1886.] 



Presents. 



471 



inclined to consider that the result tends to show that a 'practical 

 method of obtaining photographic records of the corona during sun- 

 light is not likely to be obtained. The trial was not conclusive 

 because the conditions were very unfavourable. In order to reduce 

 the air-glare to a minimum, so that the light of the corona shall not 

 be overpowered, the following points must be observed : — 



1st. The air should be clear and dry. 



2nd. The sun should be near the zenith. 



3rd. The station should be at a considerable elevation above the 

 sea. 



4th. The corona, if it does vary in intensity, should be at its 

 maximum brightness. 



Now every one of these conditions was unfavourable. The air was 

 saturated with moisture, the sky was of a hazy blue, the sun was 

 low, the station was near the sea-level, and the corona according to 

 the general impression was not so bright as on other occasions. 



I hope, however, to deal more fully with the considerations on 

 another occasion. 



The Society adjourned over the Christmas Recess to Thursday, 

 January 6th, 1887. 



Presents, December 9, 1886. 



Transactions. 



Baltimore : — Johns Hopkins University. Studies from the Bio- 

 logical Laboratory. Yol. III. No. 8. 8vo. Baltimore 1886. 



The University. 



Cambridge, Mass. : — Harvard College. Bulletin of the Museum of 

 Comparative Zoology. Vol. XII. No. 6. 8vo. Cambridge 

 18S6. The Museum. 



Harvard University. Bulletin. Yol. IY. No. 6. 8vo. 1886. 



The University. 



Frankfort : — Naturforschende (resell schaft. Abhandlungen. Band 

 XIY. Heft 1. 4to. Frankfurt 1886. The Society. 



Leipzig : — Konigl. Sachs. Gesellschaft der Wissenschaften. Ab- 

 handlungen. Band XIII. Nos. 6-7. 8vo. Leipzig 1886. 



The Society. 



Newcastle : — Institute of Mining and Mechanical Engineers. Trans- 

 actions. Yol. XXXY. Part 3. 8vo. Newcastle 1886. 



The Institute. 



New York : — American Geographical Society. Bulletin. 1882, 

 No. 6; 1883, No. 7; 1884, No. 5; 1886, No. 1. 8vo. New 

 York. The Society. 



