Vol. XXm. No. ii.] 



POPTJLAE SCTEITCE l^EWS. 



167 



Slje Popular Scieijce Qews. 



BOSTON, NOVEMBER i, 1889. 



AUSTIN P. NICHOLS, S.B Editor. 



WILLIAM J. ROLFE, Litt.D., . Aasodate Editor. 



The Clubbing List for 1889-90 will be 

 found on the third advertising page. 

 »♦» 



During the past month statements have 

 been sent to all in arrears for subscription to 

 the News. A great many have respomded, 

 but still there remain many more who have 

 not. Please look at the date on the address 

 label of this number, and if you have not paid 

 to January, 1S90, a remittance to that date 

 will be greatly appreciated by the publishers. 



The publishers would also call attention to 

 the small classified advertisements on page 3. 

 This is a new feature in the News, and one 

 likely to be very popular with advertisers 

 desiring a large and high class circulation. 



Extremely wild statements have at various 

 times been made with regard to the question 

 of how fast a locomotive can run, and one 

 hundred miles an hour has been freely talked 

 of by those who are unaware of the facts. 

 Mr. C. E. Stretton, an eminent English 

 engineer, in a communication to the Alechan- 

 ical World., gives some official figures, which 

 show that the highest speed ever accurately- 

 taken was with a Bristol and Exeter broad- 

 gauge engine having nine-foot wheels, which 

 was, in 1853, oflicially timed at a speed of 

 just over eighty miles an hour, for a short 

 distance, upon a falling gradient, with a light 

 load. He also claims that this speed is the 

 maximum that can possibly be obtained with 

 our present types of locomotives, and says the 

 cause of this is that at that speed the resistance 

 of the air, the back-pressure in the cylinders, 

 and the friction altogether, have become so 

 great that they absorb the whole power of the 

 engine, while the back-pressure on the wrong 

 side of the piston becomes greatly increased 

 by the fact that the exhaust steam cannot be 

 got out of the cylinders fast enough. Only a 

 very few reg^ilar trains average fifty miles an 

 hour in actual runs, and we must be content 

 to crawl along at that speed, until some 

 entirely new method of transportation is 

 invented. 



An article in Scribtier's Magazine, by 

 Professor N. S. Shaler, upon the common 

 roads of this country, has attracted much 

 attention. He shows that the wretched con- 

 dition of the average country road is a cause 

 of direct damage and loss to an amount many 

 times greater than would suffice to keep it in 

 good condition. No one who has occasion to 

 drive very far over the highways of New 

 England, will be inclined to disagree with 

 him, but to find a remedy for such a state of 



affairs is not as easy as might at first appear. 

 Local self-government, including the manage- 

 ment of highways, is one of the fundamental 

 institutions of this country, and only an 

 appeal to local pride and interests is likely 

 to cause any improvement in the condition of 

 the highways. The suggested appointment 

 of a special inspector or commissioner of 

 roads, seems to us both impracticable and 

 objectionable. The state of Massachusetts is 

 already afflicted with numberless inspectors 

 and commissioners of everything to which 

 such officials can possibly be attached, and, 

 although they show commendable diligence 

 in drawing their salaries, the actual value of 

 their services to the public is considerably 

 less than nothing. 



One of the most attractive of the American 

 exhibits at the Paris Exposition was that 

 of precious stones, under the supervision of 

 Mr. George F. Kunz, the well-known min- 

 eralogist and expert in gems. Diamonds are 

 already cut in this country in a manner supe- 

 rior to that of many foreign work-shops, and 

 the numerous varieties of rare stones and 

 minerals peculiar to the United States aflbrds 

 abundant opportunity for the development 

 of the lapidaries' art, which has already 

 become quite a flourishing industry. The 

 deposits of silicified wood recently discovered 

 in Arizona are almost unique, and are pre- 

 eminently adapted for ornainental and deco- 

 rative work. 



Dr. W. T. English, bf Pittsburg, Penn., 

 seems to ha\e some very remarkable ideas in 

 regard to the air which the inhabitants of that 

 city, in common with the rest of the world, 

 depend upon to keep up their vital processes. 

 In a paper read before a sanitary convention, 

 he claims that the use of the electric-light is 

 an important sanitary measure, in that it 

 reduces the "oxygen-waste," and he calcu- 

 lates that the grand total of oxygen saved by 

 the use of electric-lights in that city would 

 suffice for the respiratory needs of 115,000 

 people. If there is any element in the world 

 which exists in inexhaustible quantity, it is 

 the atmospheric oxjgen ; but, admitting that 

 the air in the streets of Pittsburg is never 

 replenished by winds or air currents, as the 

 doctor seems to assume, we would suggest 

 that he calculate the amount of oxygen 

 "wasted" in the furnaces of the steam-boilers 

 which drive the electric-lighting machinery. 

 There is as much danger of the gas-lights of 

 Pittsburg using up the supply of atmospheric 

 oxygen, as there is of the catfish in the Ohio 

 river drinking up all the water of that his- 

 torical stream. 



If a current of electricity is passed through 

 a coil of wire with a hole through its centre, 

 and a small iron rod or wire is brought near 

 it, it is drawn into the coil with considerable 



force, and if the current is stopped at the 

 right instant, the ro 1 may be made to jump 

 entirely through the coil. A recent invention, 

 which is based on this principle, consists of a 

 small railroad, slightly raised above the 

 ground, and surrounded at frequent intervals 

 by coils of wire. A hollow steel carriage 

 runs upon the rails, and passes througli. the 

 coils, the electric current being automatically 

 sent through each coil successively, at the 

 proper moment. The steel carriage, which 

 represents the iron rod in the original experi- 

 ment, is drawn through the coils with great 

 force, and it is claimed that a speed of one 

 hundred miles an hour can be easily obtained. 

 Letters and small packages could thus be 

 sent from Boston to New York in two hours, 

 and to Chicago in half a day. On theoretical 

 grounds there would seem to be no reason 

 why the idea is not a practical one, and if the 

 cost of constructing and operating the new 

 style of railroad is not too high to prevent its 

 use, the invention will be a very useful and 

 important one. 



MUSICAL INSTRUMENTS. 



All sound is caused by a vibration of the 

 air. These vibrations, although analogous to 

 those of the ether which are supposed to pro- 

 duce light and heat, are very much coarser, 

 and are quite within the cornprehension of 

 our senses. The thirty-second part of a 

 second is quite an appreciable interval of 

 time, and a musical note giving thirty-two 

 vibrations to a second is readily perceived bv 

 a normal ear. The opposite limit is quite 

 variable, depending upon individual peculiar- 

 ities, but 30,000 vibrations to a second may 

 be given as the average limit for the highest 

 perceptible note. 



The well-known experiment of striking a 

 bell in a vacuum, shows that the vibrations of 

 sound are transmitted by Jhe air itself, and 

 not by some more subtle medium, as with 

 heat, light, and electricity. 



The art of music consists in the production 

 of sounds of varying periods of vibration, at 

 such intervals and in such a manner as to 

 produce a pleasureable sensation upon the 

 ear. It would be beyond the scope of this 

 article to explain the complex mathematical 

 laws upon which the science of harmonv is 

 based, and we will only describe the princi- 

 ples upon which the instruments used to 

 produce musical notes are constructed. 



Nearly all musical instruments can be 

 divided into two classes — the stringed, and 

 wind. In the former the note is produced by 

 a vibrating string or cord, while in the latter 

 a column of air itself is set into vibration, and 

 takes the place of a string. 



The piano-forte is the most familiar exam- 

 ple of a stringed instrument. In this case, 

 each note is produced by a separate string, 

 which is carefully tuned to the right period of 



