TRANSACTIONS OF SECTION A. 667, 



have already mentioned the occasional ascents conducted by Mr. Alexander with 

 unmanned balloons, but I hope that we shall likewise have the permanent assist- 

 ance of the great British Empire. The foundation of an aeronautical observatory 

 and a kite station on these shores is of the greatest importance for our studies. 

 With the help of ship-motion it would be possible to send up self-recording 

 instruments every day. I have seen, not without emotion, here in the exhibition, 

 those classical instruments which were used many years ago by your celebrated 

 James Glaisher, whom we are proud to have had on the list of our honorary 

 members. They are to me a sure sign that English science, remembering his 

 great services, will take a prominent place in our aeronautical investigation of the 

 upper atmosphere. 



7. Photographs of the Orion Nebula. By W. E. Wilson, F.R.S. 



It is not possible to produce from a long exposure negative of the Orion 

 nebula a direct positive which will show at once both the detail in the bright 

 central portions and the faint extensions. The author has succeeded, by means of 

 screening off gradually the outlying portions, in obtaining the desired result, 

 and suggests that the method is in some ways preferable to the method of local 

 reduction of the original negative. 



8. Lightning and its Spectra. 

 By W. J. S. LocKYER, M.A., PhD., F.R.A.S. 



This paper consists of a brief reference to the different types of lightning 

 flashes, such as multiple, band, &c., and an account of the method adopted by the 

 author in securing their spectra. He showed that by the use of small hand or 

 stand cameras, with the addition of a Thorpe transparent grating placed before the 

 objective, not only could the spectra of bright flashes be secured, but an image of 

 the flash in each case obtained. Two flashes with their spectra were shown, the 

 latter showing in one case not only bright but apparently dark lines. These photo- 

 graphs, together with others, were obtained by the author on the morning (8 a.m.) 

 of May 31, 1903, using in one case a 5 x 4 Cartridge Kodak, and in the other a 

 8i X 6| Dallmeyer rapid rectilinear attached to a box camera. Both spectra, which 

 resembled each other to a great extent, differed from those .^secured by Professor 

 E. C. Pickering. He then illustrated different photographs of the spectra of sparks 

 in air taken with the same instrument, showing the changes in the spectra as the 

 air was varied by the addition of small quantities of nitrogen or oxygen, or by 

 allowing a great number of discharges to occur before analysing the spectrum. A 

 comparison of these spectra was then made with those of the actual lightning 

 flashes. The author expressed no definite results of this comparison, as the inves- 

 tigation was not yet completed. 



9. On the Phenomena accompanying the Volcanic Eruptions in the 

 West Indies. By David Burns, C.F. 



Armstrong's hydro-electric machine was in its day unrivalled as a source of 

 high electric power. Faraday ascribed the electricity to the friction of the 

 particles of water in the issuing steam against the sides of the jet. The author sup- 

 poses that electricity was likewise created in immense quantity by the friction of 

 steam and ash against the sides of the vent of the volcano during the eruptions, 

 and that Mont Pelee and La Soufriere have in their composition beds of low con- 

 ductivity, so that the mountain becomes intensely electrified, and also the clouds of 

 steam and ash over them. The two theories that have been put forward of the 

 ' blast ' are discussed ; the explosive cloud theory is considered untenable, and 

 calculations are given to show that the gravitation theory of the British Scientific 

 Expedition is inadequate. The ' blast ' is ascribed by the author to the repulsioq 



