July 3, 19 13] 



NATURE 



461 



Towards the end of the memoir he makes a com- 

 parison with ninety-six stars of the same cluster, taken 

 by Rutherford during the years 1870-74 and measured 

 by Miss Young, and he finds that they agree within 

 very small limits, with the exception of one star. 

 Omitting this, and two others which were measured 

 only on one of his two plates, the differences Young 

 minus Messow were as follows : — 



U„ = o-ooos. 1) = +o"oi' 



A further investigation of the differences between 

 Young and Messow as regards proper motion leads 

 the latter to state that the two star clusters have not 

 altered their position in space. The memoir concludes 

 with a catalogue of the positions of the 649 stars for 

 1899-1900, together with their estimated and measured 

 magnitudes. 



Oxford University Observatory.— From the 

 thirty-eighth annual report of the Savilian professor 

 of astronomy we learn that the Cambridge ledgers 

 containing the corrections to the Cambridge meridian 

 observations from all the separate plates taken at 

 Oxford have now been completely revised and dis- 

 cussed for magnitude equation. It has been found 

 thai the observations of faint stars are affected by 

 considerable and rapidly changing errors, such as 

 Pnif. Arthur Searle found at Harvard. To enable 

 this work to be accomplished, the work on differential 

 star places had to be temporarily put aside. We are 

 further informed that two zones ( + 64° and +63°) 

 of the Vatican plates have been completely reduced 

 with the exception of one doubtful plate in zone 

 + 63 . This plate has since been repeated at Rome. 



THE THIRD INTERNATIONAL ROAD 

 CONGRESS. 

 r pHE Permanent International Association of Road 

 J- Congresses, which held its first meeting in 

 Paris five years ago, completed its third congress in 

 London on Saturday last. The attendance of home 

 and foreign members and visitors was far greater 

 than at either of the two previous meetings, and there 

 is no doubt that both in the quantity and quality of 

 the matters discussed, and the general interest taken 

 in the road inspections and in the road-making appa- 

 ratus shown at the exhibition, this congress showed 

 a marked advance on the two previous ones. 



Too much was attempted. Papers on nine impor- 

 tant questions had been invited, and the response 

 was such that more than 120 papers replying to the 

 questions alone had been received, to be translated 

 into the three official languages — English, French, 

 and German — and summarised for discussion by care- 

 fully selected reporters. The discussions were on 

 these summarised reports, and as the resolutions 

 voted on after their discussion reach 4500 words in 

 English, 5500 in French, and about the same in the 

 German readings, it will be seen that much has been 

 attempted. 



The questions on which papers were invited were 

 the following : — (1) The planning of new streets and 

 roads ; (2) the best types of surfacing to be adopted 

 on bridges ; (3) the great question of bituminous 

 construction of macadamised roads ; (4) wood paving ; 

 (5) the best methods of lighting streets and high- 

 ways ; (6) the causes of deterioration of road surfaces 

 noted since 1908 ; (7) the regulation of fast and slow 

 traffic ; (8) the functions of road authorities ; (9) 

 finance and the incidence of taxation necessary for 

 tin.' upkeep of the roads. 



In addition, communications on many important 

 subjects were invited, but on these, although many 

 NO. 2 2 79, VOL. 91] 



of them contained much valuable data, there was no 

 time for discussion. 



The resolutions discussed and voted on are really 

 condensed summaries of the average opinions con- 

 tained in the papers, and therefore have a certain 

 value as indicating the general trend of well-informed 

 opinion on road matters in the year 1912, for on 

 account of the time necessarily occupied in the pre- 

 paration, printing, translation, and summarising 

 most of the conclusions arrived at last week were 

 based on papers written nearly a year ago. 



It was, of course, inevitable that a great mass of 

 tin contributions came from countries where road 

 construction and road problems are not in a very 

 advanced state, so that the real interest to the more 

 scientific members present lay in the opportunities 

 that these meetings give for personal discussion of 

 the problems which are now presenting themselves 

 in this most interesting branch of engineering. 



All who are studying the modern road development 

 which is called for by the steady demand for door to 

 door transport of passengers, as well as goods, know 

 that the question of the time is how to produce road 

 surfaces which are efficient from the point of view of 

 reducing so far as possible the running cost of the 

 vehicles which use them, at the lowest cost for road 

 construction and annual maintenance. 



It is almost unnecessary to repeat what has been 

 so often urged, that road engineering demands as 

 intimate a study of the action of the wheel rolling 

 on the road surface as has been devoted to the same 

 question on railways, with such marked economy in 

 the cost of railway transportation. On account of 

 the widely varying type of the vehicles running on 

 the roads and of the great variety of their means of 

 propulsion, and of the fact that for many years to come 

 horse-drawn as well as mechanically-propelled vehicles 

 will use the same road surface, the problems of con- 

 struction and maintenance are certainly more compli- 

 cated than those of the railway. 



At the informal meetings of the more scientific of 

 the engineers who visited London last week many 

 interesting views were interchanged which cannot fail 

 to further the science of road engineering, as has been 

 found to be the case at the international meetings of 

 the Iron and Steel Institute, where such informal 

 discussions have always been the real feature of the 

 meetings. 



On account of the abundant supply of bituminous 

 binding material provided by the tars and pitches 

 from our gasworks, England has made an exceedingly 

 good start in the science of binding road surfaces with 

 tarry matter. On the other hand, America made her 

 first road developments by using the bitumens which 

 are either obtained from natural deposits or as the 

 residuals from the distillation of some of the earth 

 oils. Quite recently the demand for the various 

 forms of petroleum for power and heating purposes 

 has increased the production of the bituminous resi- 

 duals, and it is likely that the low cost of freight 

 will enable America to supply these residuals to Eng- 

 lish road engineers as a formidable rival to the tars 

 and pitches which have been in use up to the present. 



One of the most interesting features to the scien- 

 tific members of the congress has been the inspection 

 of the trial lengths of roadways laid down by our 

 Road Board to enable various road materials, such 

 as the roadstones, the tars, and bituminous binders, 

 to be tested under fixed and regular conditions of 

 heavy traffic at Sidcup, Wandsworth, Fulham, and 

 on other roads and streets in and near London. In 

 addition, the latest scientific development of road 

 apparatus was shown to the members of the congress 

 at tin 1 National Physical Laboratory at Bushv, where 



