all carefully worked out, 

 owing to the unsatisfactory state of their lit- 

 erature. Material for future work on them 

 has been preserved and will be worked over 

 later. 



The genus Chcetophora is especially abun- 

 dant in this region, and is represented by four 

 species, three of which, 0. elegans, 0. incras- 

 sata and C pisiformis, are very common. The 

 dominance of this genus, and the fact that it 

 is used extensively as food by aquatic animals 

 that have importance as food for fishes, lead 

 us to expect that it will be of some economic 



value and a special study of its habitat and 

 capabilities of increase will be made in the 

 future. The study of the optimum conditions 

 for the development of several species of 

 Bpirogyra, Mougeotia and Chcetophora was 

 undertaken in order to facilitate the cultiva- 

 tion of these algse, should they prove of eco- 

 nomic importance. The results from these 

 experiments, and from observations carried on 

 in nature, lead us to believe that such forma 

 might with proper facilities be raised on a 

 large scale with good results; perhaps in such 

 quantities as Dr. Needham's previous studies 

 of artificially reared may-flies indicate may 

 be demanded. 



A beginning was also made in the study o£ 

 the periodicity of the marsh algse. It is hoped 

 that facilities may be provided in the future 

 for carrying on observations continuously for 

 several years, as this seems to be the only way 

 in which exact information concerning the 

 ecology of the algse can be obtained. 



An interesting Phycomycete, parasitic on 

 Yolvox gloiaior, was discovered during Au- 

 gust, and this fungus will be described after 

 further work has been done on its life history. 

 H. A. Anderson 



THE MOLECULAR CONSTITUTION OF SOLIDS* 



According to the author, it is supposed and 

 generally so stated, owing to complex move- 

 ments and forces supposed to be present in 

 solid bodies, there must be special difficulties 

 to which it is due that the molecular thermo- 

 dynamics and kinetics of solids can not be 

 fully accounted for on the same basis as those 

 of the gaseous bodies. 



The present paper is calculated to show 

 that the supposed difficulties are largely imag- 

 inary and that there are a notable number of 

 solid and liquid substances, for which, accord- 

 ing to the calculations and tables presented 

 by the author, no essential difference exists 

 regarding the mode and kinetic energy of the 

 motion of their molecules as compared with 

 those of gaseous bodies. 



'■Abstract of paper presented at the regular 

 meeting of the Chicago Academy of Sciences, July 

 27, 1909. 



