August 6, 1891] 



NATURE 



327 



which are neither purely mechanical nor chemical, Herr Hof 

 meister brings into analogy with those occurring in absorption 

 of gases by liquids, the reciprocal solution of liquids, adsorption 

 of gases on solid bodies, &c. 



'Yk^ Photographic News quotes the following from the Scientific 

 American, December 9, 1848 : — "New Electrical Light. — The 

 inventors of a new electrical light, exhibited at the Western 

 Literary Institution, Leicester Square, London, on its recent 

 reopening under the new auspices, expect, it is said, to apply it 

 generally to shop and street illumination, and they state that, 

 while th2 conveying will cost no more than gas, the expense of 

 illumination will be one-twelfth the price of the latter light. 

 The current of electricity, in passing through the two pieces of 

 charcoal which form the poles of the circuit, and are excluded 

 from all access of air, gives, in this case, it is said, an intense 

 and beautiful white light, with the effect of daylight, to a much 

 greater extent than the lime does, and having this advantage, 

 that it is sustained and continuous. If Messrs, Staite and 

 Petrie can thus produce a steady and sustained light they have 

 accomplished what has hitherto been the sole preventive to the 

 substitution of galvanism for gas. The Mechanics Magazine 

 states that this one light completely eclipsed ten gas lights and 

 an oxyhydrogen. The gas companies had better look out. 

 The dissatisfaction of the public with their mismanagement may 

 have begotten a rival destined to eclipse many more than merely 

 ten of their gas lights." 



With the view of certifying to the efficiency of teachers of 

 public elementary schools to give instruction in woodwork in 

 accordance with the provisions of the Code (1890), the City and 

 Guilds of London Institute is prepared to issue certificates to 

 qualified teachers of public elementary schools on the following 

 conditions : — The candidates will be required to give evidence 

 of having regularly attended during each of two sessions, a 

 course •f at least twenty practical wood-working lessons in a 

 school or class certified by, and under an instructor approved by, 

 the Institute. The candidates will further be required to pass 

 aa examination at the end of each year's course, to be conducted 

 by examiners appointed by the Institute, and to pay a fee of 

 five shillings for each examination. For the first year, candi- 

 dates who have attended an advanced course of instruction will 

 be exceptionally admitted to the second year's examination with- 

 out having passed the first, and will be eligible for the teacher's 

 certificate. The examination fee for such candidates will be ten 

 shillings. The written examination will include questions 

 founded on such subjects as the following : — Woods. — Places from 

 which some of the commoner woods are obtained. Their 

 characteristic properties and uses. The general structure of 

 cone-bearing and leafy timber trees. The meaning of seasoning 

 timber. Effects of shrinkage and warping. Identification of 

 specimens of wood. The questions will be limited to oak, ash, 

 elm, beech, mahogany, sycamore, basswood, white deal (spruce), 

 red pine (Scotch fir), yellow pine. 



Das Wetter for July reports a curious case of globular 

 lightning which occurred at Berga, near Schlieben, in Germany, 

 between 3 and 4 o'clock on the morning of July i. The 

 lightning entered the chimney and split into two parts, one 

 portion ran along the rafters of the roof, and the other entered 

 a bed-room occupied by a man with his wife and three children. 

 The man, who was up, on account of the violence of the storm, 

 saw the ball jump on to the bedstead, which it broke, and from 

 there it slowly travelled to the opposite side of the room, and 

 disappeared, with a loud crash, through the wall. None of the 

 occupants were injured, further than being deafened for a short 

 time. 



The additions to the Zoological Society's Gardens during the 

 past week include a Banded Ichneumon {Herpestes fasciatus) 1 

 NO. I 1 36, VOL. 44] 



from West Africa, presented by Dr. Arthur Williams ; a Black 

 Stork {Ciconia nigra), European, presented by Lord Lilford, 

 F. Z.S. ; two Nilotic Crocodiles {Crocodilus vulgaris) from 

 Africa, presented by Dr. Lester ; two Black Storks ( Cicofiia 

 nigra), European, two King Parrakeets {Aprosmictus scapu- 

 latus) from New South Wales, purchased ; a Laughing King- 

 fisher {Dacelo giganlea) from Australia, deposited. 



OUR ASTRONOMICAL COLUMN. 

 Researches on the Mean Density of the Earth. — 

 The Monthly Notices of the Royal Astronomical Society for June 

 contain a brief account by Prof. A. Cornu of the experiments 

 M. Bailie and himself have been making for some years to deter- 

 mine the mean density of the earth. The apparatus employed is 

 fundamentally the same as that used by Cavendish. It consists 

 of a horizontal aluminium rod, suspended by a torsion thread 

 4 metres long, carrying at each end a imll of copper, bismuth, 

 iron, or platinum, and at its centre a vertical mirror reflecting 

 the divisions on a millimetre-scale 5 metres away. Two globes 

 of mercury are used to produce the torsion couple. The dis- 

 placements of the scale-divisions are observed with a telescope, 

 and indicate the angular displacements of the rod. The chief 

 improvements which have been made upon the apparatus used 

 by Cavendish, Baily, and Reich, are as follows :— (i) The length 

 of rod connecting the suspended balls has been reduced to O'lJO 

 metre, i.e. to a quarter the length adopted by the above-named 

 observers. (2) The attracting masses have been reduced to ro kilo- 

 grammes. Cavendish used masses weighing more than 140 

 pounds. And the method of using fixed globes which can be 

 quickly filled with mercury has been advantageously substituted 

 for the movable lead weights. (3) The complete oscillation of 

 the balance arm is registered on a chronograph by observing and 

 recording the transits of the reflected scale divisions. (4) The 

 use of an annealed glass fibre to eliminate errors due to dis- 

 placements of the zero point. (5) The screening from variations 

 of electric potential by putting all parts of the apparatus in 

 metallic connection with the earth. (6) The copper case pro- 

 tecting the balance arm is a good conductor of heat, and of 

 sufficient thickness to eliminate the disturbances due to variations 

 in temperature. The authors hope soon to obtain an estimation 

 of the probable error of their measures, and to arrive at a definite 

 result for the constant they are determining. 



Parallax of P Urs.b Majoris. — Vol. xxxviii. of the 

 "Astronomical Observations of the University Observatory of 

 Konigsberg" contains the heliometer observations of P Ursae 

 Majoris (Arg.-Oeltzen 1 1677) made by Dr. lulius Franz, from 

 which he deduces the parallax o"-ioo2 ± o"'oo65, or approxi- 

 mately o""io ± o"*oi. 



THE PROGRESS OF MEDICINE. 



T^IIE Bournemouth meeting of the British Medical Association 

 •^ has been a great success, and a great deal of useful work 

 and discussion has been recorded. Among the addresses we 

 niay refer to the President's (Dr. J. R. Thomson), on the present 

 position of medical officers of health ; of Dr. Lauder Brunton, 

 on twenty-five years of medical progress ; of Dr. J. Chiene, on 

 rest as a therapeutic agent in surgery ; and others on lunacy 

 legislation, the uses and prospects of pathology, &c. 



We make the following extracts from Dr. Brunton's address, 

 which presents us with a most admirable and masterly analysis 

 of recent progress : — 



. . . Perhaps there is no period in the whole history of medicine 

 in which such rapid changes have taken place as in the last 

 five-and-twenty years. It is impossible to give anything like a 

 complete account of these in the brief space of one hour, and I 

 shall therefore restrict myself to a few of the more prominent 

 points, and especially those that have come directly under my 

 personal cognizance ; for, like the man who made one-half of 

 his fortune by attending to his own affairs and the other half by 

 leaving other people's alone, I may probably utilize the time at 

 my disposal best by speaking of what I know myself and leaving 

 other things out. 



Advances in Knowledge and Teaching due to Experimental 

 Method. — These changes have occurred both in the profession 



