948 



SCIENCE 



[N. S. Vol. XLI. No. 1069> 



study of absorption spectra in the ultra-violet. 

 It was not found advisable to use capillary 

 tubes, nor to work at such low pressures as 

 Friederichs did. The best results were ob- 

 tained with end-on tubes, from 5 to 10 mm. in 

 diameter and about 30 cm. long, with quartz 

 windows, and at pressures in the neighborhood 

 of 5 mm. The necessary exposure varies from 

 5 minutes to an hour, according to the width 

 of the slit, the absorptive power of the medium, 

 etc. I have obtained a beautiful photograph of 

 the absorption spectrum of benzol vapor with 

 fifteen minutes' exposure. 



E. P. Lewis 

 ITniveesity of California, 

 May 18, 1915 



THE IOWA ACADEMY OF SCIENCE 



The twenty-nintli annual session of the Iowa 

 Academy of Science was held in the Hall of Phys- 

 ics, State University of Iowa, Iowa City, on April 

 30 and May 1, 1915. Over one hundred members 

 ■were registered. At the opening session on Fri- 

 day afternoon, after the transaction of preliminary 

 business, the president, Professor H. S. Conard, 

 called for the presentation of papers of general 

 interest. At 4 p.m. the academy separated into 

 sections for the further reading of papers as fol- 

 lows: section one, botany; section two, physics, 

 chemistry and mathematics; section three, zoology, 

 geology, psychology, medicine. 



Professor EUery W. Davis, of the department of 

 mathematics in the University of Nebraska, gave 

 the annual address on the subject "Uncertainties," 

 a discussion of the foundations of exact knowl- 

 edge. 



On Saturday morning the sections resumed their 

 meetings, except that the Iowa section of the 

 American Chemical Society met independently. 

 At the business meeting the following officers were 

 elected for the coming year. 



President: Harry M. Kelly, Mount Vernon. 



First Vice-president : G. W. Stewart, Iowa City. 



Second Vice-president: Charles K. Keyes, Des 

 Moines. 



Secretary: James H. Lees, Des Moines. 



Treasurer: A. O. Thomas, Iowa City. 



The sectional meetings were so successful that a 

 continuation of the plan was decided upon for the 

 next annual meeting. 



Luncheons were enjoyed on Friday evening by 

 the geologists and geographers as guests of Dr. 



and Mrs. Kay, by the mathematicians and by the 

 physicists. A general luncheon was participated 

 in by the members of the academy on Saturday 

 noon, following the business session. 



Program 

 (Abstracts are by the authors.) 

 Preliminary Notes on Nectar Production: L. A. 

 Kenoyeb. 



An Anomalous Sichory-nut ; An Exoiasidium on 



Armillairia; The Mole of Soil Fungi: Gut West 



Wilson. 

 The Forest and ShriCb Flora of Western Iowa: L. 



H. Pammel, G. B. MacDonald and H. B. Clakk. 



This paper discussed the distribution of trees 

 and shrubs of the drainage basin of the Missouri 

 River and some of its tributaries. A numher of 

 southern species like Cerois canadensis and Asi- 

 mina triloia, Quercu-s acwninata and Vitis cinerea 

 reach their northern distribution in Fremont 

 County. 



The Weed Flora of ih^ LaTce Superior Begion 

 Compared with the Weed Flora of Iowa: L. H. 

 Pammel. 

 A brief comparative study of the distribution 



of weeds of the northern lake region and the 



prairie region of Iowa. 



Some Comparative Germination Tests of Sweet 



Clover: H. S. Doty. 



A test of the germination of sweet clover treated 

 with sulphuric acid, scratching, freezing and the 

 Hughes method. It was found that scarification, 

 freezing and the acid hastened the germination of 

 seeds. 



Th-e Flora of the Ledges, Boone County, lowat 

 Wm. DiEHL, presented by L. H. Pammel. 

 A systematic catalogue of the spermatophytes 

 and ferns of the ledges comprising a small area of 

 Carboniferous sandstone along Pease Creek, a 

 small stream which empties into the Des Moines. 

 In this region occur a number of species of local 

 range like Querent acuminata, Birca palustris, 

 Juniperus virginiana, Physooarpus opulifolius, 

 Lathyru-s ochroleucus, Trillium nivale, etc. 



Flora of the East Slope of the Cascade Mountains 

 in CrooTc County, Oregon: Morton E. Peck. 

 The paper discusses briefly the general distribu- 

 tion of the flora on a line drawn across the Cascade 

 Mountains in central Oregon, then takes up more 

 in detail the plants occurring on the lower portion 

 of the eastern slope, namely, at the town of Sisters. 

 A study of these indicates that the locality is 



