Dki^kmdcr 4, 190;!. 



SCIENCE. 



72'.) 



DIBCUSSIOX .4.VD C0RBE8I'0M>K\rE. 



A VISUAL PHENOMENON". 



To THK Editor of Science: Dr. (imild's in- 

 torcstiug statement cuneerning a ' liitherto 

 undescribeil vi.sual phenomenon ' induces nie 

 to add the fnllowing note. In 1S97 during a 

 month's inspection of the Ural region under 

 the auspices of the Russian government, our 

 special train stopped one night on a side track 

 near a station on the Siberian border. Some 

 of our party were attending an entertainment 

 given at some distance and expected to return 

 on foot during the night, which was dark, with 

 a slight drizzling rain. At about ten o'clock 

 I was watching, tlirough a glass window in the 

 rear of the car, a light which 1 supposed to be 

 a lantern in the hands of my returning fellow 

 travelers. There was no other light visible, 

 and as I looked, it seemed evident that the 

 light was descending the face of a far sloping 

 hill reaching to the railway; but the motion 

 wass by a series of lateral jerks first to the 

 right and again to the left, each excursion, 

 however, bringing it, apparently, lower and 

 nearer. At first the motion amused me, later 

 it interested me, and when, after steadily ob- 

 serving the phenomenon for a considerable 

 time, I found the light had actually not moved 

 from the spot where I first .saw it, 1 was 

 astonished. In this frame of mind my friend. 

 Professor I. C. White, found me, and not be- 

 ing able to see what I described, doubtless 

 formed an opinion of me as unjust as mine 

 was of the supposed revelers who seemed to be 

 coming home in a decidedly zig-zag course. 

 On my return to Philadelphia I described the 

 phenomenon to Dr. de Schweinitz and others. 

 I found I could reproduce the delusion at will 

 by looking from any dark place at a single 

 light; as, for instance, on a cloud.y night from 

 the sea beach at the distant light of a ship on 

 the horizon. Whether looked at with one eye 

 or with two, tlie light alway.*; gives the im- 

 pression of moving by jerks either sidewise or 

 vertically, but in the former case it always 

 seems to progress slowly downward or up- 

 ward. 



Under the conditions above described the 

 phenomenon appears not to be controllable by 

 tho will. PER.SIFOR Frazer. 



SIIOJ{ri:ii A IITWLES. 



CORTICIIM V.\f;lM B. AND C. VAR. SOLAM BI'RT. 

 A FRUITINC STACiE OF RIIIZOCTONIA SOLANI. 



A sTLOY of the Jihizoctonia of the potato 

 was begun by the Colorado Experiment Sta- 

 tion in the spring of 1901. It soon became evi- 

 dent that it is not a sterile fungus and mucli 

 time has been given to the discovery of a fruit- 

 ing stage. Observations show that potato plants 

 developed from tul)ers which are more or le.s.s 

 covered with .sclerotia of this fungus usually 

 have their subterranean parts overrun with a 

 <lark brown cobweb-like mycelium. This cov- 

 ering frequently extends up the green stems 

 from one to three inches above the ground, 

 forming a thin liynienial layer which is usually 

 gray-white in color. This layer docs not 

 adhere firmly to the stem and cracks very 

 easily when it becomes dry, consequently it 

 disappears soon after the death of the plant. 



The tip of the outermost branches of this 

 hjTnenial layer become changed into basidia, 

 bearing from two to six sterigmata. The 

 spores arc hyaline, and usually ovate in form, 

 with apiculate bases. Fifty spores taken just 

 as they occurred on a green stem gave an 

 average mea.stirement of 10 by 6/<.. But 

 spores after they had fallen averaged 12 by 

 8 //. Thus far a pure culture of this fungus 

 has not been obtained directly from spores, 

 but cultures made from the hymenial layer 

 invariably produce a luxuriant growth of 

 Rhizoctoiiiii. 



The main character of this green stem form 

 agrees with Corticlum vnt/iim B. & C, but on 

 account of the spore differences and parasitic 

 mode of life, it has been thought wise to make 

 a variety of this form for which Dr. E. A. 

 Burt has .suggested Corliciiim vagum B. & C. 

 var. solaui. It also agrees closely with the 

 description of Ilypnochns solani Prill & Del, 

 and they may eventually prove to be the same. 

 Fort Collins, Colo., F. M. Rolfs. 



October 19, 1903. 



HKNI LTS OF THE RESURVEY OF LONG ISLAND, NEW 

 YORK.* 



NoTwiTiLSTANDiNfi Loug Island has been 

 many times studied by geologists a considerable 



* Published by pt-rmission of tlie Director of tlie 

 I'nilpd States Geological Siirvev. 



