May 12, 1881] 



NATURE 



29 



tube A is narrowed in the middle, and its los\ er extremity ter- 

 minates in a naiTow tube about 33 inches long, and dipping into 

 a cylinder of mercury. Some boiled water was introduced into 

 A before the thermometer was attached, and a small quantity cf 

 water was placed in the copper flask. The air was then removed 

 by the Sprengel, the exhau>tion being facilitated by heating the 

 copper flask. The water in the glass tube was also heated, in 

 order to expel the dissolved air. When the exhaustion had been 

 completed, the cylinder of mercury was raised until the mercury 

 in the tube stood at the narrow part of A, and the cjlinder sur- 

 rounding the tube was filled with a freezhig mixture of ice and 

 salt, the copper flask being also placed in a similar mixture. 

 When the water in the glass tube was solidified, the freezing 

 mixture was removed from the cylinder, the latter lowered, and 

 the coluirn of mercury was depessed by lowering the cylinder 

 of mercury until the column stood .at the bottom of A. 



A small gas flame was employed to warm the part of the tube 

 containing the ice ; some of the ice at the lower part of the 

 solid plug melted and ran down to the surface of the mercury ; 

 the upper portion of the ice could not be fu ed in consequence of 

 the diminished pressure on its surface. When the ice was com- 

 pletely detached from the glass tube a fresh quantity of freezing 

 mixture was placed in the cylinder surrounding the lower part of A. 



The air of the room was at 15° C, and the thermometer in the 

 ice indicated - 8°. The tube A was now heated by a Bunsen 

 burner, and the temperature shown by the thermometer w,.s 



- 6°'5. A jet of steam from a test-tube with cork and narrow 

 tube was directed against the side of A until ihe ice became very 

 thin on one side of the thermometer bulb ; the temperature was 

 now - 1°. The freezing Uiixture surrounding the copper flask 

 was nearly exhausted ; it was therefore replaced by fresh ice and 

 salt, and the steam once more directed against the tube. The 

 thermometer now read - 5°'2. When a small part of the ther- 

 mometer bulb was free from ice the jet of steam v as stopped, and 

 a new freezing mixture placed round the flask, the thermometer 

 indicating — iP"]. When about one-third < f the bulb was 

 exposed the tube was heated by a Bunsen flame and the tem- 

 perature rose to -f 4°, and on allowing the tube to cool it fell to 



- 5°. Finally, when only a very narrow str'p of ite remained 

 attached to one side of the bulb, the tube w;s .strongly heated, 

 and the temperature rose to -f 12°, but on cooling it sank to 



- 2° 'a. 



The experiment was repeated en Jariuary 6, a jacket being 

 placed round the tube so that the heating by steam was more 

 regular than before. On first .'eparating the ice from the con- 

 taining tube the thermometer indicated - 8°. On heating with 

 a Bunsen it rose to - 6°. When the tube was cold the tem- 

 perature was - 14°. After passing a current of steam round 

 the tube for half an hour the temperature was - 11°. A fresh 

 freezing mixture was now used, and the steam again turned on ; 

 after twenty minutes a small portion of the thermometer bulb 

 became exposed, and two minutes later the temperature was 



- 9°, A fre.-.h freezing mixture was put round the flask, and 

 when the outside of the tube v as cold, the thermometer showed 

 a temperature of - 16°. Steam was again turned on for fifleen 

 minutes, when the temperature was - 12°. When the bulb 

 was half expcsed the steam jacket was removed, and the tube 

 heated by a Bunsen ; the temperature then ro^e to - i^'5. On 

 allowing it to cool it fell again to - 12°. When about three- 

 quarters of the bulb was free from ice the tube was again heated 

 by the gas flame, and the temperature rose to + 29°. The ice 

 then fell off, and although the heating was discontirued the 

 thermometer rose rapidly to 70°. 



These experiments, as far as they go, are therefore in accord- 

 ance with those of Mr. Hannay and Prof. Lothar Meyer, there 

 being no considerable rise of temperature until either the con- 

 den ation of the aqueous vapcur was too slow and the vacuum 

 thus deteriorated, or the thermometer bulb was partly uncovered, 

 and so exposed to direct radiation from the walls of the outside 

 tube. 



Two experiments were tried with mercuric chloride, but the 

 results were not satisfactory, in consequence of !he high melting 

 point of the solid. The temperature seemed to be above the 

 fusing point, but it was found that the mercury in the thermo- 

 meter stem had separated. Herbert McLeod 



Cooper's Hill, May 3 



Sound of the Aurora 



Under the above heading Mr. Ogle, in last week's Nature 

 (vol. xxiv. p. 5), gives an extract frt m the Visitors' Book at the 



.'Eggischorn Hotel describing certain electrical effects which were 

 experienced by Mr. and Mrs. Spence Watson, Mr. Sowerby, and 

 myself on July to, 1863. I would add one or two facts with 

 regard to our position and experiences. We reached the top of 

 the Jungfrau Joch at 10.5 a.m., and were met by a violent hail- 

 storm, H hich came rolling up from the northern side of the Col. 

 We at once started to return, 'and had been walking for two 

 hours doun the centre of the Aletsch glacier when the electrical 

 effects began to be felt ; we reached the Merjeltn See at 3. IS) 

 so that at the time of the occurrence we had reached the lower 

 part of the nirfc' which is farthest from surrounding mountain 

 tO|.s, where the gl.Tcier is widest. We were enveloped in cloud, 

 above which there were no doubt other cleuds charged with 

 electricity, and as they approached we were gradually being 

 charged more and more strongly by induction from the lower 

 cloud, and when the di- charges or thunder occm'red we w ere 

 suddenly relieved by an electric shock. Alind of b>ush dis- 

 charge of u'radually increasing intensity went on for some minn'es, 

 follow ed by a sudden shock, and this process of bringing us up 

 to the riu;ht state of excitement, to be relieved by a sudden shock, 

 was repeated over ar.d over again several times. 



The hissing sounds were first heard in the alpenstocks, and 

 gradually increased in loudness up to the sudden discharge. 

 There were clear indications that as condensers of electricity we 

 were not all of the same capacity. We were roped togeiher in 

 threes : in ore set of three I w.as in the middle, wiih a guide in 

 front and Mr. Sowerby behind. Whilst the charging was going 

 on I felt the pricking sensation at the waist on the side 

 where the cord was knotted, shewing that those who were more 

 influenced by electrical induction were charging the others 

 through the repe which acted as a conductor. Judging by his 

 actions, eur guide (a young and active n;an) was strcngly influ- 

 enced by ihe charge, whilst Mr. Sowerby, the most staid and 

 venerable of the party, was ceitainly influenced the lea-t. In 

 the othir set of three the elderly J. M. Caret of Chamouni was 

 least afltcted, wtertasMr. Watsi n, who was net the youngest of 

 the party, was the most \ ov erfully affected. These facts point 

 to a direct relation between the tcmperamei.t of the individual 

 and his capacity for being excited electrically or his inductive 

 capacity. 



I should add that Mr. Packe has had similar experiences, but 

 apparently to a less extent, in liis walks in the Pyrenees. 



W. Grylls Adams 



Wheatstone Laboratory, King's College, May 9 



Palaeolithic Man 



In my communication to Natijre, vol. xxiii. p. 604, I chiefly 

 restricted my notes to the higher gravels on the north side if the 

 Thames in and near London. \^ ith your pern:ission I will now 

 briefly refer to some of the implementiferous gravels south of 

 London, especially in Kent. 



The best known of these are to be seen between the Reculvers 

 and Heme B.ay, where a thin stratum of implementiferous gravel 

 caps the cliffs. Similar but deeper gravels, also bearing imple- 

 ments, occurs elsewhere inland, as at and near Chislet. At 

 Canterbury a great number of implements have been found, and 

 to these gravels and imj lements I would now direct attention. 

 As a rule the Reeulver instruments are sharp, unstained, and 

 unabraded (such as have been rolled in the : ea of course ex- 

 cepted) ; the Canterbury examples wliere the gravel is deep are 

 found at various depths, from 9 feet to 20 feet. 



Now there are two distinct classes of implements found in the 

 Canterbury pits, the levels being, according to Pr. Evan<;, about 

 80 feet or ico feet above the river : in one cla s the specimens are 

 well made and almost as sharp and un-tained as when first 

 turned from the maker's hands, in the other the impleu.ents are 

 much more rudely made, deeply stained all over of a dark ochreous 

 brown colour, and abraded in a high degree. These latter 

 implements come from distinct strata or deposits of ochreous 

 brown rolled stones that appear to have been brought from a 

 long distance. In my own collection of twenty-nine examples 

 from Canterbury one half are sharp and bright, the other half 

 greatly rolled and deep brown in colour. To my mind these 

 two cla«es of instruments represent two totally distirct periods 

 in the Paleolithic age immensely removed in time from each 

 other, the abraded examples being the oldest. A point of 

 importance to be ob^er\•ed in the deeply ochreous implements is 

 that many of them were slightly splintered or broken when they 

 w ere deposited in the Canterbury drift ; now these broken and 



