670 



SCIENCE. 



[N. S. Vol. XVII. No. 434. 



Petroleum from the corniferous limestone 

 in Canada resembles Ohio petroleum in con- 

 taining the series C„H2„+2, up to C,jHj^, but 

 this oil contains larger portions of the heavier 

 series 



C„H2„, C„H2„_2, C„H2„_i, 



which explains its higher specific gravity. 

 In Texas and California petroleum the series 

 C„ H2„+2 does not appear, and the main body 

 of the oil is composed of the series poorer in 

 hydrogen. 



As a result of the above investigations, 

 petroleum can be defined as a mixture of a 

 few series of hydrocarbons, and products from 

 different fields differ only in the proportions 

 of the series contained in them. A great 

 field for chemical research yet remains in 

 ascertaining the structure of the series de- 

 scribed above, and of the so-called asphaltic 

 hydrocarbons, which can not be distilled with- 

 out decomposition. The composition of the 

 oil from different fields should have an im- 

 portant bearing on the question of the forma- 

 tion of petroleum, and there is a field for the 

 chemical geologist to study, more intimately 

 than has yet been done, the occurrence of 

 petroleum in connection with its composition. 

 Arthur M. Oomey, 



Secretary. 



IOWA ACADEMY OF SCIENCES. 



The seventeenth annual meeting of the 

 Iowa Academy of Sciences was held in Des 

 Moines, December 30 and 31, 1902. 



The following papers were presented at the 

 sessions : 



' Living Plants as Geological Factors,' by 

 B. Shimek. This was a discussion of the 

 influence of living plants in checking erosion 

 and thus overcoming in part the destructive 

 action of running water. Their constructive 

 effect was also considered, and examples were 

 given of their influence in the formation of 

 new deposits by serving as an anchorage for 

 materials brought from a distance. Plants 

 are believed to have been important factors 

 in the formation of the loess. There is much 

 evidence that the loess was deposited by the 

 wind upon plant covered land surfaces. 



'The Solar Surface During the Past 

 Twelve Tears,' by David E. Hadden. This 

 paper was a review of a series of sunspot 

 observations made by the writer from 1890 

 to 1902. Daily observations were taken, 

 usually about noon in the autumn and winter 

 and between seven and eight o'clock in the 

 morning during the warmer season. During 

 the period under review about 1,750 groups 

 were observed on the visible disk, the greatest 

 number, 285, being registered in 1893, and the 

 least number, 18, in 1901. 



' The Origin of the Lignites of North Da- 

 kota,' by P. A. Wilder. All the workable 

 lignite beds of North Dakota are regarded as 

 being of Laramie age. The beds of this age 

 consist mainly of clays which are not fissile 

 or shale-like, and the lignite is interstratified 

 with these clays. The lignite is believed to 

 have been formed in fresh-water lakes which 

 originated during the Rocky Mountain uplift 

 and were fed by streams coming from the 

 west. These rapidly flowing streams would 

 carry much timber and deposit it in the lakes, 

 thus giving rise to the vegetable accumula- 

 tions which produced the lignite. 



Other papers presented were the following: 



H. E. SuMMEES : Presidential address, ' Some 

 Problems of Heredity and Evolution.' 



L. H. Pammel : ' Some Ecological Notes on tlie 

 Vegetation of the Uintah Mountains.' 



Pbank L. Almt : ' Some Observations upon the 

 Action of Coherers when Subjected to Direct 

 Electromotive Force.' 



Howard E. Simpson : ' The Accretion of Flood 

 Plains by Means of Sand Bars.' 



B. H. Bailey: 'The Duck Hawk [Falco 

 peregrinus anatum) in Iowa.' 



H. W. NoBEis : ' The Membrane Bones in the 



Skull of a young Amphiuma.' 



A.' N. Cook : ' The Preparation of Phenylether.' 

 A. N. Cook and W. J. Morgan : ' The Sioux 



City Water Supply.' 



C. R. Keyes : ' Significance of the Occurrence 

 of Minute Quantities of Metallic Minerals in 

 Rocks.' 



C. R. Keyes : ' Genesis of Certain Cherts.' 

 J. B. Weems and Alice W. Hess : ' The Chem- 

 ical Composition of Nuts as Food.' 



J. B. Weems and E. C. Myers : ' The Prepara- 

 tion of Ammonia-free Water for Water Analysis.' 



