October i i, 1894] 



NA TURE 



579 



The services of photography to art were next touched 

 upon by Sir H. T. Wood, who afterwards went on to say : 



" The interesting investigations of Buchner and Mar- 

 shall Ward into the action of light on bacteria can hardly 

 with justice be admitted as adding to the list of photo- 

 ijraphic materials, though we must certainly claim the 

 ' photobacteriograph ' as an advance in our science and 

 as suggesting new directions for photographic work. 



"The question of sensitometry has exercised the minds 

 of many of our most active workers for some time, but I 

 think I may say without as yet any positive result. I 

 believe I may put it as the opinion of those best qualified 

 to express an impartial judgment on the subject, that 

 while we have certainly obtained a means of roughly 

 gauging the comparative sensitiveness of plates, and 

 have got a guide of great practical use to the makers and 

 users of plates, we are as far as ever from an absolute 

 standard, and that the attainment of such a standard 

 must await the attainment of a standard of light, a pro- 

 blem the solution of which is of importance not to 

 photographers alone. 



" It would obviously be unreasonable to expect that 

 the increase of photographic knowledge shou'd grow 

 pari passu with the number of those who practise the art, 

 but I think it is certainly a matter for regret that of the 

 many thousands who have taken up photography as a 

 pastime, so very few pursue it in a serious way, or in a 

 scientific spirit. The popularisation of photography has 

 indeed to my mind been a drawback to real progress. 

 The process of picture-making has been rendered so 

 easy that it has been deprived of much of its interest, 

 even to the merest amateur in science, and the attention 

 of those who might have pursued photography seriously 

 has been diverted to other branches of science. Still we 

 are fortunate in having, even among the younger workers, 

 a considerable band of capable and active students who 

 are adding slowly but surely to our knowledge of the 

 scientific principles of the art. 



" In photographic optics there is, I think I may say, a 

 very distinct advance now going on. 1 he expectations 

 of opticians have long been fixed on the productions of 

 the Jena manufactory, and those expectations are, ac- 

 cording to the best information at my disposal, now in a 

 fair way of being realised. The qualities of glass that 

 are to be obtained commercially from Jena have pro- 

 vided the opticians with new possibilities for the improve- 

 ment of photographic lenses. Both in this country and 

 in Germany opticians are availing themselves of these 

 possibilities. Great credit is certainly due to Messrs. 

 Ross, who have carried out the work of Dr. Schroeder, 

 and have produced from his calculations the lens which 

 they have termed the 'concentric' lens. The double 

 anastigmat of Goerz, described last year to the Society 

 by that gentleman, is another new lens, the outcome of 

 the Jena improvements in glass, -which ought at least to 

 receive mention. 



" Mr. Uallmeyer has also made considerable advances, 

 both theoretical and practical, in his ' telephotographic ' 

 lens, an instrument which produces results appealing at 

 once to all who take any interest in photographic mat- 

 ters, and one which, in the opinion of competent autho- 

 rities, is likely to have important practical applications 

 for astronomical and other branches of scientilic photo- 

 graphy." 



WILLIAM TOP LEY, F.R.S. 



A GREAT gap has been made in the ranks of active 

 •'*• geologists by the death of William Topley, which 

 took place on the night of Sunday, September 30, at 

 his house at Croydon. He was taken ill, with gastritis, 

 probably from the use of contaminated water, in 

 .Algiers, during a short visit, made in reference to its 

 geology ; and he fell, therefore, in the fighting line of those 



NO. 1302, VOL. 50] 



who apply their scientific knowledge for the good of 

 mankind. 



He was ill whilst travelling home, and though after a 

 time he began a slow recovery, a relapse came on 

 Saturday, September 29, which soon proved fatal. 



Born at Greenwich in 1S41, he had reached an age 

 when, though the physical powers may have begun to 

 wane, yet the mental powers are reinforced by stores of 

 knowledge and of experience, and the value of a scientific 

 life is high. 



His scientific education was at the Royal School of 

 Mines, Jermyn Street. Soon after his student-life was 

 ended, he joined the Geological Survey (early in 1862), and 

 his future career was identified with that Survey, of 

 which he was one of the oldest and best-known officers 

 at the date of his untimely death. 



For many years his work lay in the counties of Kent, 

 Surrey, and Sussex, in the investigation of the great dis- 

 trict of the Weald and its surroundings, with which his 

 name will ever be linked. 



He made his mark as a good observer of facts and an 

 able reasoner from them in 18^15, by the paper, read to 

 the Geological Society, " On the Superficial Deposits of 

 the \'alley of the Medway, with Remarks on the Denuda- 

 tion of the Weald," which was written jointly with his 

 then colleague. Dr. C. LeNeve Foster. This is a most 

 important essay, in which the general question of inland 

 erosion is discussed, and the special question of the pro- 

 cesses of denudation that had acted over a definite tract, 

 on which much had been written, may be said to have 

 been practically settled, an achievement of no small 

 merit. 



In 1S66 Mr. Topley supplemented his knowledge of 

 our Wealden deposits by a visit to the Boulonnais, a 

 tract that really contains the severed eastern end of the 

 Weald, a visit in which the writer had the pleasure of 

 accompanying him, and the results of which were given 

 to the Geological Society in 1S6S. 



He soon turned his attention to the bearings of geology 

 on other branches of knowledge, and in 1S71 the Royal 

 Agricultural Society published a paper by him, " On the 

 Comparative Agriculture of England and Wales," fol- 

 lowed, in the next year, by another, " On the Agricul- 

 tural Geology of the Weald." 



In 1S73 a paper was printed by the Anthropological 

 Institute, in which he treated of the relation of parish 

 boundaries to great physical features. This was illus- 

 trated chiefly from parts of the Weald and its borders ; 

 but references were made to other parts, and amongst 

 them to Northumberland, to which county he had been 

 transferred from the south. 



In 1S74 he gave the Geological Society a very sugges- 

 tive paper "On the Correspondence between some Areas 

 of.'\pparent Upheaval and the Thickening of Subjacent 

 Beds," in which he pointed out that an apparent dip 

 (over a large tract) may be partly owing to the thinning 

 of beds underground. 



In 1 87 5 appeared the work by which he will probably be 

 best known, and in the writing and compiling of which 

 he may be said to have raised his own monument. The 

 Geological Survey Memoir on the Weald is noted, not 

 so much for local details (of which, however, there are 

 many) as for the thorough way in which the literature of 

 the subject is treated, for the full discussion of the sub- 

 jects of physical geology, scenery, and denudation, and for 

 the attention given to many branches of applied geology. 

 The parts mentioned indeed take up more than half of 

 the text, adding greatly to the interest of the book. 



Naturally the important work of the Sub-wealden 

 Boring was not done without Mr. Topley's help. 



In 1S76, he used his northern experience in the field in 

 joining his friend Prof. Lcbour in a paper to the Geologi- 

 cal Society, on the intrusive nature of the Whin Sill, 

 published the following year. 



