l82 



NATURE 



[December 26, 1907 



notice of part ii., relating to temperature (Nature, vol. 

 Ixxiii., p. 594), where it is explained that the author claims 

 that the observations over the vi^hole earth, collectively, 

 and in the northern and southern hemispheres, separately, 

 show half-yearly and other periods the epochs of which 

 are identical. Part iii. deals with barometric pressure, for 

 which 275s years of observations arc used, but are neces- 

 sarily very unevenly distributed, 2255 years being to the 

 north of the tropics, and only 381 years to the south. 

 The similarity between the curves for the north and south 

 hemispheres is not so pronounced as in ihe case of the 

 temperature curves, as the years available for the south 

 are altogether insufficient for the purpose, but the author 

 thinks that with sufiRcient materials the results would 

 probably be nearly identical. The results with regard to 

 rainfall are much less satisfactory ; the elimination of dis- 

 turbances caused by heavy downpours in thunderstorms 

 requires a much longer period of observation than is at 

 present available. The paper is accompanied by tables and 

 curves showing the variations exhibited by both elements. 



The foundations of geometry form the subject of the 

 presidential address to section iii. of the Royal Society 

 of Canada, by Prof. Alfred Baker, published in the Trans- 

 actions of the society, 1906-7. The author traces the 

 history of the axiom of parallels from an anecdote about 

 Lagrange, and from the early writings on the subject of 

 Gauss, Bolyai, and Lobachevski, and he gives a detailed 

 abstract of Hilbert's assumptions. Referring to an 

 attempt made in 1570 by Sir Henry Savile, of Oxford, to 

 stimulate interest in Greek geometry by explaining the 

 first eight propositions of Euclid to a class of universitv 

 students, and comparing this result with the performance 

 of modern schoolboys, Prof. Baker thinks that a time 

 may come when schoolboys will find no difficultv with the 

 abstractions of Hilbert's geometry, and the truth of Prof. 

 Halsted's claim may be felt that " geometry at last made 

 rigorous is also thereby made more simple." 



The August Bulletin of the Bureau of Standards of 

 Washington contains a detailed comparison of the four 

 most accurate methods of comparing the capacities of 

 condensers, from the pen of Mr. F. W. Grover. He finds 

 that the four are about equal in accuracy when the various 

 sources of error inherent in each method are eliminated. 

 He advocates the use of an auxiliary adjustable air con- 

 denser to enable comparisons to be made by the method 

 of substitution, and shows that the power factor can 

 readily be determined at the same time. This quantity 

 gives valuable information as to the quality of the con- 

 denser, the absorption, and the change of capacity of the 

 condenser with frequency. 



M. Charles F£ry has constructed a very simple calori- 

 meter for determining the calorific power of gases and 

 liquids, and gives a description of it in the November 

 number of the Journal de Physique. The combustion is 

 effected at the base of a glass chimney, the top of which 

 supports a nickel plate pierced with a number of holes. 

 The air necessary for combustion passes down a similar 

 chimney, which is connected at its base w-ith the former. 

 The two junctions of a constantan-copper thermo-circuit 

 are placed at the tops of the chimneys, and M. F6ry finds 

 that the electromotive force in the circuit is strictly pro- 

 portional to the calorific power of the combustible and to 

 the volume of it consumed in unit time. 



Messrs. Bemrose and Sons, Ltd., have published the 

 twelfth volume of the new series of the Reliquary and 

 Illustrated Archaeologist, which contains the quarterly 

 numbers of the review published during 1907. The separate 



NO. 1 99 1, VOL. 77] 



issues have . been referred to from time to time in these 

 columns. It will suffice to state here that the review is 

 now edited by the Rev. Dr. J. Charles Cox, and is devoted 

 to the study of the early Pagan and Christian antiquities 

 of Great Britain, the development of the arts and indus- 

 tries of man in past ages, to the survival of ancient 

 usages, and kindred subjects. The price of the volume is 

 12s. net. 



OUR ASTRONOMICAL COLUMN. 

 Nova Persei, 1901. — To test the question of possible 

 proper motion in Nova Persei (No. 2), Prof. Barnard has 

 recently repeated his measures of the Nova's position in 

 regard to other stars in the neighbourhood, using the 

 40-inch refractor of the Yerkes Observatory. Comparing 

 the results with those obtained in 1901-2, he finds no 

 evidence of measurable motion. The present magnitude of 

 the Nova is about 11-6, the star having apparently in- 

 creased somewhat in brightness of late (Astronomische 

 Nachrichten, No. 4220, p. 323, December 12). 



Provisional Elements for the Spectroscopic Binary 

 a Andromed.^. — In No. 4220 of the Astronomische Nach- 

 richten (p. 327, December 12), Dr. H. Ludendorff pub- 

 lishes a provisional set of elements for the orbit of 

 a AndromedsE, which star has been announced, by several 

 observers, as a spectroscopic binary. This following set 

 of elements has been calculated from the measurements of 

 thirty-eight plates : — 



U = 97od. oc = 7o° 



V= - 14 km. ^=o^^ 



A = 34 km. B = 26km. T=l904Dec. 2 



"1 = 98° a sin / = 36,ooo,ooo km. 



Photographs of Mars. — The second of Prof. Lowell's 

 series of articles on Mars, which is appearing in the 

 Century Magazine, is published in the December number 

 (vol. Ixxv., No. 2, p. 303). In it the author gives an 

 account of the inauguration and the work of, and of the 

 results obtained by, the Lowell-Todd expedition to the 

 Andes for the observation of Mars under conditions which 

 could not be obtained in higher latitudes and less favour- 

 able climates. One of the reproductions illustrating the 

 article shows the Amherst telescope in position at 

 Alianza, Chile, surrounded by the members of the expedi- 

 tion ; five other reproductions show prints from some of 

 the plates obtained, each plate containing from sixty to 

 ninety images of the planets, and, alongside, drawings 

 made at the same time by Prof. Lowell, located some 

 6000 miles away, show how faithfully the photographs 

 confirm the visual observations made at the Lowell Observa- 

 tory. On the best series of photographs, obtained on 

 July 25, are to be seen delicate canaliform markings 

 which entirely refute the suggestions that such markings, 

 previously recorded visually, are merely subjective pheno- 

 mena. 



Prof. Lowell states that the results greatly exceed his 

 most sanguine expectations, and concludes his article with 

 the following paragraph : — " That life is there is founded 

 on no assumption, but on massed evidence that is con- 

 clusive, and the reader should realise that opposition to 

 the idea that we now have proof of life on Mars is not 

 based on reason, but on emotion, however speciously 

 cloaked. All scientific objections have been met and 

 shown untenable as to temperature, snow, &c., but human 

 prejudice, as with the Copernican system or the origin of 

 species, time alone can dispel." 



Saturn app.^rently without Rings. — In the December 

 Bulletin de la Socii'te astronomique de France (p. 513I 

 M. Flammarion discusses the recent observations of 

 Saturn, paying particular attention to the phenomenon of 

 bright knots, observed bv Prof. Campbell, and confirmed 

 bv Prof. Lowell and others. In this connection he repro- 

 duces two drawings made by Bond showing " breaks and 

 prominences " on October 28 and November 3, 1848. 

 These interruptions in the light of the ring were then 

 so easily seen that the observer did not hesitate to explain 

 the phenomenon by the light reflected from the interior 

 edges of the rings. 



