552 



SCIENCE, 



[N. S. Vol. XI. No. 275. 



however, being so in only a few of its genera. 

 The 11 highest families are very peculiar. 

 While mostly regular, some of them are noted 

 for irregularity, but this is so peculiarly ad- 

 justed in the inflorescence as to bring about the 

 condition of regularity so far as the latter is 

 concerned. Thus the daisj^, while an inflor- 

 escence, is essentially a regular flower, by vir- 

 tue of the arrangement of its irregular florets. 

 ■It is also noticeable that as these raj' flowers 

 are usually pistillate, this arrangement reverses 

 the position, so far as the head is concerned, of 

 the distinctively pistillate portion. The vari- 

 ous types of irregularity in composite flowers 

 were discussed, and these were contrasted with 

 other families exhibiting radiant inflorescences. 

 It was pointed out that irregularity was not 

 a fundamental characteristic, but was readily 

 called into existence by the exigencies of any 

 group, or even species, and might be expected 

 to develop anywhere. Special attention was 

 called, as illustrating this principle, to the 

 marked irregularity of Cotyledon gihhiflorum 

 and Saxifraga sarmentosa, species in notably 

 regular genera. It was also noted as signifi- 

 cant that the most irregular families, such as 

 Legumincsae, might have extensive series of 

 genera perfectly regular ; also that almost ex- 

 actly equal forms of irregularity might develop 

 in families most widely separated, as the Li- 

 liacese and the Capparidacese. The fact that 

 irregularity is more frequent in the higher 

 families of the two classes is due to the fact 

 that an essential property of such families is a 

 greater power of adaptation, floral irregularity 

 being only one manifestation of this character. 

 Edward S. Burgess, 



Secretary. 



THE ACADEMY OF SCIENCE OF ST. LOUIS. 



At the meeting of the Academy of Science of 

 St. Louis of March 19, 1900, fifty-eight. persons 

 present, Dr. H. von Schrenk exhibited some 

 burls on the white spruce {Picea Canadensis). 

 The burls, unlike most of those so far known, 

 are almost round, and are covered with smooth 

 bark. They grow of various sizes, and occur 

 on the trunk and branches of a group of spruces 

 limited to a small area. The wood fibres are 

 arranged in annual rings; they differ from nor- 



mal wood fibres because of their thinner walls 

 and greater internal diameter, giving the wood 

 a spongy character. Long rows of secondary 

 resin passages occur in each ring. The largest 

 burls, which are from one to three feet in di- 

 ameter, have rows of long holes within each 

 ring. These holes are diamond-shaped in 

 cross-section, the longer diameter extending 

 radially. Between the holes the wood fibres 

 are compressed tangentially. The speaker ex- 

 plained that the holes must have resulted from 

 an excessive radial pressure exerted from with- 

 out, probably by the bark. No holes were found 

 where the bark pressure had been released, i. e., 

 where the bark had burst. These results are 

 not in harmony with the findings as to bark 

 pressure reached by Krabbe. The speaker de- 

 scribed the manner in which burls are usually 

 formed, and showed the way in which these 

 burls form, by excessive growth, induced by a 

 wound or branch stump. 



Professor F. E. Nipher exhibited stereopticon 

 slides made from a large number of photo- 

 graphic negatives which had been taken by the 

 electric spark from a Holtz machine. The neg- 

 atives show a complete picture of the object 

 acted upon by the spark, and also show the 

 electrical radiations in the field around the ob- 

 ject photographed. The plates were greatly 

 over-exposed to light before they were used. 

 They were allowed to lie fully exposed In a 

 well lighted room, for from one to nine days. 

 One of the best negatives was developed from a 

 plate thus exposed for nine days. The best re- 

 sults are obtained by darkening the room when 

 the electrical image is produced. Light is found 

 to counteract the electrical effects when their 

 action is simultaneous and also when it follows 

 the electrical exposure. 



The pictures are developed in the dark room, 

 by the light of an incandescent lamp. When 

 the negative begins to fog, it is taken nearer to 

 the lamp, and it at once clears up. All of these 

 methods are in total disregard of all ordinary 

 photographic procedure. The plates used are 

 extra rapid, and the developing solution is that 

 in common use in photography. 



The result which is most interesting from a 

 scientific point of view is shown on twelve neg- 

 atives which reveal ball lightning effects. Ball 



