174 



♦ KNOWLEDGE 



[March 23, 1883. 



proportion with the nitro-glyccrino. The process of manu- 

 facture is dangerous, and the cost about four times that of 

 gunpowder, while its power is, perhaps, ten times greater. 

 Besides dynamite, other explosive compounds have been 

 made from nitroglycerine, such as Ditalline, a combination 

 of wood gunpowder soaked with this terrible oil, while 

 liilwfractrnr consists of fifty-two parts of nitroglycerine, 

 thirty of silex, twelve of coal-dust, and two of sulphur. 

 Then there are varieties known respectively as colonia 

 powder, lignose, sebastine, hcracline, and fulminatinc. — 

 P. R. 



The amount of light given out Ijy a gas-flame depends 

 upon the temperature to which the particles of solid carbon 

 in the flame are raised, and Dr. Tyndall has shown that of 

 the radiant energy set up in such a flame, only the l-25th 

 part is luminous ; the hot products of combustion carry 

 off at least four times as much energy as is radiated, so 

 that not more than one-hundredth part of the heat evolved 

 in combustion is converted into light. 



At a recent meeting of the Academic des Sciences, M. 

 Boussingault showed the members an old bronze chisel 

 found in Peru, of the Incarial period, remarking that he 

 had never been able to produce the hardening to which 

 the old bronze was supposed to be subjected. 



The extensions which are now being rapidly carried out 

 at the jSTew-street Railway Station, Birmingham, of the 

 London and North- Western and Midland Railway Com- 

 panies, will, it is claimed, when complete, render it the 

 largest station in the world. The station will cover more 

 tlian eleven acres, and the cost of the alterations is esti- 

 mated at £250,000. The new platform accommodation 

 will be nearly 3,000 ft. in length. 



The Jiaihcai/ Age publishes a summary of railway con- 

 struction in the United States for the year 1882. The 

 account covers only the main track, and shows the con- 

 struction in States and territories. On 342 lines the aggre- 

 gate is 11,343 miles, or about 2,000 miles more than in 

 1881, which exceeded any previous year by 2,000 miles. 

 The construction is divided as follows : — Five New England 

 States, 531 miles; four Middle States, 1,315 J miles; five 

 Middle Western States, 2,0771 miles ; eleven Southern 

 States, 1,4901 miles; four in Missouri river belt, 2,0G31 

 miles; five in Kansas belt, 2,1 57 1- miles; five in Colorado 

 belt, 1,165 miles; six in Pacific belt, 1,020 miles. 



The St. Gothard Tunnel has proved a great success, and 

 is causing quite a stir in France and other countries, as 

 may be seen from the fact that a bill providing for the 

 construction of a new direct railway line between Calais 

 and Marseilles has been laid before the French Chamber 

 of Deputies. The promoters recommend their bill to 

 the Chamber on the ground that the opening of 

 the Gothard line has seriously threatened the traffic 

 throughout France with Italy, and that it is urgently 

 necessary that France .should take prompt steps to 

 re-establish tlie claims of Marseilles over those of Genoa 

 as a shipping port. The uneasiness is evinced elsewhere, 

 as, according to the German press, a committee, established 

 at Kempten, ha.s, in conjunction with several Bavarian 

 corporations, urged upon the Austrian Government the 

 construction of the proposed railway from Innsbruck to 

 Imst, on the Bavarian frontier. The extension of the line 

 to Augsburg, vid Partenkirchen, and to Ulm, c/i^ Kempten, 

 is also spoken of. The section from Innsbruck to Imst is 



■about 5G miles long, and is estiuiated to cost slightly over 

 i/ 1,000,000. It is remarked that this new line and its 

 connections would probably regain for the Austrian lines 

 a good portion of the through traffic for the East, which 

 the opening of the St. Gothard tunnel has lately diverted 

 from them. 



A DEi'UTATiox from the Leeds Corporation called the 

 other day at the Daili/ Teli-.grapli offices, Fleet-street, 

 where they spent some hours and saw the practical 

 application of the Fyfe-Main arc lamps in lighting the 

 machine and folding-rooms during the printing of the 

 paper. They were impressed with the suitability and 

 steadiness of the light. Twelve of these lamps, said to- 

 be of three thousand actual candle-power, recently sent to- 

 Australia, have been selected to light the Houses of 

 Parliament, Sydney, New South Wales. 



There is an automatic clock at the Stock Exchange^ 

 which has now performed very well for six months, in- 

 vented by a M. Dardeme. The winding apparatus consists 

 of a small windmill, fixed in a chimney, or any other place; 

 where a tolerably constant current of air can be relied 

 upon. By means of a reversed train of multiplying wheels 

 this windmill is continually driving a Hughens's endless 

 chain remontoire — a device well-known to clock-makers. 

 A pawl acting on a wheel prevents the motor from turning 

 the wrong way, and, by a simple arrangement, whenever 

 the weight is wound up right to the top, the motion is 

 checked by a friction brake automatically applied to the 

 anemometer by the raised weight lifting a lever. When 

 the weight is thus raised to the top, the clock has a suffi- 

 cient store of energy to go for eight days or more, so that 

 it will be seen that it is by no means dependent on a 

 regular current of air. The Belgian Government has for 

 the past two years adopted this system of clocks on the 

 State railways, and we are informed that they are now 

 being tested by certain English railway companies with a 

 view to their adoption. — Engineer. 



Does the increasing transfer of iron from the interior to 

 the surface of the earth exercise any sensible meteorological 

 influence ? Is it in any marked way influential on electric 

 currents, and thence does it affect magnetic storms 1 This 

 is a question which needs a little thought to answer safely. 

 The development of railways, and the almost imiversal 

 substitution of iron for wood wherever it is practicable to 

 use that metal, must surely exercise a decided influence of 

 its own. Every year more and more of the iron formerly 

 buried deep in the earth is spread upon its surface, and it 

 is surely reasonable to assume that, electrically at least, 

 some effect is produced ; how far we may venture, as some 

 seem now disposed to do, to translate this into a meteoro- 

 logical agency is a problem for science to determine. — P. R. 



jNIr. Stroh, during a discussion at the last meeting of 

 the Society of Telegraph Engineers, described a highly 

 ingenious experiment with the microphone, from which he- J 

 deduced that " during the time when the carbons ara<| 

 really in what is called microphonic contact, they are not 

 in contact at all, or, at all events, that there is a repellent-l 

 action at the point of contact" In the experimental j 

 apparatus one small rod of carbon was attached at one end 

 to an almost frictionless oscillating rod, having on itai 

 opposite side an extremely light concave reflector. The^ 

 other end of this cai'bon rod fell across another carbon rod, 

 which was fixed. The displacement of a spot of light 1 

 reflected by the mirror showed that tlie upper carbon was 

 repelled through 1 •2000th part of a millimetre. 



