June 20, 1901] 



NA TURE 



tion was established with Crookhaven by the Lake Champlain, 

 and mimerous service and private telegrams were despatched 

 notifying the steamer's safe arrival off Ireland. The next 

 station communicated with was Rosslare when forty-five miles 

 distant. For more than five hours there was a continuous 

 stream of messages, upwards of fifty being sent. Communica- 

 tion was next established with Holyhead, greetings being 

 interchanged at a distance of 33^ miles. When 37f miles from 

 Liverpool a message was received from the owners and orders 

 were despatched instructing the captain to disembark passengers 

 at the Princes' landing stage. 



A SERIES of line radiographs obtained by Dr. G. H. Rodman, 

 of East Sheen, has been sent to us by Messrs. Cox and Co. ; 

 and as we admire the minute details shown by them, we 

 appreciate the remarkable advances made in Rontgen ray 

 photography since the first pictures were obtained six years ago. 



fc,;-.%J« 



Four years ago a series of radiographs of all the British batrach- 

 ians and reptiles was prepared by Messrs. Green and Gardiner 

 and published. The application of Rontgen rays to biological 

 study was well exemplified by these pictures, and also by radio- 

 graphs of molluscs obtained later by the same observers, one 

 of an entire Nautilus and another of an entire Chiton being 

 particularly memorable. The uses of radiography to the study 

 of the shells of the MoUusca are, however, not so well known 

 as they deserve to be, and we are glad to direct attention to 

 the accompanying pictures obtained by Dr. Rodman. The 

 correct systematic position of many forms depends on the 

 presence or absence of certain plaits, or folds, or tooth-like pro- 

 jections, either on the central shelly pillar (columella) or on 

 the inner sides of the outer wall of the shell. These are fre- 

 quently so situated as to be invisible through the aperture, and 

 when only a .single specimen may be available, which it is un- 

 desirable to sacrifice in the cause of science, the utility of radio- 



NO. 165 1, VOL. 64] 



graphy in this connection at once becomes apparent. The 

 evidence of the accidental inclusion of a smaller shell (it 

 is too large for an embryo) in No. 7 is noteworthy. Radio- 

 graphy may also be able to determine the mineral condition of 

 the shell, whether the carbonate of lime in its substance takes 

 the form of calcite or arragonite, or of the one in the yoimg 

 and the other in the older shell, as would almost seem to be 

 the case in No. 7. On this point, however, further research 

 is necessary. In the case of the recent Nautilus shell, the 

 Rontgen process shows the details of every septum and the 

 siphuncle with great clearness, as may be seen by reference to 

 plate XV. of vol. xi. of the Proceedings of the Malacological 

 Society of London. For the benefit of those who may wish 

 to emulate Dr. Rodman, we may add that the exposure em- 

 ployed by him was 80 seconds at a distance of 1 1 inches on 

 an Imperial Special Rapid plate, using a Cox lo-inch spark coil 

 and their " Record " focus tube. This is the tube which has 

 just been awarded the gold medal given by the president of the 

 Rontgen Society, Dr. John Macintyre. 



We have received from the president of the Internationa. 

 Aeronautical Committee a preliminary account of the, balloon 

 ascents on May 14. Eighteen ascents took place, including 

 manned and unmanned balloons, of which six were at Berlin, 

 four at Strassburg and three at Vienna. Two of the unmanned 

 balloons have not yet been found. The highest altitudes were 

 reached by the French balloons. One of these ascents, made 

 from Chalais-Meudon, was particularly interesting : at starting 

 the temperature was I5°"S C, zero was recorded at 3661 m., 

 -50° at 9640 m., and the lowest temperature, -55°'8, at 

 11,025 ™- ; but an inversion of temperature afterwards oc- 

 curred, and on reaching the greatest altitude, 15,414 m., the 

 thermometer had risen to -32" '2. Two balloons were sent up 

 from Trappes (near Paris): one at 2h. 30m. a.m., which re- 

 corded 0° at 2740 m. and -64° at 11,400 m. ; the other, at 

 Sh. a.m., recorded zero at 2900 m. and -60° at 11,200 m. 

 On this occasion no balloon was sent up by this country. 



The new standard pentane ten-candle-power lamp and the 

 new form of photometer, prescribed for use in the official gas 

 testing-stations in London, were described by Prof. Frank Clowes 

 at a meeting of the Incorporated Gas Institute on Wednesday, 

 June 12. The source of light in the new lamp is the flame 

 produced by burning, under suitable and definitely prescribed 

 conditions, a stream of carburetted air. The carburetting liquid 

 is the light petroleum known under the chemical name of 

 pentane. The liquid pentane evaporates rapidly at ordinary 

 atmospheric temperatures, and the vapour which it produces is 

 rather more than two and a half times as heavy as atmospheric 

 air. As the name of the lamp implies, its flame has been shown 

 to give under prescribed conditions a constant illumination equal 

 to that furnished by ten standard candles. The new photo- 

 meter differs in its arrangement from the bar-photometers which 

 were previously in use in the fact that the flames under com- 

 parison are upon one side of the translucent screen, whereas in 

 the old forms the burners were placed on opposite sides of the 

 illuminated screen. But another essential difference from the 

 older forms of photometer, which provided for one fixed and 

 one travelling source of light, is that in the new photometer 

 both sources of light are fixed in position at accurately measured 

 distances from the observing screen. The equating of the 

 illumination of the screen is brought about by adjusting the 

 supply of the gas which is being tested to the Sugg's London 

 argand-burner. The new photometer and standard lamp have 

 now been in use for some time in the fixed testing-stations and 

 in different buildings in the area of the county of London. The 

 gas-examiners who have constantly employed the new apparatus 

 express a decided preference for it as compared with the bar- 



