June 14, 1900] 



NATURE 



167 



was at a distance of six feet, and the light reflected from the 

 mirror was brought to a focus by this lens, passing through the 

 object on its way. An image of the lamp was formed in space 

 and viewed by the microscope. A little strip of thin brass, with 

 a carefully cut straight edge, was fastened to the stand carrying 

 the bull's eye condenser, and moved into position between the 

 objective and object so as to cut off the flame-image with the 

 exception of a narrow thread of light along the straight edge. 

 The brass screen must be in the plane of the flame-image, with 

 its edge parallel to the straight edge of the flame. The brass 

 was then advanced over the flame until nearly all the light was 

 cut off. Upon lowering the microscope until the object was in 

 focus, and carefully advancing the brass strip until practically all 

 the flame-image was cutoff, it was found that the glass particles 

 suddenly appeared with great sharpness, showing as distinctly as 

 if in air. Two photographs of glass in oil were shown, one 

 taken with ordinary illumination, and the other by the Schlieren- 

 Methode. 



Geological Society, May 23.— J. J. H. Teall, F.R.S., 

 President, in the chair. — The igneous rocks of the coast 

 of County Waterford, by F. R. Cowper Reed. The first 

 part of this paper is devoted to a discussion of the field - 

 evidence, as shown by the coast-sections from Newtown Head 

 to Stradbally. The igneous rocks there exposed are divided 

 into the following five categories : — {a) The felsitic rocks ; (fi) 

 necks of non-volcanic materials ; (t) the basic sills and vents ; 

 {d) intrusions of dolerite ; {e) intrusions of trachyte, andesite, 

 &c. ; (/) intrusions of other types. In regard to the age of the 

 rocks, there appear to have been two main periods of volcanic 

 activity : the first, in Ordovician times, was marked solely by 

 outpourings of a felsitic nature ; the second, post-Ordovician but 

 pre- Upper-Old-Red-Sandstone, was characterised by a succes- 

 sion of several distinct types of igneous rocks. The relative age 

 of some of the peculiar types of intrusive rocks is indicated in 

 the paper in those cases in which it can be determined. That 

 those rocks which are later in date than the folding of the 

 Ordovician are older than the Upper Old Red Sandstone is 

 shown (i) by the unconformity of the Upper Old Red Sand- 

 stone ; {2) by the fact that the latter rock does not contain any 

 interbedded igneous rocks ; and {3) by the absence of felsitic or 

 other intrusive rocks from the Old Red Sandstone of the district. 

 The second part of the paper is devoted to petrological notes on 

 the different rock-types.— -On a new type of rock from Kent- 

 alien and elsewhere, and its relation to other igneous rocks in 

 Arg>-llshire, by J. B. Hill, R.N., and H. Kynaston. [Com- 

 municated by permission of the Director-General of H.M. 

 Geological Survey.] A rock originally described by Mr. Teall 

 from Kentallen is used by the authors as a type round which 

 they group a peculiar series of basic rocks discovered in several 

 localities. The rocks consist essentially of olivine and augite 

 with smaller amounts of orthoclase, plagioclase and biotite, 

 while apatite and magnetite are accessory. The peculiar feature 

 of the rocks is the association of alkali- felspar with olivine and 

 augite, and the group is related to the shonkinite of Montana 

 and the olivine-monzonite of Scandinavia, 



Anthropological Institute, May 29.— The President in 

 the chair.— Prof. Oscar Montelius, of Stockholm, made a com- 

 munication on the earliest communications between Italy and 

 Scandinavia. Beginning with the evidence derived from the 

 discovery, in Denmark and Central Europe, of bronze bowls and 

 other objects of Roman date, coming from the workshops in 

 Italy, as similar to examples found at Pompeii and elsewhere, he 

 traced the active and copious intercourse thus demonstrated, 

 step by step backwards in time through the period of early 

 Greek commerce at the beginning of the Iron Age in the Medi- 

 terranean, into the later and earlier Bronze Age ; and illustrated 

 his conclusions by a variety of classes of objects, which though 

 originally of Italian origin and manufacture are found widely 

 distributed in Central Europe, in Denmark and in Sweden ; 

 and can be shown by numerous examples to have been imitated 

 by the bronze working industry of these northern areas. Among 

 these objects, he regarded the attenuate sword-hilts and the 

 bucket-like iituloe as demonstrating this intercourse for the 

 early centuries of the first millennium B.C. ; the transversely- 

 grooved sword-hilts, and the simple bow -fibula as proving the 

 same for the later half of the second millennium, corresponding 

 with the Mycenrean Age in the Mediterranean ; the triangular 

 dagger-shaped blades, and the imitations of open spiral torques 

 and bracelets, as representing the earlier half of the same ; 



NO. 1598, VOL. 62] 



and the rude hour-glass shaped types of cups and vessels as 

 carrying the same argument back beyond the date 2000 B.C. — 

 The paper was followed by a discussion. 



Paris. 

 Academy of Sciences, June 5. — M. Maurice Levy in the 

 chair. — The eclipse of the sun of May 28, 1900, at Paris, by M. 

 Loewy. The observations were interfered with by the state of 

 the sky. — Total eclipse of May 28, by M. J. Janssen. An 

 account of the work done in Spain by observers from the Obser- 

 vatory of Paris. — On the calo/ific equilibrium of a closed surface 

 radiating outwardly, by M. Emile Picard. — Observation of the 

 solar eclipse of May 28 at Marseilles and Algiers, by M. Stephan. 

 As the atmospheric conditions were extremely favourable at 

 these two stations, good observations of the times of contact, and 

 of the corona and solar protuberances, were taken. — Observations 

 of the partial eclipse of the sun of May 28 at the Observatory of 

 Bordeaux, by M. G. Rayet. — Observations of the planet (FG) 

 (Wolf-Schwassmann, May 22), made with the large equatorial of 

 the Observatory of Bordeaux, by MM. G. Rayet and Feraud. — On 

 the curve of rifling in fire-arms, by M. Vallier. — The formation 

 of the coal-measures, by M. Grand'Eury. In contrasting the 

 two theories current for explaining the formation of coal deposits., 

 the drift theory and the peat bog theory, the author cites in- 

 stances in which, from his own observations, both influences 

 must have been at work simultaneously. — The total eclipse of 

 the sun of May 28 observed at Hellin, in Spain, by M. Hamy. 

 The observations, which were entirely successful, include seven 

 photographs of the corona. The characteristic green line of 

 the corona, although falling within the sensitive region of the 

 orthochromatic plates employed, gave no trace of impression 

 in the spectrum photographs. — The total eclipse of the sun of 

 May 28. Observations made at the Observatory of Algiers, by 

 M. Ch. Trepied. The plan of operations included observations 

 of the four contacts, visual study of the corona, photography of 

 the partial eclipse, photography of the corona and of the 

 spectrum of bright lines in the chromosphere, the photo- 

 graphy of the spectrum of the corona, and thermo-actinometric 

 observations. Under the very favourable atmospheric conditions, 

 all the results were good, the only failure being in the attempt to 

 photograph the spectrum of the corona. — On the solar eclipse 

 of May 28, by MM. Meslin, Bourget and Lebeuf. Results of 

 observations made at Elche. The photograph of the spectrum 

 of the corona, obtained with a Rowland concave grating, shows 

 circles corresponding to the lines H, K and G. — Observations of 

 the eclipse of the sun of May 28, by M. de La Baume Pluvinel. 

 Nine photographs of the corona were taken, but the instrument 

 set apart for the special study of the coronal line gave no 

 result. — On the proportion of polarised light in the solar corona, 

 by M. J. J. Landerer. The proportion found was 0*52. — The 

 eclipse of the sun of May 28 observed at Besan9on, by M. 

 Gruey. — The partial eclipse of the sun of May 28, at the Ob- 

 servatory of Lyons, by M. Ch. Andre. The scheme of opera- 

 tions included the comparison of the time of direct observation of 

 contact with that made by projection upon a white screen, and the 

 examination of the dark line noted in the eclipse of 1882. — 

 The solar eclipse of May 28, observed from a balloon, by Mdlle. 

 D. Klumpke.— On the theory of the moon, by M. H. Andoyer. 

 — On the congruences of circles and spheres which are multi- 

 cyclic, byM. C. Guichard.— On divergent series, a correction.of 

 an earlier note, by M. Le Roy,— On the decomposition of con- 

 tinued finite groups, by M. Edmond Maillet. — On the integra- 

 tion of the equation Am =/«<, by M. J, W. Lindeberg.— On the 

 electrical state of a Hertz resonator in activity, by M. Albert 

 Turpain. — Researches on the existence of a magnetic field pro- 

 duced by the movement of an electrified body, by M. V. 

 Cremieu, According to Maxwell, a charged electrified body in 

 motion should produce magnetic effects, the magnitude of which 

 can be calculated from the charge and velocity of the moving 

 body, and experiments by Rowland in 1876, and Rowland and 

 Hutchinson in 1889, gave results in agreement with Maxwell's 

 views, Lippmann, applying the principle of the conservation 

 of energy to Rowland's experiment, shows that magnetic 

 variations ought to produce a movement in electrified bodies 

 situated within the field, but experiments by the author 

 would appear to show that such an effect is not produced. A 

 repetition of Rowland's original experiments, under conditions 

 more favourable to accuracy, also leads the author to conclude 

 that the motion of an electrified body produces no magnetic 

 effect.— Measurement of the quantity of electricity and of 



