April 4. 1901] 



NA TURE 



547 



of atmospheric changes. It is not in Germany alone that such 

 knowledge would be of advantage. There are occasions in 

 which the weather in any one or more of the districts of the 

 British Isles could be easily characterised by a single word of 

 one or more syllables, but to go a little further into detail and 

 make a forecast describing the weather of the ensuing twenty- 

 four hours in ten words, and no more, requires, on the part of the 

 recipient, some intelligent acquaintance at least with weather 

 telegraphese. It appears that in Germany the local authorities 

 have taken the matter up with the prospect, according to Dr. 

 Bornstein, of securing a more effective weather service than any 

 other country in Europe. 



The paper on combined trolley and conduit tramway systems, 

 read by Mr. A. N. Connett at the last meeting of the Institution 

 of Mechanical Engineers, is one of considerable interest and 

 importance. Of the four systems of electric tramways only the 

 conduit and the trolley can be considered to be commercially 

 practicable, since the surface contact system, though not want- 

 ing many and distinguished advocares, can hardly be said to be 

 properly out of the experimental stage, and the accumulator 

 system is still waiting for a thoroughly satisfactory traction cell. 

 The trolley and the conduit are both in wide use, especially in 

 America and on the Continent, and there are many lines at 

 work combining the two systems. The trolley is objected to ip 

 large towns on the ground of its ugliness, its potential danger 

 and the disadvantage involved in using the track rails as a return 

 conductor. The conduit, on the other hand, is too expensive 

 for country or suburban lines where the cheaper trolley is 

 admissible. We have, therefore, in the case of tramways running 

 into crowded towns from the outlying districts, a need for a com- 

 bined system ; this involves a special construction of the car to 

 enable a quick change to be made from the one system to the 

 other at the point of junction, and it is the problem thus raised 

 that Mr. Connett discusses. The paper also deals at some 

 length with the relative merits of side and centre slots for the 

 conduit system, and gives a comparative estimate of the costs of 

 installing conduit and trolley systems respectively ; it is to be 

 noted that the conduit is about twice as expensive as the trolley- 



AccoRDi.VG to a recent report the expectations of the con- 

 structors of the great Chicago Drainage Canal, which was made 

 for carrying away the sewage of the city, containing over a 

 million inhabitants,;have been realised. The idea of pouring the 

 sewage of a large city, amounting to 5o,cxx) cubic feet a minute* 

 into an open channel and allowing it to flow away without any 

 attempt at purification was both novel and startling. Now it 

 appears, after eight months' working, none of the actions 

 threatened by the towns bordering on the river below Chicago 

 have been commenced, and it is reported by competent authori- 

 ties that the water in the canal is free from objectionable fea- 

 tures. In fact, the water-way is used largely by pleasure boats 

 and the water taken by the manufactories situated on the banks. 

 It has also been found, on investigation by the Government Com- 

 mission, that so far no appreciable effect has been made in lower- 

 ing the water in Lake Michigan, a consequence that excited at 

 one time great fears on the part of the harbour authorities round 

 the coast. The immunity from the objectionable conditions 

 which prevail in the Manchester Ship Canal owing to sewage 

 being discharged into it is due to the large volume of clean 

 water that is always passing down the water-way from Lake 

 Michigan, a stream 22 feet deep and running at the rate of a 

 mile an hour being sufficient to neutralise the foul condition of 

 the 50,000 cubic feet of sewage sent into it every minute. 



The embryos of the New Zealand tuatera lizard recently 

 received in this country have afforded to Mr. H. S. Harrison 

 opportunities for studying the early dental developments of that 

 NO. 1640, VOL. 63 J 



remarkable reptile, the results of which are published in the 

 Quarterly Journal of Microscopical Science for March. The 

 outcome of these studies is to show that Sphenodon (or, as it is 

 often incorrectly called, Hatteria) in its early stages possesses 

 numerous sharp-pointed teeth very similar to those of many 

 ordinary lizards ; and as these are of irregular size at a certain 

 period, it is inferred that they represent several coalesced dental 

 series. On the completion of this alternating series a period of 

 repose occurs, after which a development of uniform teeth 

 takes place. By a secondary formation of bone round their 

 bases, these teeth acquire what may be called false sockets. 

 Subsequently the sides of the jaws are invested with a highly 

 calcified layer of bone, which, when the teeth become worn 

 down and the sides of the jaws exposed, assists the edges of the 

 latter in the assumption of dental functions in the adult. 



To those interested in domesticated animals, whether from 

 the point of view of the breeder or of the study of variation 

 under human influence, the spring number of Bibby i Quarterly 

 should prove very welcome, as it contains an unusually large 

 number of reproductions of photographs of prize and other 

 cattle, sheep, horses, &c. As marking the changes introduced 

 by breeders, such photographs are of very considerable import- 

 ance, and their reproduction in a journal of this description 

 renders them accessible to all. A feature of the present number 

 is an article by Prof. J. C. Ewart on " Prepotency and Exclusive 

 Inheritance." The numerous photogravures in this article illus- 

 trate the predominating influence of one or other parents on their 

 offspring in many breeds of domesticated animals. In an article 

 on Boer farm life, attention cannot fail to be arrested by the 

 photogravures of an arum-field and of flocks of domesticated 

 ostriches. Arums, it appears, are grown as food both for pigs 

 and ostriches. 



Opportunity to study the geology and physical geography of 

 the basin of the Thames is afforded by the Saturday afternoon ex- 

 cursions |of the London Geological Field Class, which commence 

 on April 27. Visits have been arranged to places of geological 

 interest both north and south of London, and the excursions 

 provide exceptional facilities for examining some of the greater 

 movements which the south-east of England has experienced. 

 Particulars can be obtained from the honorary general secretary, 

 Mr. R. H. Bentley, 43, Gloucester Road, Brownswood Park, N. 



Referring to the periodic variations of glaciers, the remark 

 was made in our issue of March 7 (p. 444) that, in the Swiss 

 Alps " of fifty-seven glaciers observed in 1897, fifty were still 

 decreasing, five were stationary and twelve were increasing." 

 A correspondent points out that this would make sixty-seven 

 glaciers observed, and the author informs us that the difference 

 arose from a clerical error in copying the numbers from the 

 original memoir. The number thirty-nme should be substituted 

 for fifty, making the total number of glaciers observed to be 

 fifty-six instead of fifty-seven. 



The first place in the March number of La Geographie is 

 given to a review of Colonel Yates' book on Khurasan and 

 Sistan, by Prof. Vambery. M. Bonin continues his account of 

 a journey from Pekin to Russian Turkestan by Mongolia, Koko- 

 Nor, Lob-Nor and Dzoungaria. Papers on three expeditions 

 in the French Congo region are contributed by MM. Jobit, 

 Loefler and Huot, and Mr. J. W. Hodge reviews recent ethno- 

 graphic and archa;ological explorations in the United States, 



We have received a copy of the " Report of Progress of the 

 Survey of Tides and Currents in Canadian Waters " for the 

 year ending June 30, 1900, by Mr. W. Bell Dawson, engineer 

 in charge. Considerable advance has been made in the prepara- 

 tion of tide-tables, and a pamphlet issued during the year on 

 the currents in the Gulf of St. Lawrence has already beea 



