March 16, 1883.1 



SCIENCE. 



167 



Lincll. sp , and P. Reinii Geyl. The fresh-water or 

 brackish character of these deposits is proved by the 

 occurrence of true and undoubted Cyrena sp. and 

 Estheria. 



The cretaceous fossils of Yesso are carefully exam- 

 ined by Naumann (Mitth. deutsch. ostadat. gesellsch., 

 heft 21), and partly (thirteen species) identified 

 with Indian types, partly with shells described by 

 Schmidt, from Sachalin. His result is, that the 

 Ammonite-beds of Yesso are upper-cretaceous, and 

 correspond especially to the Ootatoor-group of India. 



During the last vacation, I got, from Shikoku, 

 sandstones which are also upper cretaceous. They 

 are quite filled with a Trigonia of the scabra-group, 

 probably T. aliformis Park. Two other Trigoniae, 

 which I cannot determine «'ith the literature at hand, 

 fragments of Xatica and Hamites, accompany it. 

 The said sandstones have been met with at Oruuo, 

 district of Itanagori. province of Awa; Tannomura, 

 district of Katsuragori. province of Awa; Yassuda- 

 mura, district of Akigori, province of Tosa, — on the 

 island of yiiikoku. 



The tertiary strata are rather thick. Those which 

 have been studied by Dr. Brauns (Mem. Tokio uiiiv., 

 no. 4, ISSl) and A. JS'athorst [Seensk. akad. hanclL, 

 1882) are pliocene, most of the shells and plants 

 described being identical with living ones. Miocene, 

 or older strata, are not yet recognized with certainty. 



Glacial phenomena have not left any traces in 

 Japan. 1 I conclude here with the remark that the 

 list of your Explication contains some volcanoes 

 (uos. 8 and 9, p. 114; nos. 4 and 10, p. 11.5) which 

 I cannot make out. More complete are the lists of 

 Naumann (Yokohama, 1S7S) and Milne (Trans, seis- 

 mol. !>oc. Japan, iv. 1882): but even these are not 

 complete; for a recent revision I made gave forty- 

 eight volcanoes which are active now, or have been 

 active within historical time, or are still in the solfa- 

 tara state. Besides that, I know about forty cones 

 which are probalily prior to human i-ecoi-d, and date 

 back as far as the pliocene series, which is very often 

 tufaceous or filled with pumice-fragments. 



PERFECT INTERFERENCE OF SOUND 

 BY TELEPHONE. 



Suppose we have two telephones having the poles 

 of their magnets similarly placed, and so connected 

 with a circuit that a cui-rent will traverse their coils 

 in the same direction. It is evident that any electric 

 current passing will cause a simultaneous movement 

 in the same direction in the diaphragms of both tele- 

 phones. Now, if we conceive the current reversed in 

 one of the telephones, the motions will have opposite 

 signs. It follows, then, that the currents due to the 

 vibration of the diaphragm of a third telephone in the 

 circuit will produce in the two telephones vibrations 

 of opposite j)fta.9es; the sounds produced, therefore, 

 will differ by a half-wave length. The same current 

 which in one telephone produces a condensation will 

 in the other i^roduce a rarefaction. 



The experiment, as successfully tried in the physi- 

 cal laboratory of Dartmouth college by Professor 

 Emerson and myself, was arranged as follows: the 

 mouths of two similar telephones were placed before 

 the extremities of a Y-shaped tube, and the sound 

 from both telephones conducted to the ear by rubber 

 tubing. A reversing-switch was placed in the circuit, 

 by means of which the direction of the current in 



1 The writer ignores the discovery of Prof. J. Milne of the 

 engineering school of Tolslo, at the large mountain of Gwassan, 

 northern part of Nipon, where are large howMers and roches 

 viovtonn^es, — the product of glacial action. — J. M. 



one of the telephones could be changed; in this way 

 could be produced at will coincidence, or interference 

 of sound. Each branch of the Y-tube was of rub- 

 ber, so that either arm could be closed by pinching. 

 Organ-pipes of various lengths were sounded near a 

 telephone in a neighboring building. It was found, 

 that, when arranged for interference, the pinching of 

 either of the branch-pipes produced a very decided 

 increase in the intensity of the sound ; when reversed, 

 an equally decided decrease. The inequality in the 

 intensity of the sounds due to the two telephones was 

 found to be the chief difficulty in producing complete 

 interference; but by partly closing one branch, so as 

 to weaken the stronger sound, the effect was much 

 improved. In several trials the interference was 

 .complete, no sound whatever being audible. The 

 rapid reversal by the switch gave a sharp contrast 

 between the strengthening and the weakening effect. 

 This method of demonstrating the phenomenon of 

 interference has obviously the advantage of apj)lica- 

 bility to sounds of any pitch. With singing, the in- 

 terference was very satisfactory, especially with the 

 lower notes; in conversation, however, the sound' is 

 not so much weakened, but the quality is perceptibly 

 changed. The vowels seemed to suffer much more 

 than the consonants. C. S. Cook. 



RAILWAY-ACCIDENTS IN 1S8S. 



The statistics of railroad operation in this country 

 are far too incomplete- and mireliable to admit of 

 drawing any very general conclusions. Certain facts, 

 however, appear with sufficient distinctness to show- 

 some very grave defects in the system under which 

 our roads are worked. The liailroad yazette pub- 

 lishes monthly and annually a list of accidents to 

 trains while in motion. This, however, does not in- 

 clude over twelve per cent of the whole number of 

 casualties. Again, accidents not resulting in loss of 

 life or in serious damage to i^roperty are rarely re- 

 corded ; though in many cases the blame is not less 

 great, and the lesson conveyed not less important. 

 The total number of train-accidents for the past ten 

 years is returned as below ; the second horizontal col- 

 umn showing the actual number, and the third col- 

 umn the number per thousand miles of road in 

 operation : — 



1,365 

 12.4 



If we regard the second line alone, the figures 

 would seem to be sufficiently discouraging, as there 

 is a steady increase in the number of accidents from 

 1878 to 1881. We must, however, take into account 

 the growth of the railroad-system. This is done in 

 the third line; and here, again, while we find a some- 

 what less rate of increase, the fact still remains, that 

 our roads are not growing safer as they expand in 

 extent. 



If we examine in detail the causes of accidents, we 

 shall see that they are less dependent upon the total 

 length of roads in operation, than upon the density 

 of the traffic; in accordance with the law, that failures 

 of track and bridges are approximately in proportion 

 to the length of road, while the number of collisions 

 is in proportion to the square of the number of trains. 



