224 PROCEEDINGS. 



the smaller Magellan cloud is, by this negative, and eight hours 

 exposure, proved to be — shall we say another Universe — certainly 

 it is another great spiral object, with almost exactly the same 

 form as the greater one ; it is vastly more distant if we may 

 judge its distance by its faintness and its size. The exposures 

 given to these negatives in order to bring out the details of the 

 Nebecuke are, so far as I am aware, the longest yet given to 

 celestial photographs ; and the results obtained are quite as 

 startling as the earlier ones in Europe, which revealed stars and 

 nebulae which never had or could have been seen otherwise than 

 by photography. Photography has here distinctly revealed in 

 the Magellan clouds a spiral structure and a wealth of detail 

 indicating structural arrangement in those far distant Universes 

 which never has, or could be seen with any telescope, for from the 

 very nature of a telescope — and the larger it is the more pro- 

 nounced is this fault — it can only present to the eye small parts 

 of such an object at a time, and hence so to speak, severs the 

 arrangement and continuity of the object in such a way that the 

 eye so aided could never see their mutual interdependence. 



I have brought two other photographs, of interest for very 

 different reasons. The first is of the brightest part of our own 

 Milky Way, "that found in Sagittarius" and which has also been 

 photographed at Lick Observatory, and reproduced in Knowledge, 

 July 1st, 1890. I want to place it on record for comparison to 

 show results obtained with similar instruments (portrait lenses of 

 about six inches aperture), but the one used at an elevation of 

 4,000 feet, and the other in Sydney, and I think you will agree 

 with me in thinking that the Sydney picture shews much better 

 definition than the other. The other photograph includes the great 

 nebula about Theta Orionis, and it was taken to afford a measure 

 of the work I have been doing ; that is, a photograph taken with 

 the same apparatus, plates, &c, as those taken of the Magellan 

 clouds and Milky Way, by which means we can see how very much 

 fainter photographically some of the southern objects are than 

 Orion. Eta Argus for instance, is very much under exposed with 

 three hours exposure, while Orion is very much over exposed in 

 four hours. Compared with those of the Nebeculse Major and 

 Minor, it brings out conspicuously two points: first, its miniature 

 size compared with Nebecula Major ; and second, its intense 

 relative photographic brilliance which makes it much over exposed 

 with four hours, while the others are still under-exposed with 

 seven and eight hours. 



Orion was chosen because conveniently situated for other obser- 

 vatories and because it had been frequently photographed in other 

 observatories. The exposure given on Orion was four hours, and 

 the whole picture of the nebula is spoiled by over-exposure, 



