236 



SCIENCE. 



[Vol. XIII. No. 321 



of the axles. Some trials were made to determine the tractive force 

 of this locomotive. It was coupled directly to one of the ordinary 

 steam-locomotives of the Birmingham Tramway Company, and set 

 to haul the latter. The brakes on the steam-locomotive were then 

 gradually tightened until it was brought to rest, when the spring 

 balance indicated a pull of a ton and a half ; the current through 

 the motor at that time being 200 amperes. Previous trials on the 

 line had shown that the ma.ximum pull was required on a six-per- 

 cent grade, where it amounted to 1,800 pounds : so the electric 

 locomotive has a margin of over 50 per cent of tractive power above 

 that actually required in the ordinary working of the line. While 

 it is to be hoped that the experiments in Birmingham will succeed, 

 yet storage-batteries have hardly reached that state of perfection 

 that they can compete, as far as expense goes, with steam-engines. 

 While it is still a very doubtful question whether they are more 

 economical than horses for street-car work, it would seem a mis- 

 take to bring them in direct competition with steam. 



The Dimensions of Electrical Units. — Professor Fitz- 

 gerald, in a note communicated to the Physical Society of London, 

 calls attention to the fact that the dimensions of the electric and 

 magnetic inductive capacities are the same, being the inverse of 

 a velocity, the one differing from the other only by a numerical 

 coefficient-. This, Professor Fritzgerald thinks, is very suggestive, 

 and seems to have been hitherto overlooked. He thinks that the 

 two quantities must be proportional to the reciprocal of the square 

 root of the mean kinetic energy of the ether. 



A New Dynamo. — Messrs. Fritsche and Pischon of Berlin 

 have brought out a new wheel-armature dynamo which gives some 

 remarkable results. The armature is built without a core, without 

 cotton insulation, without copper, and without a special commu- 

 tator construction. It is built up of a lattice-work of iron rods, 

 which are separated by air-spaces, and the rods are prolonged as 

 segments of the commutator. The dynamo is multipolar. The 

 smallest of them gives 50 i6-candle-power lamps, at a speed of 240 

 revolutions : the largest supplies 3,500 lamps at 70 revolutions. 

 They are said to be very efficient, which fact, together with their 

 extreme simplicity, will probably cause their extended adoption. 



NOTES AND NEWS. 



The Ericsson Coast Defence Company was incorporated at 

 Albany on Friday, March 22, by George H. Robinson, William 

 Williams, Ericsson F.Bushnell, Cornelius S. Bushnell, and Edward 

 S. Innet. The main idea of the company is to manufacture imple- 

 ments for the defence of the American coasts, and to enlist the in- 

 terest and assistance of the United States Government in the re- 

 sults of the studies and experiments of the late Capt. John Erics- 

 son, who devoted many years and much labor to the subject of our 

 coast defences. The most notable of his inventions in this line is 

 the " Destroyer," a boat built for the destruction of the monitor 

 gunboats. The company claims that the boat has been satisfac- 

 torily tested, and believes that it will receive recognition from the 

 present administration. With all the other inventions left by Capt. 

 Ericsson, the Ericsson Coast Defence Company will have nothing 

 to do ; that is, with inventions which have nothing to do with the 

 subject of coast defence. There are several of the latter inven- 

 tions, notably a perfect caloric engine and the sun-motor, which 

 the executors will proceed to patent at once, or at least as soon as 

 they can act in the matter according to law. Owing to the legal 

 advertising made necessary by the conditions of the will, that docu- 

 ment cannot be probated before May. Every thing has to be 

 turned into cash, and the necessary delay in communicating with 

 the legatees in Sweden and other parts of Europe will prevent for 

 the present the patenting proposed by the executors. This delay, 

 however, does not affect the operations of the Ericsson Coast De- 

 fence Company, which is wholly independent of the will and the 

 legatees. 



— The collection of American precious stones, both in the form 

 of crystals and cut stones, which are to be exhibited at the Paris 

 Exposition, Messrs. Tiffany & Co. have decided to place on exhibi- 

 tion on Friday, Saturday, Monday, and Tuesday, March 29 and 30 

 and April i and 2. This collection is one of the finest that has 



ever been gotten together, and will be in charge of Mr. George F. 

 Kunz, who has devoted considerable time to its preparation. 



— In Nature of March 7, J. Starkie Gardner writes as follows 

 on the origin of coral islands : " Mr. Murray's concise explanation of 

 the formation of coral reefs and islands presents advantages in 

 more than one respect. It demands no a priori assumptions, but 

 begins and ends with that which can be observed, while Darwin's 

 theory requires the preliminary concession of subsidence, which 

 never has been and never perhaps can be observed. It must 

 appear ungracious to question a theory that accords so com- 

 pletely with the natural history of coral islands ; but even this 

 theory requires a geological concession, and that is stability. Coral ' 

 islands, it may be supposed, after all, only differ from other oceanic 

 islands in being crusted over with coral, so that we cannot see 

 their original state ; and the question is, whether we can grant 

 such long periods of stability to them, from our experience of other 

 oceanic islands, which are free from coral, and can therefore be 

 observed. Nearly all oceanic islands are volcanic, and it is prob- 

 able that their elevation coincides more or less with the period of 

 volcanic activity somewhere along their line. It is obvious that 

 coral islands are not formed during this phase, because no theory 

 would then hold good ; the peaks would grow through and carry 

 up the coral, which might leave only such small traces of its ex- 

 istence as we find in a single spot in Madeira. It would not be 

 unreasonable to suppose, that, if the expansive and elevating force 

 were withdrawn, the peaks would slowly subside ; and that, if 

 there are some hues of elevation, there must be others of subsid- 

 ence, unless the earth is as a whole growing in bulk. Darwin 

 claims the existence of areas of subsidence, and that these are 

 eminently favorable to coral-growth ; and it is quite apparent that 

 if the Island of Madeira were to sink, as it has undoubtedly risen, 

 its last appearance in a coral sea would be as an atoll. We shall 

 never see the interior structure of a stationary or subsiding coral 

 island, and can only look for a re-elevated example with a crust 

 that has been protected from solution whilst dead and submerged, 

 and yet not sufficiently so to mask the core. In submitting geo- 

 logical considerations, I am not questioning any of Mr. Murray's 

 observations, which are in every way admirable, though it does 

 appear to me doubtful whether atolls could increase outwards in 

 deep water on their own talus, in face of the dissolution of dead 

 coral that is claimed to take place in the interior of the lagoons, 

 and yet more so in deeper water." 



— We note with pleasure the advancement to the grade of com- 

 mander in the navy of Commander R. B. Bradford, who for the 

 past few years has had complete control of the various electric- 

 light instalments in our men-of-war and at the different naval sta- 

 tions. The unvarying success that these numerous plants have 

 met with are well-deserved tributes to the abilities of the naval 

 inspector of electric-lighting. 



— Marcus M. Hartog, in Nature, writing of the inheritance of 

 acquired characters, says, " A very z\xox\% a priori objection to the 

 line on which most experiments on the inheritance of acquired 

 characters are carried on is the following. These experiments in- 

 volve mutilation ; and a tendency to transmit characters so pro- 

 duced would, considering that every accident or fight produces 

 some slight mutilation, involve the animals in a process of degener- 

 ation : hence the tendency to transmit the characters acquired by 

 mutilation would be constantly bred out by natural selection. But a 

 tendency to transmit characters acquired by habit in youth rests on 

 quite another basis, and would tend to the conservation of the race. 

 I do not know if observations have been made on the physique of the 

 offspring of persons engaged in trades where apprenticeship begins 

 before puberty : they would be most valuable. But the following 

 case seems to me to be thoroughly to the point. A. B. is moder- 

 ately myopic and very astigmatic in the left eye ; extremely myopic 

 in the right. As the left eye gave such bad images for near objects, 

 he was compelled in childhood to mask it, and acquired the habit 

 of leaning his head on his left arm for writing, so as to blind that 

 eye ; or of resting the left temple and eye on the hand, with the 

 elbow on the table. At the age of fifteen the eyes were equalized by 

 the use of suitable spectacles, and he soon lost the habit completely 



