290 



NATURE 



[May 5, 1910 



A PAPER on the effects of sewage and sewage gases on 

 Portland cement concrete was read at the Concrete Insti- 

 tute on April 21 by Mr. Sidney H. Chambers, surveyor to 

 the Hampton Urban District Council, and appears in the 

 Builder for April 30. Mr. Chambers has had special oppor- 

 tunities for stud^'ing this problem during the past five or 

 six years, and has come to the conclusion that the gases 

 in solution in sewage, and those expelled from it, arising 

 from its decomposition, do act injuriously upon Portland 

 cement concrete, even when the concrete is constituted of 

 sound and good materials. However, little danger from 

 erosion need be feared provided one or other of the follow- 

 ing factors be absent : — (a) a high degree of putrescence 

 o*^ the sewage ; (b) a moistened surface, which held or 

 absorbed the putrid gases ; (c) the presence of a free air 

 supply. In one chamber under the author's observation, as 

 the level of the liquid fell it left the concrete wetted with 

 a liquid containing sulphuretted hydrogen in solution. This 

 wet surface was then exposed to the action of the air 

 supply, which oxidised the sulphuretted hydrogen with the 

 production of sulphur and sulphuric acid, and led to the 

 decomposition of the concrete, the lime being converted 

 finally into sulphate of lime. The exact nature of the inter- 

 mediate compounds cannot be stated, but it is probable 

 that the active agent is sulphurous acid, as cement is in- 

 soluble in sulphuric acid. The decomposed concrete was 

 washed away at the next rising of the liquid, thus exposing 

 a fresh surface to the action. The continuation of this 

 cycle led to the formation of grooves at the varying liqu'd- 

 level. 



Messrs. Sw.an Sonnenschein and Co. will publish in 

 the course of the next fortnight a volume to be entitled 

 " The Signs and Symbols of Primordial Man," in which 

 Dr. Albert Churchward explains the evolution of reUgious 

 doctrines from the eschatology of the ancient Egyptians. 



A CLEARANCE Catalogue of a miscellaneous collection of 

 books, including works on America, Africa, &c., various 

 domestic animals, and general natural history and litera- 

 ture, has just been issued by Messrs. John Wheldon and 

 Co., Great Queen Street, Kingsway, W.C. The same firm 

 announces the publication of a work, to be issued in 

 twenty-five quarterly parts, on " South American Ornith- 

 ology : a Manual of the Birds of Continental South 

 America, from the Isthmus of Panama to the Straits of 

 Magellan," edited by Mr. H. Kirke Swann. 



MM. Gauthier-Villars, of Paris, have issued in their 

 ■" Savants du Jour " series a monograph, by M. Ernest 

 Lebon, dealing with Prof. Gaston Darboux and his work. 

 The book opens with a biography of the distinguished 

 mathematician and a list of the many distinctions conferred 

 upon him. The remaining six sections are concerned with 

 Prof. Darboux's contributions to mathematical science, and 

 contain several appreciations of them by French men of 

 science. It may be noted that Prof. Darboux's writings 

 number 419. The volume, which costs 7 francs, contains 

 an excellent portrait of Prof. Darboux. 



We have received from Messrs. Newton and Co. an 

 advance proof of the first portion of their new catalogue 

 concerned with " Apps-Newton Induction Coils, X-Ray, 

 High-frequency, Static, and other Electrical Apparatus for 

 Medical Work." An introductory section, which precedes 

 the price-list, provides the general medical practitioner with 

 the information needed to enable a beginning to be made 

 in the use of electrical methods in his practice. The cata- 

 logue serves, incidentally, to show with what powerful aids 

 recent developments in electrical science have provided 

 present-day physicians and surgeons. The contents of the 



NO. 2 II 4, VOL. 83] 



list, arranged as they are so as to make reference easy, 

 will prove of great interest, not only to medical men, but 

 also to electricians. 



Messrs. Kegan Paul, Trench, Trubner and Co., Ltd., 

 have published an eighteenth edition of the late Mr. 

 Win wood Reade's " The Martyrdom of Man." Reade, 

 who died in 1875, in his thirty-sixth year, said of this 

 book of his that in commencing it he intended " to prove 

 that Negroland or Inner Africa is not cut off from the 

 main-stream of events as writers of philosophical history 

 have always maintained, but that it is connected, by means 

 of Islam, with the lands of the East, and also that it 

 has, by means of the slave trade, powerfully influenced 

 the moral history of Europe, and the political history of 

 the United States. But I was gradually led from the 

 history of Africa into writing the history of the world." 



OUR ASTRONOMICAL COLUMN. 



Halley's Comet. — Attempts to observe Halley's comet, 

 with binoculars or naked eye, during the past week have 

 shown that it is by no means an easy object, especially for 

 town-dwellers. By getting out of the town on its eastern 

 side, thereby leaving the inevitable pall of smoky haze 

 behind the observer, the chance of seeing the comet would 

 be enhanced ; otherwise the dawn becomes too bright ere 

 the comet rises above the haze bordering the horizon. As 

 shown in the following table, the conditions with regard 

 to sunrise are now slightly more favourable, but the interval 

 between comet-rise and sunrise again begins to decrease 

 after May 6, and, on this account, observations will become 

 increasingly difficult : — 



Comet rises Sun rises 



a.m. a.m. 



May 6 2.20 4.26 



„ 9 ••• '. — 2.19 4-2T 



,, 12 2.18 4.16 



„ 15 2.37 4-" 



,, 18 3.30 4-7 



Despite the unfavourable conditions, several observers 

 have reported seeing the comet with binoculars. Thus Mr. 

 W. B. Tripp writes that he saw it plainly, from Isleworth, 

 with a binocular field-glass, from 3.0 to 3.30 a.m. on 

 May 3 ; to the naked eye it was a very faint object south 

 of y Pegasi. In addition to a bright nucleus, there 

 appeared to be an appreciable, though short, tail, of which 

 Mr. Tripp sends a rough sketch. Other naked-eye observa- 

 tions have also been recorded. Sir Robert Ball, telegraph- 

 ing to the Times on May 3, said : — " Halley's comet was 

 observed at Cambridge at 3 this morning. The stellar 

 nucleus was between the second and third magnitude, and 

 the tail was 20 minutes long." 



The rapid approach to the earth should make observa- 

 tions easier, the distances, in millions of miles, for the 

 next few days being as follows : — May 6, 56 ; May 10, 41 ; 

 May 14, 27 ; May 18, 16 ; May 20, 14-3. After May 20 

 the comet will recede from us at about the same rate as 

 it is now approaching us, attaining a distance of about 

 42 million miles on May 30. 



Some interesting articles dealing with comets in general, 

 and Halley's in particular, appear in No. 1926 of La 

 Nature (April 23), which is wholly devoted to the subject. 

 M. Jean Mascart discourses on the historical importance 

 of Halley's comet ; M. Rudaux discusses the nature of 

 comets and their orbits, referring to many famous 

 examples ; and M. Touchet contributes a description of 

 comet 1910a. All the articles are profusely illustrated with 

 interesting diagrams and photographs. 



Another interesting article, in which Dr. H. N. Russell 

 discusses the conditions of the present apparition, is pub- 

 lished in the Scientific American for April 16. He points 

 out that the present apparition is a favourable one. and 

 discusses the phenomena which may be observed. One of 

 the illustrations is a reproduction of Prof. Frost's objective- 

 prism spectrum of January 14, in which the cyanogen band 

 is an outstanding feature. Dr. Russell makes some 



