October, 1910. 



KNOWLEDGE. 



419 



PHYSICS. 



By W. D. Eggak. M.A. 



SKISMOLOGICAL INVESTIGATIONS.— The fifteenth 

 report of the Committee appointed by the British Association 

 contains much interesting matter. For one thing it appears 

 that more sensitive instruments are wanted. Earthqviake 

 tremors are continually passing beneath ob.servatories all over 

 the world without leaving any record, because the apparatus 

 used for detecting the disturbance is too clumsy. Mr. Milne's 

 observatory at Shide, in the Isle of Wight, fitted with the B.A. 

 type of instrument, recorded eight of the after-shocks of the 

 Messina earth(iuake. of which only two seem to have been 

 recorded at Laibach. Gottingen and Hamburg, which are 

 nearer to the origin than the Isle of Wight, but are fitted with 

 different types of instrument. Between July 1st and Dec. 31st. 

 1909, Shide Observatory noted two hundred and se\'enty-nine 

 earthquakes. In the same period Hamburg recorded one 

 hundred and twenty-three, Strassburg sixty-four, and Laibach 

 forty-two. .After the earthquake in Jamaica which devastated 

 Kingston in January. 1907, fifty-one of the after-shocks reached 

 Great Britain, the time taken for the tremor to travel from 

 Jauiaica. ,i distance of 67°. being in every case about 43 

 minutes. This was the first time that small after-shocks had 

 been noticed at places far removed from their epicentral area, 

 and it is remarkable that in each case the British .Association 

 type of instrument made the record. It is evident that a high 

 degree of sensitiveness has been attained in this type : and a 

 new field of research has been opened up for which a still 

 more sensitive instrument may ultimately be needed. 



BOARD OF TRADE STANDARD OHM.— On January 

 10th, 1910, His late Majesty King Edward VII. in Council 

 raised the British Standard Ohm through one centigrade 

 degree. The reason for this elevation is as follows. The 

 Interuational Ohm is the resistance offered to an unvarying 

 electric current by a column of mercury at the temperature of 

 melting ice 14'4521 grammes in mass of a constant cross 

 sectional area and of a length of 106'300 centimetres. The 

 Board of Trade Standard Ohm was, until the above date, the 

 resistance between the copper terminals of a certain instrument 

 when the coil of insulated wire connected to the aforesaid 

 terminals is in all parts at a temperature of 15'4 C. It had 

 been found, at the last verification of the Standard Ohm. 

 .Ampere and Volt, that the Board of Trade standards would 

 agree with the international standards with sufficient precision 

 if ouly the temperature specified were 16'4 C. instead of 15'4 C. 

 The required degree of accuracy is, for the Ohm, within one 

 hundredth part of one per cent. : for the other standards 

 within one tenth part of one per cent. The change has been 

 made, and is one more step in the direction of international 

 agreement. 



ZOOLOGY. 



BRITISH ASSOCIATION— PRESIDENT'S ADDRESS 

 IN SECTION D. IZOOLOGY).— In his presidential address 

 to Section D. Professor G. C. Bourne discussed to begin with 

 the subject of Morphology, which he pointed out is no longer 



in favour in this country, and among a section of the 

 zoological has almost fallen into disgrace. He showed that it 

 deserves the credit of having done well in the past, but if it is 

 to be anything more than a descriptive science, if it is to 

 progress any further in the discovery of the relations of cause 

 and effect, it must alter its methods. Professor Bourne 

 contended that an enquiry into the causes which produce 

 alterations is as much the province of and is as fitly to be 

 called morphology as a discussion of the significance of the 

 patterns of the molar teeth of mammals, or a disputation about 

 the origin of the coclomic cavities of vertebrated or 

 invertebrated animals. 



As indicating the kind of work to be done, Professor Bourne 

 alluded to the e\idence that is beginning to accumulate which 

 shows that external conditions may produce changes in the germ 

 cells as weir as in the body (soma), and that such changes 

 may be specific and of the same kind as similarly produced 

 somatic changes. He further stated that there is evidence 

 that such germinal changes are inherited. 



.An instance brought forward was the work of Tower upon 

 the Colorado Beetle {Lcpthiotarsa deceiiilhieata) where 

 males and females were subjected to very hot and dry conditions 

 (such as are usually productive of albinic examplesi during the 

 maturation and fertilization of the first three batches of eggs. 

 These as soon as laid were removed to normal conditions, 

 but, nevertheless, of the ninety-eight adult beetles reared 

 from them, eighty-two were albinic, of a variety known as 

 pallida. Two shewed characters of another albinic variety 

 and fourteen were unmodified. The same insects were 

 allowed to lay their subsequent batches of eggs under normal 

 conditions, and all the offspring were unmodified. 



MIGRATORY MOVEMENTS OF BIRDS.— Dr. C. J. 

 Patten, who described his investigations upon the size of 

 the testes with Sanderlings, claimed that he had found 

 the kev to souie problems regarding the migratory movements 

 of birds at the breeding season. 



MITOKINETISM. — At a joint meeting with the Botanical 

 Section, Professor Hartog demonstrated that in cell division 

 the cell spindle is homopolar with respect to osmosis currents, 

 electrolytic and electrostatic force, and as, therefore, magnetism 

 is out of the question, he concluded that mitokinetism is a 

 new force unknown so far outside the living cell. 



ARTIFICIAL PARTHENOGENESIS. — The investiga- 

 tions described by Dr. Edward Hintle dealt with the 

 cytological changes that follow the chemical fertilization of 

 the e.ggs of sea urchins by means of a fatty monobasic acid, 

 and the suggestion was made as their result that the known 

 facts of artificial parthenogenesis might be competent to 

 explain the origin of cancer. 



SEX AND IMMUNITY. — The Parasite. Sacciilina. 

 causes its male host, the spider crab {lnacliHs\ to assume 

 adult female characters e.\ternally, and after the death of the 

 parasite to produce ova from its testes. Young females are 

 caused to assume adult female characters prematurely. Mr. 

 Geoffrey Smith sought to show that this is an immunity 

 phenomenon. 



REYIKWS. 



ASTRONOMY. 



.4 Xiinticiil Star Chart.— By Capt. D. H. Bernard. 

 33-in. X 19-in. 



(Brown & Son, Glasgow: Price 15 net.) 



This Chart, though primarily designed for the use of Naxal 

 Officers and at sea, is calculated to be exceedingly useful to all 

 classes of Astronomers. It comprises, on Mercator's projection, 

 all the stars between 70° of N. and 70° of S. Declination 

 which appear in the Nautical Almanac ; and therefore 

 includes all the prominent and important naked-eye stars 



within the limits in question. The dimensions of the chart 

 being 33-in. X 19-in., the scale is large and the stars are 

 engraved large in size. The back of the chart is occupied 

 with a varied amount of information, arranged in panels, 

 such as brief remarks on the constellations, individual stars, and 

 the planets; and various hints and suggestions relating to 

 leading weather facts, the treatment of chronometers, nautical 

 measurements, the use and misuse of the word " Knot," 

 together with a Table of the Right .Ascensions and Declinations 

 of the one-hundred and thirty stars which are mapped. By 

 the way. the epoch of this list is not given. Altogether we 

 recommend this chart as one of wide general usefulness. 



