210 



sciujsrcu. 



[Vol. IX., ^'o. 213 



higher than in either American or German tobacco, 

 indicating that the plant had been much ' forced ; ' 

 and it contained much more lime than usual in 

 proportion to the potash and soda, as well as a 

 high percentage of chlorine. Moreover, water 

 extracted one-third more of soluble matter from 

 English than from American tobacco. 



It may be worth noting that this society has 

 now nearly three thousand members, that its jour- 

 nal is entering on its sixth volume (published 

 monthly under the direction of a committee), and 

 that its aims are perfectly distinct from the Chem- 

 ical society, which deals with pure science, and 

 from the Institute of chemistry, which is mainly 

 an association, for professional and self-protective 

 purposes, of analytical chemists, 



A paper on ' Telephonic investigations,' by Prof. 

 S. P. Thompson, is giving rise to three nights 

 discussion at the Society of telegraph engineers 

 and electricians, of which the veteran Sir Charles 

 Bright is now president. The paper, which is 

 well worthy of attentive study, contained an al- 

 most exhaustive classification of telephonic 

 transmitters, receivers, and transformers, — an 

 account of the author's numerous researches there- 

 upon, and especially of his ' valve ' telephone, — 

 and an elaborate discussion of the effect of heat 

 in microphonic contacts. The author concluded 

 with the following sentences, upon which the 

 discussion mainly turnei : '' In conclusion, I would 

 reiterate my conviction that the success of long- 

 range telephony depends upon the possibility of 

 devising instruments which, on the one hand, can 

 be used with higher battery power to transmit 

 stronger currents, and which, on the other hand, 

 will be adapted to receive these currents by means 

 of apparatus which, though not necessarily more 

 sensitive to small currents than the present re- 

 ceivers, will have a higher electrical and mechani- 

 cal efficiency. And I am convinced that the path 

 of progress lies very near the road already travelled 

 by those who have perfected the existing machine- 

 ry for the electric transmission of power." 



The direct opposite of this was very stoutly 

 maintained by Mr. Preece, head electrician of the 

 post-office telegraphs, who argued that both on 

 theoretical grounds, — viz., that, in Sir W. Thom- 

 son's law, the value of a in the equation 



a= GKrP 

 was independent both of current and of 

 electro-motive force, — and also as the result of 

 practical experiments, a great number of which 

 were quoted, long-distance telephony was a ques- 

 tion, not of instruments, but of line. 



At the annual meeting of the Physical society 

 of London, held this afternoon. Prof. Balfour 

 Stewart was re-elected president, and Dr. E. At- 



kinson, who for many years has been treasurer, 

 was elected a vice-president, while Prof. A. W. 

 Riicker (the recently appointed successor to the 

 late Professor Guthrie at the Science schools. 

 South Kensington) was appointed treasurer. The 

 society adopted an alteration of its rules, whereby 

 membership of a foreign or colonial scientific 

 society shall in future be held equivalent to the 

 personal knowledge, on the part of members of the 

 society, of candidates for its membership, W. 

 London, Feb. 12. 



GEOGRAPHICAL NOTES. 

 Africa. 



The latest letter of Dr. O. Lenz is dated Decem- 

 ber, 1886. On June 30 he left Kasonge, which 

 was being ravaged by small-pox. After he had 

 left the village the disease broke out among his 

 caravan, and among those who died of it were his 

 own and Bohndorf's servants. On the 7th of 

 August he reached the Tanganyika, where he met 

 with the English missionaries. He crossed the 

 lake to Ujiji, whence he wished to go north. 

 However, on account of the war between the Arabs 

 and northern tribes, he was unable to continue his * 

 journey, and was obliged to proceed towards the 

 east coast. He did not follow the well-knovrn 

 route from Ujiji to Bagomoyo, but chose the 

 Zambezi route. He crossed the land between the 

 Tanganyika and Nyassa, went by boat over Lake 

 Nyassa and down the Shire and Zambezi. Having 

 reached Kwilimane at the mouth of this river, he 

 embarked for Zanzibar. His arrival there Avas 

 announced a short time ago. 



Le mouvement geograpMque of Feb. 15 contains 

 an interesting sketch-map of the district north of 

 the Kongo by A. J. Wauters, showing the present 

 state of our knowledge of the hydrography of 

 that country according to the explorations of 

 Junker, Grenfell, Lupton Bey, and Flegel. The 

 Welle-Makua has been copied from a sketch fur- 

 nished by Dr. Schweinfurth, and shows the im- 

 portant discoveries of Dr. Junker. 



Stanley has left Zanzibar for the Kongo. At 

 the same time the famous Arabian trader Tippo- 

 Tip started for Stanley Falls, and has promised to 

 support Stanley's expedition. 



The January number of the Bulletin of the 

 Paris geographical society contains an accurate 

 map of the Ogowe in West Africa by Lieutenant 

 Mizon, and of his return journey to the coast. 

 In the paper which accompanies the maps, Mizon 

 describes the methods of observation, and gives 

 the positions of some of the more important 

 points. The maps are on the scale of about one 

 kilometre to an inch, and contain a great deal of 

 topographical and orographical detail. 



