TRANSACTIONS OF SECTION A. 751 
than has yet been accomplished ; if, indeed, the present meeting will extend to him, 
among the annual votes for the promotion of science, a sufficient one for carrying on 
an end-on-gas-vacuum-tube method of photographing, which is alone suitable to 
high spectroscopy. 
12. On Meteorological Photography. 
By Joun Horxinson, F.L.S., F.G.S., FR. Met. Soc. 
The author called attention to the increasing importance attached to photo- 
graphy as a means of illustrating scientific subjects and aiding in scientific research. 
In no branch of science, he thought, could photography be of greater value than in 
meteorology, owing to the transient nature of meteorological phenomena. 
The appointment of a Committee of the British Association on Meteorological 
Phenomena, by which committee instructions to photographers would be issued 
with the view of instituting a systematic method of working, &c., would, he felt 
sure, greatly extend the interest taken in the subject and increase the scientific 
value of the results. The chief object of such a committee would be to investigate 
and report upon the means by which photography can most advantageously be 
applied to the elucidation of meteorological phenomena, such as the forms of clouds, 
lightning flashes, and the effects of storms. The committee would also undertake 
the collection of photographs of such phenomena and keep a register of them, 
reporting additions annually, and would compile a bibliography of the subject. 
In the study of the various forms of clouds, the author believed that a satisfac- 
tory classification could best be made by the comparison of numerous photographs ; 
the relation between cloud forms and atmospheric pressure and temperature 
would be an interesting field for research; and an attempt might be made to 
ascertain the best means of overcoming the difficulty of photographing light clouds 
on a blue sky, due to blue rays being almost as powerfully actinic as white. 
Tn the investigation of lightning by photography special attention would be given 
to the phenomenon of the appearance on the plate of so-called dark flashes, with 
the object of arriving at a conclusive explanation of the effect, and an endeavour 
might possibly be made to determine whether lightning really forms a streak or 
a point in excessively rapid motion. The collection and exhibition of photographs 
_ showing the destructive effects of storms—whether the destruction or damage 
were wrought by rain, by wind, or by lightning—might not be considered of such 
scientific importance as the investigation of clouds and lightning, but it would add 
much to the general interest of the inquiry.’ 
13. On the Spectra of the Elements and the Constitution of the Sun. 
By Professor H. A. Rownanp. 
14. On Regional Magnetic Disturbances in the United Kingdom. 
By Professors A. W. Ricxrr, /.R.S., and T. E. Tuorrz, F.R.S. 
15. Sur les perturbations magnétiques en France. 
By Professor H. Mascarr. 
16. Hehibition of Photographs of Clouds. By Frinsr GREENE. 
1 The Committee here suggested was appointed. 
