134 



NA rURE 



[June 6, 1901 



be summed up as follows: — (i) Increased speed for the same 

 boiler-power; (2) absence of vibration; (3) increased cabin 

 accommodation (due to the smaller space required for 

 machinery) ; (4) less upkeep in machinery and smaller engine- 

 room staff. Time alone will prove the increased speed of this 

 vessel and the validity of these advantages claimed over her 

 commercial predecessors. 



An interesting description of the period of activity of Vesuvius 

 in April and May of last year is given by Prof. R. V. Matteucci 

 in the Bollettino of the Italian Seismological Society (vol. vi. 

 No. 7)> ^n<^ one of the illustrations accompanying the paper is 

 here reproduced. The eruption commenced on April 24, and 

 lasted a month. There was no lava flow, but the explosions 

 in the crater were very strong, and reached a maximum on 

 May 9, when they were distinctly heard over almost the whole of 

 Campania. The greatest height reached by the volcanic bombs 

 and scoria; was about 540 metres from the bottom of the crater. 



F 



An expl. 



May, iguo. 



and the largest block ejected had a volume of about twelve 

 cubic metres and a weight of nearly thirty tons. The volume 

 of material thrown out by the volcano during the months of 

 April and May was estimated to have been about half a million 

 cubic metres. For three days Prof. Matteucci remained near 

 the crater of Vesuvius, and on one occasion was fortunate 

 enough to witness an explosion which surrounded him with 

 falling scoria; and lapilli without injuring him, though the erup- 

 tion destroyed his photographic apparatus. His observations 

 upon the appearance of the crater during incandescence and 

 the character of the volcanic products are of much interest. 



An aid to the scientific pursuit of photography is afforded by 

 the "Chapman Jones Plate Tester" produced by Messrs. 

 Sanger Shepherd and Co. This new photographic accessory 

 NO. 1649, VOL. 64] 



consists essentially of a series of graduated transparencies, a 

 colour sensitometer, and a series of colours — each including one 

 definite region of the spectrum. All these are on one plate and 

 are arranged to show at a glance (i) sensitiveness of ordinary 

 plates, (2) the added sensitiveness of isochromatic .plates, (3) 

 the further added sensitiveness of red sensitive plates, this last, 

 being in two parts, distmguishing between the more and the 

 less refrangible than the Fraunhofer line C. The graduated 

 series gives a quantitative value to the colour tests : without it 

 a series of exposures would be necessary, and the result even then 

 would be indefinite. By a single exposure and development 

 the screen gives .a quantitative expression of all the properties 

 of photographic plates that are generally of use. Moreover, 

 the record thus obtained can be preserved for more critical 

 examination at any future time, when exact measurement with 

 a photometric arrangement or opacity meter will give results 

 probably as accurate as could be obtained by any method of 

 testing. A plate tester having these joint merits of simplicity 

 and accuracy should prove of service to photographers who base 

 their art upon scientific principles. 



" Prosi'ECI ING for Gold in County Wicklow " is the title of 

 a paper by Mr. E. St. John Lyburn in the Proceedings of the 

 Royal Dublin Society (vol. ix. new ser. part 4, 1901). The 

 author gives the results of numerous assays of samples of quartz, 

 grit, &c. , and in one instance records 4 dwts. per ton from a 

 specimen obtained near the summit of Croghan Kinshelagh. The 

 owner of the estate unfortunately objected to prospecting and 

 Mr. Lyburn had to abandon his work without settling whether 

 or not Wicklow contains gold in payable quantity in the rocks. 

 He observes that panning for gold is secretly carried on in the 

 county and is apparently lucrative to those interested ; and he 

 urges further researches on Croghan Kinshelagh mountain, more 

 especially at the junction of the diorite rocks and the Sihirian 

 formation. 



The Jurassic Brachiopoda of Cutch form the subject of an 

 important monograph by Dr. F. L. Kitchin (Mem. Gepl. 

 Sum. India, ser. ix. vol. iii. part i, 1900). The task under- 

 taken by the author was one not unattended by difficulties, as 

 many years have elapsed since the fossils were collected, and 

 their geological horizons were not in all cases satisfactorily 

 determined. He has, however, received much aid in deciding 

 these matters from Prof. J. F. Blake, who not very long ago 

 personally studied the region. A superficial glance at the plates 

 would lead one to suppose that many British species of Inferior 

 Oolite and Great Oolite Brachiopoda were represented, such 

 as Terebratttla Phillipsi, T. globata, T. maxillata, &.C. ; but 

 although there are forms which appear to show afSnity to British 

 species belonging to different Jurassic divisions, yet such forms 

 occur together in Cutch strata, and correlation becomes impossible 

 when the forms on one horizon suggest Bajocian, Bathonian and 

 Callovian ages. Most of the specimens now figured by Dr. 

 Kitchin receive new names, even where the resemblance to a 

 European form is great. This has been done in the belief that 

 the application of the term " variety " is not admissible in cases 

 where the direct relationship to the " species " either cannot 

 be definitely proved or does not appear highly probable. It 

 is satisfactory to learn with regard to Brachiopoda " that to a 

 certain degree, the larger the number of individuals with which 

 we have to deal, the fewer ' species ' shall we find them to 

 represent." It would have been oetter if the author had had the 

 benefit of a series of specimens from a more clearly established 

 stratigraphical sequence, but that he has made the best use he 

 could of the material will not be questioned, and his illus- 

 trations are excellent. The fauna as a whole has a distinct facies 

 and is without precise parallel in the European area. 



