268 Scientific Intelligence. 



part of the pamphlet. From it the reader may draw for him- 

 self a safe conclusion as to how far in the long run observers of 

 the same telescopic object may be expected to differ from each 

 other. 



The question suggested to the mind of most readers will be, 

 whether it would be possible to apply such a system to the 

 stud} 7 of Mars for the purpose of verifying the results claimed 

 by Mr. Percival Lowell, and if it were possible whether it would 

 be worth the trouble. w. b. 



3. UHeure d Paris. — The above is the title of a pamphlet by 

 Jean Mascart, Adjunct Astronomer at the Observatory of 

 Paris, published in 1907 by Gauthiers-Villars, of the Bureau of 

 Longitudes of the same observatory. It is a description of the 

 system for distribution of accurate time from the above observa- 

 tory to the clocks of Paris, preceded by a rather exhaustive his- 

 torical sketch of the whole problem of the measurement of time. 

 The principal facts in the development of the subject are intro- 

 duced and described in chronological order, — the gnomon, transit 

 instrument, astrolabe, quadrant and other astronomical instru- 

 ments, the clepsydra, sundial, clocks, watches and chronometers, 

 and the successive stages of improvements in each of these time- 

 keepers, the different customs among nations as to when the day be- 

 gins and how it was divided, the difficulties of keeping time by the 

 real sun and the introduction of mean time in its place, and finally 

 the adoption of the mean time of a nation's capital for that of the 

 entire country, which, except in France, has given way to the 

 system of Standard Time. 



The author refrains from going into the reasons for France 

 not complying with the general custom, but concludes his disqui- 

 sition with an elaborate description of the equipment for deter- 

 mining time at the Paris Observatory, giving particular attention 

 to the delicate synchronizing apparatus attached to their clocks 

 and the system of distributing time to the various clocks of the 

 city by electricity. He recounts the many difficulties encoun- 

 tered and finally makes an appeal for a reorganization of the 

 system and extending it so as to cover not only Paris, but the 

 whole of France. 



The author's general discussion of the problem of time con- 

 tains many interesting facts well brought together in their proper 

 relation. f. l. c. 



4. Globus-karte. Weltkarte in Teilkarten in einheitlichem 

 Flachenmassstabe mit einer-statistischen Tabelle der selbstdndigen 

 Staaten und der deutschen Kolonien; von F. Sipman. Berlin, 

 1907 (Verlag von Dietrich Reimer). — This quarto pamphlet 

 contains a chart of the world on a scale of 1200 miles to the inch, 

 cut into six segments, each segment extending from the north to 

 the south pole, and embracing sixty degrees of latitude. The 

 segments are in contact at the equator, and all parallels of lati- 

 tude and the central meridians of each segment form a true scale, 

 differing in this l'espeut from a Mercator's projection. Statistical 

 tables of the various governments are included. J. b. 



