604 



SCIENCE. 



[N. S. Vol. III. No. 68. 



Formalin in the Field, illustrating his remarks 

 with examples of plants, insects, iishes and 

 reptiles preserved in a mixture of formalin and 

 water. The advantages claimed were cheap- 

 ness, compactness, and the property of pre- 

 serving specimens which could not be kept in 

 alcohol, or could not be kept in such good con- 

 dition. 



Henry H. Dixon and J. Joly, of Trinity 

 College, Dublin, summarized, by request, the 

 results of their Recent Sesearches on the Ascent 

 of Sap in Trees, making the deduction from an 

 elaborate series of experiments that the move- 

 ment was due to a state of tension in the sap 

 induced by osmotic action and transpiration in 

 the leaves. The chief necessary condition for 

 maintaining a state of high tension (several 

 atmospheres) is that the column of water shall 

 not rupture, but to prevent rupture it is not 

 necessary, as has been supposed, that the fluid 

 shall contain no dissolved gas, but that the 

 walls of the containing vessel be completely 

 wet. 



Under the title of the Shade-tree Question from 

 an Instinct Standpoint, L. O. Howard presented 

 a short communication upon the subject of the 

 relative immunity from insects of different 

 varieties of shade trees. He spoke of the ex- 

 traordinary abundance of shade-tree insects in 

 different Eastern cities during the summer of 

 1895, and exhibited specimens of the species 

 which were principally abundant. He further 

 said that in the selection of trees for shade suffi- 

 cient account is not taken of their relative sus- 

 ceptibility to insect attack. He displayed a list 

 drawn up a few years ago by Mr. Fernow for the 

 Brooklyn authorities, in which the trees to be 

 chosen were graded according to endurance, re- 

 cuperative power, cleanliness, beauty and form, 

 shade, duration of life period, rapidity of growth, 

 and persistence; and in comparison with this list 

 he rated the same trees according to their sus- 

 ceptibility to insect attack or their immunity 

 from insect attack. The latter rating showed a 

 somewhat different relative arrangement from 

 the total rating derived from other qualities, and 

 the speaker, while admitting the value of the 

 total relative rating from so many important 

 characteristics, expressed himself as of the 

 opinion that in one or two cases, notably with 



the box elder, extraordinary susceptibility to 

 insect attack renders them practically useless 

 for shade-tree purposes, in spite of their many 

 ■good qualities from other standpoints. 



P. E. L. Beal read a paper on the Food of the 

 Cowbird, Molothrus ater, giving the results of 

 an examination of the contents of 366 stomachs 

 of this species, collected in 20 States and the 

 District of Columbia, and representing every 

 month from March to December inclusive. The 

 food was found to consist of about 28 per cent, 

 of animal matter and 72 per cent, of vegetable. 

 The animal food was composed almost exclu- 

 sively of harmful insects and spiders. The 

 vegetable food consists of 20 per cent, of grain 

 (corn and oats), 51 per cent, of weed seeds and 

 traces of fruit and a few other miscellaneous 

 articles. As at least half of the grain eaten 

 must have been waste, the conclusion is reached 

 that in its food habits the cowbird does far 

 more good than harm. F. A. Lucas, 



Secretary. 



CHEMICAL SOCIETY OF WASHINGTON. 



The eighty-sixth regular meeting was held 

 February 13, 1896, at the rooms of the ' Down- 

 town Club,' and after the transaction of neces- 

 sary business, was devoted to a lunch and 

 social purposes, inaugurating the newly elected 

 president. Dr. E. A. de Schweinitz. The fol- 

 lowing members also were elected: Messrs. 

 Clinton P. Townsend, S. S. Voorhees and Dr. 

 P. K. Cameron. 



A special meeting was held February 21st to 

 hear the Presidential address of the retiring 

 President, Prof. Chas. E. Munroe, the subject 

 being ' The Development of Smokeless Powder.' 

 He first sought to show that the necessity for a 

 high power, smokeless propellant had been 

 created by the mechanical perfection to which 

 ordinance had attained, and the precision of the 

 weapons and instruments by which they were 

 directed; that the possible production of such 

 propellants was dependent upon the discovery 

 of gun cotton, nitro-glycerine and certain nitro- 

 substitution compounds and the improvements 

 in their manufacture; that the possibility of 

 producing uniform and reliable propellants was 

 dependent on the invention of pressure gauges 

 and velocimeters; and that the possibility of 



