NA TURE 



[May i, 1884 



c T NI 1 EHSIT1 ' AND EDI 'CA TIOA'AL 

 INTELLIGENCE 



Cambridge. — The following courses of lectures are being 

 delivered this term : — 



Mathematics — Prof. Stokes, Optics ; Prof. Darwin, I heory 

 of Potential and Attractions ; Trinity College, Mr. Glaisher, 

 Theory of Errors, Mr. Ball, Higher Solid Geometry, Mr. 1. |. 

 Thomson, Dynamics of a Rigid Body, Mr, Row,, Highei 

 Integral Calculus and Abel's Theorem, Mr. Forsyth. Thermo- 

 dynamics ; St. John's College, Dr. Besant, Analysis, for Si hedules 

 II. and III., Mr. Pendlebury, Laplace's and Bessel's Functions, 

 Mr. Webb, Elementary Rigid Dynamics; Pembroke College, 

 Mr. Burnside, Hydrodynamics; Emmanuel College, Mr. Webb, 

 Elasticity. 



Physics — Trinity College, Mr. Trotter, Electricity and Mag- 

 netism, Mr. Glazebrook, Elementary Physics ; Cavendish 

 Laboratory, Mr. Shaw, Elementary Physics : St. John's College, 

 Mr. Hart, Elementary Electricity, Practical Physics. Cavendish 

 Laboratory ; Advanced Demonstrations in Light and Sound ; 

 and Elementary Demonstrations in 1 Iptics and Electricity. 



Chemistry — Prof. Liveing, Course of Examinations and Per- 

 sonal Instruction of those who have attended his general course 

 in the last two terms ; Mr. Main, General Course, including 

 Carbon Compounds ; Mr. Pattison Muir, Non-Metals, and Ele- 

 mentary Organic ; Mr. Sell, Elementary Chemistry ; Mr. Scott, 

 Gas Analysis ; Mr. Lewis, Catechetical Course. 



Practical Chemistry — Demonstrations for 1st M.B. by Mr. 

 Sell and Fenton ; Demonstrations in Qualitative Analysis (Sid- 

 ney College), Mr. Neville ; Practical Courses at St. John's and 

 Cains College Laboratories. 



Mineralogy — Prof. Lewis ; and two Courses of Elementary 

 Demonstrations. 



Mechanism — Prof. Stuart, Differential and Integral Calculus 

 for Engineering Students ; Mr. Lyon, Machine Construction and 

 Pleat ; Mr. Ames, Surveying and Levelling. 



Physiology— Elementary, Prof. Foster; Structure and Func- 

 tion of the Central Nervous System, Mr. Langley ; Advanced 

 Physiology of Respirations, Dr. Gaskell ; Preparation foi 2nd 

 M.B., Mr. Hill. 



Human Anatomy — Prof. Macalister, Anatomical Basis of 

 Anthropology, Advanced ; Demonstrations and Dissections. 



Elementary Biology, Mr. Sedgwick ; Morphology of the 

 Vertebrata, Mr. Sedgwick ; Mollusca and Tunicata, Mr. 

 Weldon ; Mammalia, Mr. Gadow. 



Botany — Prof. Babington, Structural and Systematic ; Morpho- 

 logy, chiefly Cryptogamic, advanced, Dr. Vines ; Demonstra- 

 tion Lectures on Physiology, Mr. F. Darwin ; Demonstrations 

 in Systematic Botany, Mr. Potter. 



Geology — Stratigraphy, Local, Prof. Hughes; General Course, 

 Carboniferous to Recent, Dr. R. D. Roberts ; Palaeontology, 

 Elementary, Mr. T. Roberts ; Microscopic Petrology, Mr. A. 

 Darker ; Climatology, Mr. E. Hill ; Metamorphism. Mr. 

 Marr; Field Lectures, Prof. Hughes. 



SOCIETIES AND ACADEMIES 

 London 

 Royal Meteorological Society, April 16.— -Mr. J. K. 

 Laughton, M.A., F.R.A.S., vice-president, in the chair. — J. Y. 

 Davidson and T. Wright were 'elected Fellows of the Society. 

 — The following papers were read : — On the origin and course 

 of the squall which capsized H.M.S. Eurydice, March 24, 1S78, 

 by the Hon. Ralph Abercomby, F.R.Met.Soc. It will be re- 

 membered that the Eurydice, which was a full-rigged corvette, 

 when parsing Ventnor in the Isle of Wight, running free 

 before a westerly wind, with all sails set. was struck by a sudden 

 squall from the north-west ; and before sail could be shortened 

 she went on her beam ends, and the lee ports being open, she 

 filled and foundered. The author has investigated the character 

 of the weather preceding and following the day in question, and 

 finds that the squall was one belonging to the class which is 

 associated with the trough of V-shaped depressions. The squall, 

 which originated in the north of England, swept across the Isle 

 of \\ ight at a rate of about thirty-eight miles an hour. The 

 i>n was of an uncommon class, in which the rain occurs 

 after the passage of the trough, ami not in front of it, as is 

 usually the case. The weather generally for March 24 was un- 

 usually complex, and of exceptional intensity, and for this reason 

 ome of the details of the changes cannot be explained. — Water- 



I their formation, by Capt. J. W. C. Martyr. — The 

 weather forecasts for October, November, and December, 1S83. 

 by C. E. Peek, M. A., F.R.Met.Soc. '1 his is a comparison of 

 the weather indicated in the forecasts of the Meteorological 

 Office with that actually experienced at Rousdon in Dorset. - 

 On certain effects which may have been produced in the atmo- 

 sphere byfloating particles of volcanic matter from the eruptions 

 of Krakatoa and Mount St. Augustin, by W. F. Stanley, 

 F.G.S. In this paper were given details of a microscopical 

 examination which had been made of some dust that fell, 

 to the thickness of about two inches, upon the deck of the bark 

 Arabella, in lat. 5" 37' S., long. 88° 58' E., at about 1000 miles 

 from Krakatoa. and supposed to be from the eruption of that 

 volcano. The dust under examination was contained upon a 

 single microscopic slide. For the convenience of discussi in of 

 the subject the visible forms were separated into eight different 

 kinds of particles : — (a) Small masses and single crystals of 

 mineral matter visible by polarised light only. These were 

 principally of augite and of certain felspars, (b) Very thin chips 

 and scalesoi theabove. (c) Very small masses of dense ordinary 

 pumice, (d) Fractured chips of the above with one thin edge. 

 \e) Light apparently overblown pumice in relatively larg^ thin 

 plates. (/) Fractured parts off, but of larger bubbles traversed 

 by seams upon which septa normal to the surface formerly 

 existed, (g) Fractured parts of?, but of larger plates, with a 

 thicker seam on one edge or on one corner only. (/;) Thin 

 glassy plates of e, formerly of relatively much larger size. These 

 are of equal thickness throughout, and generally with one hollow 

 surface. The particles a and /< form only about half to one per 

 cent, of the mass, the whole of the remainder being of the dif- 

 ferent forms of pumice described. The particles g and /:, as 

 being much the lightest in proportion to their extent of surface, 

 were most dwelt upon. These particles, which the author termed 

 bubble-plates, are of irregular, angular forms. They measure 

 under the microscope, in different directions, from about '5 to 

 ■05 mm. The thickness of the plates is fairly uniform, varying 

 between 'ooi and '002 mm. When there is a seam on one 

 edge, the plate is smaller, and thickens towards the seam. By 

 taking the interior part of a large mass of pumice and 

 breaking it up into fine dust, some similar forms may be dis- 

 covered. These plates being of quite transparent, volcanic 

 glass (obsidian), they are invisible under the microscope, by 

 direct light ; but being placed in a medium of higher refractive 

 power, .is Canada balsam, they become clearly defined under 

 oblique illumination, above a spot lens, with careful adjustment. 

 Mr. Stanley suggested that these thin plates were from over- 

 blown bubbles of volcanic glass such as forms the mass of 

 pumice ; that most probably they were projected from about the 

 centre of the volcanic chimney, where they could maintain a 

 melting temperature until they reached the higher atmosphere ; 

 under which conditions the internal steam in each separate 

 bubble would expand in volume through release of external 

 pressure until the bubbles burst in the very thin fragments 

 shown. These thin forms of bubble-plates, having great surface 

 in comparison with their very small masses, were such as were 

 eminently adapted to tloat in atmospheric currents to great 

 di-tances. As such particles would descend with their convex 

 sides downwards, they would also be especially adapted to reflect 

 the sun's rays, when the sun sank to the horizon, whereas when 

 the sun was at greater altitude his rays would pass through 

 them nearly unobstructed. It was therefore proposed that the 

 after-glow so often observed since the eruptions of Krakatoa and 

 Mount St. Augustin was possibly due to reflection from these 

 thin plates. 



Dublin 

 Royal Society, March 17. — Section of Physical and Experi- 

 mental Science. — Howard Grubb, M.E., F.R.S., in the chair. 

 — On the success of an instrument for completing the optical 

 adjustment of reflecting telescopes, by G. Johnstone Stoney, 

 M.A., D.Sc, F.R.S., vice-president of the Society. The 

 author had been astronomical assistant to the late Earl of Rosse, 

 and while in charge of his observatory became impressed with 

 the importance of increasing both the degree of accuracy and the 

 facility with which reflecting telescopes can be adjusted. At 

 the Cheltenham meeting of the British Association in 1857 he 

 described an instrument designed to attain these ends, but had 

 no opportunity of testing its performance till two years ago, 

 when a twelve-inch mirror came into his possession of exquisite 

 defining power, figured by the late Mr. Charles E. Burton. B. A., 

 F.R. A.S. This mirror is mounted as a Newtonian tel 



