September 30, 1897] 



NATURE 



523 



chains less well constructed, a greater loss has been found, the 

 friction lying generally between 2 and 5 per cent. ; the maximum 

 shown, even by an old chain which did not fit its sprocket 

 properly, was under 10 per cent. No bevel gears as yet con- 

 structed give as good results as these, and Prof Carpenter con- 

 cludes that with even the best bevel-geared bicycles the loss must 

 be four times as much as with the ordinary chain, and six times 

 .-IS much as with the best chain. Moreover, as has been pre- 

 viously pointed out, gear wheels to work well must be in very 

 accurate adjustment with each other, whilst with a chain no 

 such careful fitting is required. 



The current number oi'The Engineering Magazine contains 

 an instructive illustrated article, by Mr. Ridgely Hunt, on fifty 

 years of advance in marine engineering. The accompanying 

 diagram, reproduced from our contemporary, shows at a glance 

 the increase of tonnage and speed during the last half-century. 

 In this period iron and steel have supplanted wood, and, says 

 the author, " engines have advanced from simple to compound, 

 and then to triple-expansion ; so, too, have paddle-wheels been 

 discarded for single-propellers and for twin-propellers ; so, too, 

 have single rectangular boilers with one flue, been replaced by 

 several boilers, cylindrical, and with many tubes ; so, too, have 



».jt » LUCANIA 



jet condensers been transformed into surface condensers, and the 

 steam pressures have been raised from 10 to 100 and 200 pounds 

 to the square inch. The size of steamships has been multiplied 

 twenty-fold, and the horse-power forty-fold. The speeds of the 

 ships have been increased from 8 to 17 and 23 knots; and in 

 every other respect has there been a like extraordinary evolution." 

 How the conversions have been effected is briefly described in 

 Mr. Hunt's interesting paper. 



A VERY brilliant aurora observed on April 20 in lat. 47^° S. , by 

 Captain M. W. C. Hepworth, was briefly described in our notes on 

 June 24 (p. 183). Mr. T. F, Claxton, the director of the Royal 

 Alfred Observatory, Mauritius, sends us an account of magnetic 

 disturbances apparently connected with the aurora display. He 

 says that on the day of the aurora a rather large magnetic 

 disturbance was recorded at the observatory, '* From June 

 20<1. gh.-igh. the horizontal force decreased '01578 m.m.s. 

 units. From 2Ck1. I2^h.-i9h, the vertical force increased 

 00336 m.m.s. units, and the declination, from 2od. 9jh.-i3h., 

 decreased 9''2, and from I3h. to I9h. increased 7''0. The 

 most active period was from 2od. i7h.-2oh. The magnets 

 NO. 1457. VOL. 56] 



were quiet from 2 id. oh. -23d. loh. 1 6m., when a suddcD 

 decrease of horizontal force, vertical force, and declination 

 occurred to the extent of '00258, '00056 m.m.s. units, and I'-a 

 respectively. In horizontal force the decrease continued till 

 23d. 2ijh., and amounted to •01204 m.m.s. units, while the 

 disturbance in vertical force was very small." 



The report of the Central Meteorological Ofiice of France for 

 the year 1896, shows a large amount of work performed, and is 

 very creditable to the staff of that institution. One of the 

 principal services rendered consists in predicting the approach 

 of storms for one or two days in advance. Out of thirty-four 

 storms which reached the French shores, thirty-one, or 91 per 

 cent., were foretold. This satisfactory result is, to a considerable 

 extent, due to the fact that the great majority of these disturbances 

 cross the British Isles, notice of which is regularly telegraphed 

 to Paris by the Meteorological Council. The number of tele- 

 graphic reports received daily amounts to 167, some of which are 

 from America, and include observations received from the fast 

 trans-Atlantic steamers. In the department of climatology, 

 reports are received from 211 places, in addition to a very large 

 number of rainfall stations, and the results and discussions are 

 published in three large quarto volumes yearly. In addition, 

 monthly returns are received from about fifty foreign stations, 

 as well as a large number of ships' logs. Particular attention is 

 also paid to the collection of observations made at mountain 

 stations, as well as by means of balloons and kites. The 

 observation of clouds has formed a special feature during the 

 past year ; between July 1896 and April 1897, M. Teisserenc de 

 Bort has taken no less than 2500 photographs of clouds at his 

 observatory at Trappes, and by this means the heights of 750 

 have been determined. 



We have already had occasion to direct attention in our 

 columns to the ingenious experiments conducted by Messrs. 

 Nuttall and Thierfelder on the possibility of animal life being 

 carried on in the absence of bacteria in the digestive tract ; the 

 third memoir on this subject by these gentlemen has now 

 appeared in the Zeitschrift fiir physiohgische Chernie, Bd. xxiii., 

 1897. In their previous experiments guinea-pigs were selected 

 as subjects for experiment, but it not unnaturally occurred to the 

 authors that chickens would be more suitable, inasmuch as they 

 might remove some of the great difticulties which attend the 

 procuration of the former animals in an aseptic condition from 

 their birth. Accordingly, a few hours before the chicken was 

 due to be hatched some eggs were carefully washed outside with 

 corrosive sublimate and hydrochloric acid, to remove all ex- 

 ternal germ-life, and were then placed in the sterile apparatus 

 devised by the authors, and employed in their previous experi- 

 ments. But, despite the most careful manipulations, bacteria 

 obtained access to the apparatus and spoilt the observations. 

 There was only one conclusion to be drawn, which was that 

 ' the egg-shells of the hatched chickens were responsible for the 

 mischief. Accordingly careful examinations of eggs were made,, 

 with the result that in every instance bacteria were found on 

 the inside of the shell. The authors conclude that bacteria are 

 present in the oviduct before and during the formation of the 

 shell, and become .attached to the membrane of the shell. This 

 unlooked-for and, from the experimental point of view of the 

 investigators, unpropitious discovery has led to the abandon- 

 ment of chickens for the purpose of these observations, and the 

 authors do not announce any further intention of pursuing their 

 interesting researches. 



Cultivators in many regions of the globe will be interested 

 in what appears to have been a successful series of locust-de- 

 stroying experiments carried out in Natal, a report of which has 

 been published in that colony as a Government notice. From a 

 note in the Times, it appears that all attempts to suppress the 



