170 



SCIENCE 



[N. S. Vol. XL VII. No. 1207 



only reason for th.e reply recently given by 

 the government in the House of Conunons to 

 a question regarding legislation for the crea- 

 tion of a Ministry of Public Health. He ap- 

 pealed, therefore, to all interests concerned to 

 sink minor differences and to approach the 

 problem of public health administration as a 

 whole from the broad national standpoint and 

 in a courageous spirit. 



EDUCATIONAL NOTES AND NEWS 



A COMMITTEE Consisting of Eegent Schulz 

 and Deans Thatcher and Vance has been ap- 

 pointed to plan the celebration of the fiftieth 

 anniversary of the establishment of the Uni- 

 versity of Minnesota. The inauguration of 

 President Burton will be one of the chief 

 features. In view of the war conditions the 

 celebration is planned to be of state interest 

 only. 



The Harvard summer engineering camp at 

 Squam Lake, N. H., has been abandoned on 

 account of the war and owing to the fact that 

 the expenses of the camp can not be met unless 

 more than the thirty students already reg- 

 istered attend. 



At Louisiana State University, Assistant 

 Professor S. T. Sanders has been made head 

 of the department of mathematics, and Dr. 

 I. C. Nichols has been apiwinted associate 

 professor. 



Mr. Eot Eichaed Denslow, assistant tutor 

 in the department of chemistry. College of the 

 City of !N"ew York, has been appointed in- 

 structor in Smith College. 



DISCUSSION AND CORRESPONDENCE 



LUMINOSITY OF RECTIFIER ELECTRODE 



To THE Editor op Science: In setting up 

 as a demonstration experiment, the well-known 

 arrangement for rectifying an alternating 

 current, the essential part of which is an 

 aluminum rod and lead plate in ten per cent, 

 sodium phosphate solution, the following ob- 

 servation was made, which may be well known 

 but which I wish to take this opportunity of 



mentioning, since I have not found it de- 

 scribed anywhere in connection with the ex- 

 periment. 



When the aluminum rod is positive, that is 

 to say, when the current is in such direction 

 that it will not pass through the rectifier, a 

 very distinct luminosity appears over the sur- 

 face of the aluminum and if the applied po- 

 tential is as high as 250 volts, this luminosity 

 becomes quite brilliant enough to be observed 

 by a spectroscope. This is not due to local 

 heating since the aluminiam is only gently 

 warmed. The glow is orange yellow in color 

 and, through a direct-vision spectroscope, 

 shows a continuous si>ectrum through the 

 red, yellow and green with a trace of blue. 

 Phosphorescence is suggested, possibly similar 

 to that shown by alum. 



May I lay this before your readers in the 

 hope that some one of them may be familiar 

 with, and have an explanation for, this lumin- 

 osity. Our time at present is so taken up 

 with other matters that investigation of it 

 can not be pushed as would otherwise be the 

 case. 



Haevet B. Lemon 



Eteeson Physicai Laboratory, 

 University op Chicago 



an unusually brilliant halo 

 To THE Editor of Science: The very com- 

 plete halos visible at Boulder, Colo., on the 

 morning of January 10, 1918, are i)erhaps 

 worthy of a brief description 



The phenomena were first observed when the 

 sun was about 10° or 12° high. At this time 

 all of the 22° halo that was above the horizon 

 was very distinct. The white horizontal par- 

 helic circle extending each way from the sun 

 to a short distance outside the 22° halo was 

 also plainly marked and the parhelia where it 

 crossed the halo were very bright, though 

 somewhat diffuse. In about half an hour the 

 22° halo became much brighter showing red 

 on the inside and a faint blue on the outside. 

 Above the sun, tangent to this halo and con- 

 vex toward the sun, api)eared the usual ox- 

 yoke-shaped arc of a pale pink tinge. During 

 this time also the 46° halo appeared and be- 



