56o 



SCIENTIFIC NEVS^S. 



[June 15, 18 



company has lately been formed there, with a capital of 

 about _;^8,ooo, called the Campania Anonima Explora- 

 dera de las Hucas del Inca, with the object of searching 

 for antiquities and valuables in the old Inca burial- 

 grounds in the district of Cuzco, a concession having 

 been granted to the company by the Government for 

 this purpose. The Consul says there is no doubt that 

 many valuable curiosities, and probably deposits of gold 

 and silver, exist in these ancient tombs, but it remains 

 to be seen whether they will pay the cost and trouble of 

 finding. 



The Proposed German South Pole Expedition. — 

 Mr. Henry Villard has addressed a letter, dated the 4th 

 inst., from Karlsbad, to the National Zeitung, in which he 

 ascribes the merit of having planned a German South 

 Pole Expedition to his fellow countryman, Mr. Neumayer, 

 director of the Marine Observatory at Hamburg. Mr. 

 Villard states that he offered to assist Mr. Neumayer in 

 his project, and that in the efforts he has made in the 

 matter he has met with a cordial response from all parts 

 of Germany. For the present, the writer adds, he is 

 only dealing with a mere project, but should the affair 

 end in the expedition being organised, the conducting of 

 it should be entrusted to the originator of the scheme, 

 Mr. Neumayer, who, as a man of science and a practical 

 seaman, is so eminently fitted for the task. 



Darkening a Lecture-room. — The lecture-room in the 

 physical laboratory at Cornell University is provided 

 with a novel means of darkening it, for the purpose of 

 projecting views on a screen, or for any experiment re- 

 quiring a dark room. The shutters to the windows are 

 suspended on cords which pass over pulleys, and are 

 joined to a single weight in the basement sufficient 

 to balance all the shutters. A long cylinder situated 

 under the weight is connected with the water 

 supply, and the piston rod raises the weight whenever 

 the water is admitted into the cylinder; the falling of the 

 weight closes the window shutters. This apparatus is 

 managed by a small lever at the reading stand at the 

 desk on the platform, so that the lecturer can, without 

 any unusual effort, either lighten or darken the room 

 according to the immediate needs of his lecture. 



The Ladies' Conversazione at the Royal Society. — 

 The second annual conversazione was held in the room 

 of the Royal Society on June 6th, and in response to the 

 invitation of the President and Council a brilliant and 

 distinguished company assembled. Many of the objects 

 shown have been already described in our account of the 

 first meeting (see page 470). In addition there was a 

 fine display of rare game birds from Central Asia, 

 exhibited by Mr. Henry Seebohm ; they were mostly of 

 the pheasant, grouse, and partridge class. Sir Frederick 

 Bramwell sent an ingenious revolving apparatus designed 

 to show at a glance the varying effect of colour produced 

 by combining different proportions of other colours. Mr. 

 Crookes exhibited specimens of auriferous quartz, 

 auriferous blende, and other gold-bearing minerals, from 

 Mr. Pritchard Morgan's mine near Dolgelly, as well as 

 an ingot weighing i cwt. 33 lbs. Mr. Burns showed 

 various kinds of ants, living and moving in their beau- 

 tifully constructed nests. In one cell was a queen, 

 with her servants ministering to her wants; in another 

 were aphides, or the ant-cows, with thejr keepers. 



One nest contained a party of workers busily employed 

 in building up an intruding queen, which Mr. Burns had 

 placed among them in the morning. One ant shown 

 threatens, according to Sir J. Lubbock, to extinguish all 

 other British species. Some of Mrs. Watts Hughes's 

 voice figures — i.e., figures and photographs of figures 

 produced by the voice acting upon an elastic membrane 

 used as a vibrating disc by placing on it either liquid, 

 paste, or powder, were very beautiful. Some of the 

 figures are strikingly like those of natural flowers, ferns, 

 trees, etc. The only fresh-water medusa known — a 

 jelly fish found in the Victoria Regia tank in the Botanic 

 Gardens some years ago, and which has appeared every 

 year since — was shown by Professor Ray Lankester, and 

 its lively gambols attracted many admirers. In the 

 library Mr. Walter Gardner exhibited a great number of 

 slides showing the vast variety of methods whereby 

 plants are enabled to maintain their place and spread 

 themselves abroad in the struggle for existence. 



Phosphorescence and Ozone. — From a scientific 

 point of view Professor Dewar's admirable lecture at 

 the Royal Institution, last Friday evening, was an agree- 

 able change from some of those given during the session 

 which has just been brought to a close. For more than 

 a year he and Professor Liveing have been seeking the 

 cause of the phosphorescent light produced in a vacuum 

 when an electric discharge passes through it, and the 

 chief object of the lecture was to show and explain a 

 series of experiments by which it can be proved that the 

 phenomenon is due to the presence of ozone. We are 

 all familiar with the beautiful colour effects produced by 

 passing an electric current through Giesler and other 

 well-known vacuum tubes, and Professor Dewar showed 

 that these effects are due to the phosphorescence of 

 gases remaining inside the tubes, and not to any phos- 

 phorescence of the glass. This he proved in the 

 following manner: — He exhausted a glass cylinder 

 about three feet long and about six inches in diameter, 

 and on passing a strong electric current through the 

 cylinder no luminous effect vi'as produced until he intro- 

 duced a jet of air. A thin luminous beam was then 

 visible along the axis of the cylinder, and it was remark- 

 able that at no time was there any light near ihe sides of 

 the cylinder. It was always confined to the middle. On 

 admitting hydrogen into the cylinder the luminous beam 

 was completely destroyed, and.pn turning off the hydro- 

 gen and again admitting air there was the characteristic 

 stre as before. When carbonic acid gas was intro- 

 duced the luminous beam became shorter but fairly 

 bright, and the lecturer explained that this effect was 

 doubtless caused by the production of ozone on some of 

 the carbonic acid being decomposed. When nitrous 

 oxide was tried the beam was brighter than in any of 

 the other experiment-, the light being strong enough to 

 read by in a dark room. Then to manifest the presence 

 of ozone. Professor Dewar placed a piece of starch 

 paper on a glass inside the cylinder, and on repeating 

 the experiment with air, in a few seconds a patch of 

 dark blue about one inch in diameter was formed about 

 the middle of the paper. This was due to the well- 

 known reaction of ozone on the iodide of potassium, the 

 iodine being liberated and a blue mark being left on the 

 starch paper. We hope shortly to give a report of this 

 interesting lecture, and we commend its perusal to all 

 who care to follow these important investigations. 



