278 



NA TURE 



\jfan. 17, 1884 



that body presented itself. Whatever chloropliyll may be from 

 a physiological point of view, for the chemist it is simply an 

 organic colouring matter. The colouring matters occurring 

 naturally in the organs of plants and animals are of several kinds. 

 The greater number Ijelong to the class of so-called glucoside^, 

 i.e. bodies which b. decomposition with acids or ferments yield 

 some kind of gUlco^e or sugar as one of the products. The 

 author was led to suspect that chlorophyll might turn out to be 

 a "lucoside, its general properties being such as characterise that 

 class of compounds. To prove this by direct experiment was 

 almost impossible, on account of the difficulty in preparing 

 chlorophyll in a state of purity ; but the authorj describes some 

 exjieriments made with solutions of chlorophyll, which tend to 

 show that when decomposed with acids it does behave as a 

 ghicoside, splitiing up into glucose and other bodies, the phyllo- 

 cyanin and phylloxanthin of Fremy being] products that are 

 formed at the same time. 



Mathematical Society, January to. — S. Roberts, F.R.S., 

 vice-president, in the chair. — -Messrs. U. Brockelhank and 

 A>utosh Mukhopadhyay were elected members, and Messrs. 

 Fortey and Heppel admitted into the Society. — The Chairman 

 spoke upon the late Mr. C. W. Merrifield's mathematical work 

 and upon his services to the Society, and concluded his remarks 

 by reading the words of a vote of condolence with the family of 

 tlie deceased which the Council had requested the President to 

 communicate to them. — Mr. A. Buchheim stated an extension of 

 Pascal's theorem to space of three dimensions, and communicated 

 a paper on the theory of screws in elliptic space. His special 

 object was to shovi' that Grassmann's " Ausdehnungslehre " sup- 

 plies all the necessary materials for a calculus of screws in elliptic 

 space, and that Clifford was apparently led to construct his 

 theory of biquaternions by the want of such a calculus. — Mr. 

 H. Fortey read a paper on contacts and isolations, a problem in 

 permutations. — Mr. Tucker presented a paper by Prof. H. Lamb 

 on the induction of electric currents in cylindrical and spherical 

 conductors, and spoke on a group of circles which are connected 

 with the "triplicate-ratio" circle. 



Edinburgh 

 Royal Physical Society, December 19, 1S83. — Dr. R. H. 

 Traquair, F.R.S., president, in the chair. — The following office- 

 bearers were elected for the year 1883-84, viz. Presidents, 

 Dr. R. H. Traquair, F.R.S., B. N. Peach, F.R.S.E., 

 F.G.S., r- A. Harvie-Brown, F.R.S.E., F.Z.S. ; Secretary, 

 Robert Gray, V.P.R.S.E. ; Assistant Secretary, John Gibson; 

 Treasurer, Charles Prentice, C.A., F.R.S.E. ; Librarian, 

 J. T. Gray, M.A. — The following papers were read, 

 'viz. : — Notes on the genus Gyracanthus, by Dr. H. Traquair, 

 F. R.S. — On a specimen of Pecopteris in circinate vernation 

 v^ ith remarks on the genera Spiropteris and Rhizomopteris of 

 Schimper, by Robert Kidston, F.G.S. — On a new species of 

 Schutzia from the calciferous sandstones of Scotland, by R. 

 Kidston, F.G.S. —On the structure of Sarcodictyon, by Prof. 

 W. A. Herdman, F.R.S.E. — Notes on the islands of Sula 

 Sgeir or North Barra and North Rona, with a list of the birds 

 inhabiting them, by Mr. John Swinburne. Specimens of eggs 

 from the islands were also exhibited. — Mr. J. A. Harvie Brown, 

 F.Z.S. , exhibited, with remarks, a specimen of the Little Gull 

 (Lanis minuhts), shot in the island of North Uist.— Mr. Hoyle 

 exhibited, with remarks, a skeleton of the extinct Moa (Vinoriiis 

 didiformis). — Dr. Traquair exhibited a specimen of the Osprey 

 (Paiidion haliaetus), shot in Midlothian — Prof. Arch. Geikie, 



F. R. S., was elected an honorary Fellow of the Society. 



Mathematical Society, January 11. — Mr. Thomas Muir, 

 F. K.S.E., president, in the chair. —Prof. Chrystal delivered an 

 address on surfaces of the second order, in which he advocated 

 strongly the study of the properties of these surfaces from the 

 surfaces themselves. The address was illustrated by a large 

 number of beautiful models in wood, plaster, cardboard, and 

 thread. — Prof. Tait communicated an analytical note, and one 

 or two geometrical problems were discussed. 



Dublin 

 Royal Society, December 17, 1883. — Rev Dr. S. Haughton, 

 F.R.S., in the chair — On the Ringhals or Cape Cobra, by M. 



G. R. O'Reilly. The author briefly describes some of the 

 habits of this snake [SiTpedon lutmacliates), called " ipimpi " by 

 tlie Kafirs. He is peculiarly subject to fear, but, when com- 

 pelled, fights savagely. Raising one-third of his length perpen- 



dicularly, and with expanded hood, he advances, dashing his 

 head repeatedly to the ground and hissing furiously. Sh luld he 

 come close enough, he strikes repeatedly, not open-mouihed, 

 but only with the point of the fangs that protrude lightly 

 downwards over the lower lip. But little poison is intrr, luced 

 into the superficial wound produced in this way, and such wounds 

 are not nearly so often fatal as those produced by the puff-adder. 

 There is, however, a time when the Ringhals is much more to 

 be dreaded. When driven to an extremity, he sometimes sub- 

 sides into a kind of swoon, and lies as if dead with his mouth 

 somewhat gaping, but woe to the man who should curiously ven- 

 ture his finger therein ; it would be instantly locked as in a vice, 

 the fangs would be buried in the flesh, and the poison would 

 flow unceasingly. He will not let go, but, like a tiuUdog, will 

 allow himself to bs beaten to death rather than relinquish his 

 hold. When he finds fatigue coming on, he exerts himself to 

 hold the faster, and each new exertion causes the deadly venom 

 to flow more and more. By degrees fatigue overcomes him, and 

 incli by inch, from the tail upwards, his rausclei lose their 

 rigidity, till at last after perhaps a quarter of an hour, finding him- 

 self unable to hold on any longer, he lets go. Then if again 

 attacked he fights anew, apoarently as fresh as ever ; but if 

 allowed a little peace he will lie still a few moments, and then 

 calmly glide away to feast again on the frogs in the sedges, or 

 sun himself once more by the heated rocks on the hillside. — 

 On more convenient equivalents for converting British into 

 metrical measures than those hitherto in use, by G. Johnstone 

 Stoney, D.Sc, F.R.S. Capt. Clarke's determination of the 

 length of the British yard in metrical measure, made at South- 

 ampton in i865 for the Ordnance Survey (see Philoiophicil 

 Transactions for 1867), differs by a small amount from that 

 which had previously been made by Capt. Kater, and it is note- 

 worthy that the iftuall difference between these excessively care- 

 ful determinatio s is greater than the difference between Capt. 

 Clarke's determination and the very simple equivalent. 



The yard = 9I4'4 millimetres ; 

 so that the outstanding error which will be incurred if this very 

 convenient number is a^lopted is of an amount which is inap- 

 preciable in ordinary good scientific work. It is less than the 

 expansion produced in iron standards of length by one degree of 

 temperature. Again, the pound avoirdupois differs, according 

 to Prof. Miller's determination (which is the mo;t elaborate we 

 possess), from the simple equivalent. 



The pound = 453 '6 grammes, 

 by only one-quarter of a grain avoirdupois in a kilogramme. 

 This is about 1/70 of the correction which would have to be 

 made in weighing water in order to reduce its apparent weight 

 to its weight in vacuo, and is of small account even in carefully 

 conducted scientific work. The value of the gall m, which fol- 

 lows from Capt. Clarke's determination of the metre, is 

 I '000027 times that adopted in Dowding's Metrical Tables, and 

 differs from the simple equivalent, 



The gallon = 4544 cubic centimetres, 

 by an amount which is less than a cubic centimetre in ten litres, 

 an error which is inappreciable ; measures of capacity )iot 

 admitting of being compared so closely as weights and measures 

 of length. Hence we may take as our fundamental units — 



The yard = 9i4'4 millimetres, 

 with an error of less than a fifth-metret ' in the metre, on the 

 authority of Capt. Clarke ; 



The pound = 453"6 grammes, 

 with an error of one-quarter of a grain avoirdupois in a 

 kilogramme, on the authority of Prof. Miller ; 



The gallon = 4544 cubic centimetres, 

 with an error of less than one cubic centimetre in ten litres, on 

 the authority of the best previous determinations corrected by 

 Capt. Clarke's. It is a truly remarkable circumstance that the 

 first of these numbers happens to be divisible by 3- and 2^, the 

 second by 2' and 7, and the third by l^. Divisors more con- 

 venient could hardly have been chosen for dealing with the 

 disorderly way in which Briti.sh measures are subdivided. They 

 furnish the following tables, which may be safely re- 

 commended : — 



' By metrets are to be understood decimal subdivisions of the metre. The 

 fifth-metret is the fifth of these, or the hundred-thousandth of a metre. It 

 is about the diameter of one of the red disks in human blood. 



