April 1 1, 1895J 



NATURE 



563 



to error. The inconvenience of the change to the metric system 

 was only felt by the workmen for a few days. In his evidence, 

 Dr. Gladstone estimated that in the elementary schools about 350 

 hours were occupied in teaching our cumbrous system of weights 

 and measures. As the children had to learn decimals, very 

 little more time would be needed by them for learning the 

 metric system. A chart explaining the metric system was now 

 to be found in nearly all the London schools, and lately it had 

 been decided to supply actual examples of the metre and litre 

 to such schools as asked for them. The metric system was but 

 partially taught in the schools, for the teaching involved 

 additional labour, and was not insisted on by the inspectors. 

 The introduclion of the metric system would be much facilitated 

 if the system were compulsory in the elementary schools. 



In a paper read before a recent meeting of the Academic des 

 Sciences {Comptcs rendns, cxx. p. 611), M. Lucien Poincarc 

 described some experiments on secondary batteries he has been 

 performing. With a view of reducing the losses that take place 

 in the ordinary lead accumulator, the author has tried to obtain 

 a battery with liquid metallic electrodes. For this purpose 

 mercury has been employed, and as it would not do to employ 

 an acid as the electrolyte, since the hydrogen would be liberated 

 and thus cause a waste of energy, a solution of a salt is used. 

 Under these circumstances an amalgam is formed at the cathode, 

 which, together with the mercury of the anode, forms a second- 

 ary cell. Of all the different salts tried, the most interesting 

 results have been obtained with the haloid salts of the alkaline 

 metals. With these salts the electromotive force of the 

 secondary battery is about two volts, but in the case of the 

 chlorides and bromides, the chlorine or bromine combines with 

 the positive mercury, forming a badly-conducting layer, so that 

 the output of the cells is not satisfactory. With a solution of 

 iodideof sodium, however, very salisfactory results are obtained, 

 for as long as the solution is kept sufficiently concentrated, the 

 current density during the charging is not too great, and the 

 positive electrode has a larger surface than the negative elec- 

 trode, no djposit is formed on the anode. Hence by this 

 arrangement a secondary cell is obtained in which the two 

 electrodes remain, after the charge, entirely metallic, so that 

 the internal resistance does not increase as the cell is charged. 

 The efficiency of these cells amounts to very nearly 90 per cent., 

 the electromotive force, when fully charged, being I '85 volts. 

 The capacity per kilogram does not differ much from that 

 obtained with ordinary lead accumulators, being about 10 

 ampere-hours. A very important point about this form of cell 

 is that the density of the discharge current is immaterial, 

 and they may be completely discharged without in any way 

 deteriorating. 



We have received from Prof. G. Hellmann an interesting 

 pamphlet entitled "Contribution to the Bibliography of 

 Meteorology and Terrestrial Magnetism in the Fifteenth, Six- 

 teenth, and Seventeenth Centuries." The work was prepared 

 for the Report of the Chicago Meteorological Congress, and 

 contains a list and brief bibliographical notes of 272 old books 

 in Dr. Ilellm^nn's library, arranged under the authors' names, 

 with cross references under subjects and dates. This pamphlet 

 is of considerable value to meteorologists, as the early literature 

 of this subject is as yet little known, and no meteorological 

 institute is as rich in the older literature as the library in ques- 

 tion. Arranging the books according to the language in which 

 they were written, Ur. Hellmann shows that the authors com- 

 paratively seldom employed their native language, as 157 of 

 the works are in Latin. There is also a preponderance of 

 Italian works, as in the seventeenth century Italy probably 

 contributed more to meteorology than .all the other nations of 

 Europe. Many of the works describe! are exceediigly scarce. 



Since the great Japanese earthquake of 1855, the strongest 

 shock felt in Tokyo was that of last June 24. No house was 

 absolutely destroyed, but in the lower parts of the city many 

 brick buildings were damaged and chimneys thrown down. The 

 total land-area disturbed was 42,000 square miles. The 

 diagram of the earthquake, taken by a large-motion seismo- 

 graph at Tokyo, is given by Messrs. Sekiya and Omori in a 

 short but valuable paper (Journ. of the Coll. of Science, Imp. 

 Univ., Tokyo, Japan, vol. vii. part v. 1894). This diagram 

 being on the natural scile, the preliminary tremors are not 

 shown, and during the first two seconds of the record the motion 

 was already strong. It then became suddenly violent, the 

 ground moving 37 ram., followed by a counter movement of 

 73 mm., the maximum horizontal displacement during the 

 earthquake. At about the same time, the maximum vertical 

 motion of lo mm. occurred. The movement, which lasted 

 altogether 44 minutes, soon became comparatively weak, and 

 it is no doubt to the small number of violent oscillations that 

 the slight amount of damage is due. As usual, the direction 

 of motion changed during the earthquake, but the maximuui 

 horizontal motion was directed towards S. 70° W. , and this is 

 identical with the mean direction of overturning of 245 stone 

 lanterns in different parts of Tokyo. 



The Natural History Society of Queensland, established in 

 the beginning of 1892, has progressed so well that it is able to 

 issue a volume of Transactions. The volume should prove to 

 be a useful contribution to the literature on the natural history 

 of the colony. 



The fifteenth volume of observations of " Rainfall in the 

 East Indian Archipelago," published by the Government of 

 Netherlands, India, has been received. The volume is edited 

 by Mr. Van der Stok, the director of the observatory at 

 Batavia, and it comprises observations made at 194 stations, of 

 which 104 are in Java and Madoera, and ninety in Sumatra and 

 the different islands of the Eastern Archipelago. 



In the Geological Magazine for April appears a translation of 

 a Swedish paper by Prof. Lindstrom, on the discovery of 

 Cyathaspis in the Silurian formation of Gotland. In the cutting of 

 canals for the drainage of marshy tracts of the island, many good 

 exposures have been made of the [fossiliferous marl-shales that 

 underlie the famous limestones with the operculate coral 

 Khizophyllum. Among the fossils obtained from these shales 

 were a pair of dorsal shields of a Pteraspidian fish. Hitherto 

 the oldest known indubitable fish-remains date from the Ludlow 

 epoch, but the Gotland beds are of Wenlock age. It is pointed 

 out that since the vertebrate character of the Cambrian cono- 

 donts has been disproved,. and the supposed Ordovician fish- 

 remains of North America are very doubtfully of that age, 

 these Gotland fossils are, for the present, the ollest known 

 Vertebrates. 



First among the new editions receive! within the past few 

 days is Prof. James Dana's " Manual of Geology," published 

 by the American Book Company. The appearance of this 

 fourth edition of Prof. Dana's classical work, makes us marvel 

 at the energy of the eminent author who, though now eighty- 

 three years of age, could rewrite the whole of the matter in such 

 a ponderous volume as the "Manual," and add one hundred 

 and fifty pages to what was published in the third edition. It 

 is hardly necessary to say that a multitude of new principles, 

 new theories, and new facts, in all branches of geology, have been 

 included in the new edition. "The Partition of Africa" 

 (Stanford), by Mr. J. Scott Keltie, has reached a second 

 edition, after two years of life. The many events that have 

 taken place in Africa during this time are all given considera- 

 tion. Another volume which has attained the eminence of a 



NO. 1328 VOL. 51] 



