598 



SCIENTIFIC NEWS. 



[June 22, i8 



CORRESPONDENCE. 



The Editor does not hold himself responsible for opinions expressed 

 by his correspondents, nor can he take notice of anonymous com- 

 munications. All letters 7nust be accompanied by the naine and 

 address of the writer, not necessarily for publication, but as a 

 guarantee of good faith. 



A CIRCLE PROBLEM. 



Permit me to make a few remarks on a letter appearing in 

 yom- last issue, and entitled "A Circle Problem." The 

 problem which your correspondent proposes is ; " How much 

 farther does the outer handle of one of the carriages of an 

 ' inner circle ' train travel in one journey than the inner 

 handle, the circumference of the circle being 13 J miles, and 

 the handles being 9 ft. apart? " He goes on to say " Reduce 

 the circumference to feet, =63,360, divide by 3-14159 to find 

 the diameter, = 20,l68-i ft. Take this as the distance travelled 

 by the inner handle." Now, 63,360 is the number of feet in 

 12 miles, not in 13I miles, which = 7i,2So ft. ; and the word 

 this, evidently, from the context, means 20,i6S-i ft., which is 

 the diameter of the circle, and, therefore, cannot possibly be 

 "the distance travelled by the inner handle." Again, your 

 correspondent says : " A little reflection shows that the cir- 

 cumference of the circles has nothing to do with the problem, 

 UNLESS they are several thojtsand miles in diameter. The 

 difference will always be the circumference of a circle 18 ft. 

 in diameter." The latter sentence contradicts the former, 

 and in the last paragraph of his letter your correspondent 

 proves that the circumference of the circles has nothing to do 

 with the problem, although the circles are several thousand 

 miles in diameter. How much more interesting to many 

 readers of Scientific News would the problem have been 

 had " A. P. T." shown why the difference in the distance 

 travelled by the inner and outer handles of the carriage is 

 always the same, no matter how great may be the circle they 

 perform. Perhaps he will do this in a subsequent issue of 

 your valuable paper. If not, with your permission, I will 

 make an attempt to explain it. 



There is one more error in " A. P. T.'s " letter that I would 

 like to mention. In the last paragraph he says, " If the 

 track encircles the earth the diameter would be abo7it 25,000 

 miles in diametet'." Who is responsible for this statement ? — 

 whether writer, pen, or printer I cannot say, and I leave it 

 to my fellow-readers to make what they can of it. 



Apologising for encroaching on your valuable space, 



KUKLOS. 



THE QUANTITY OF LIFE. 

 Permit me to point out an in portant difference between 

 life and all the various modifications of energy met with in 

 non-vitalised matter. We can measure gravitation, heat, 

 light, electricity, magnetism, and chemical force we can dis- 

 cuss them quantitatively and can examine their numerical 

 relations ; but can we do the same with life ? Can we say 

 that there is more life in an adult man than in a young 

 child, in a healthy man than an invalid, in an elephant than in 

 a mouse, in a vertebrate animal than in an insect or a moUusk, 

 in an animal than in a tree ? Are we even prepared to say 

 whether the idea of quantity is applicable to life at all ? 

 _ J. W. S. 



Technical Education. — Dr. Gladstone, F.R.S., in giving 

 evidence before a special committee of the London School 

 Board, submitted the following statement : — " Professor 

 Sylvanus Thompson told me that the only elementary school 

 in London from which the Finsbury College could draw 

 youths qualified for the technical classes was that of St. 

 Thomas Charterhouse, where a good deal of scientific 

 instruction is given and the boys are encouraged to make 

 their own apparatus." Mr. Edward Bond, Assistant Charity 

 Commissioner, instanced only three primary schools in 

 England, viz., the higher primary schools of Manchester and 

 Sheffield and St. Thomas Charterhouse, London, as giving 

 an education calculated to develop intelligent artisans. 

 Considering what is spent on education in this country, 

 better results ought fairly to be expected. 



RECENT INVENTIONS. 



The following list has been compiled esfecially for the Scientific 

 News by Messrs. W. P. Thompson and Boult, Patent Agents, of 

 323, High Holborn, London, W.C ; Newcastle Chambers, A^igel 

 Row, Nottingham ; Ducie Buildings, Bank Street, Manchester; 

 and 6, Lord Street, Liverpool. 



Extinguishing Oil Lamps. — An extinguisher for oil 

 lamps has been patented by Mr. P. R. Baker, ol 

 Birmingham. The extinguisher consists of a strip of 

 metal, which is fastened to the bottom of the wick tube 

 through which it passes, and is bent over to form a cap. 

 The piece is normally held back, but upon lowering the 

 wick the cap springs over it and extinguishes the flame. 



Car-Coupling.— A car-coupling has been patented by 

 M. G. E. Ribault, which consists in attaching to each car 

 a sleeve with a bell mouth, and opposite to it on the 

 other car is a looped bar, which enters the sleeve, and 

 it is then fastened by a catch which drops automatically. 

 When it is desired to uncouple the cars the catches are 

 raised and are held in position by a spring, and the act 

 is accomplished. 



Lamp Trimmer. — An improved lamp-trimmer has been 

 patented by Mr. E. Bailer, and consists in constructing 

 it so that the parts cut off the wick are prevented from 

 falling into the burner or lamp when the same is being 

 trimmed. A box is placed on the trimmer, and the parts 

 cut off are forced into it by means of a guard. The box 

 being kept closed by spring studs on the arms or handles 

 of the trimm.er when not in use. 



Lighting Matches. — A device for lighting matches 

 has been patented by Mr. T. E. Ware, of Bristol. It 

 consists of a tube having a tapering end partially closed 

 by serrate(J springs, and provided with a longitudinal slit 

 for the insertion of a match. The match, which is laid 

 with its head towards the end, is ignited by being 

 partially ejected by a plunger, and is then held by the 

 springs while used for lighting purposes. 



Incandescent Gas Lamp. — An incandescent gas lamp 

 has been patented by Mr. H. Schlichter, of 95, Milton 

 Street, London. According to this invention, gas and air 

 are conducted by separate pipes to the chamber, the 

 mixture issuing by the burner. The issuing gas is 

 ignited by impinging upon spongy platinum, and heats a 

 platinum wire or strip. The flame may then be extin- j 

 guished ; the mixed gas and air impinging upon the plati- 

 num wire causes it to remain incandescent and emit light. 



.Window Fastener. — An improved fastener for win- 

 dows has been patented by Messrs. G. and S. D. Duffy, 

 and consists of a brass screw which is attached to the lower 

 sash, and a socket attached to the upper one. Inside the 

 brass screw is a hardened steel pin, which is loose, and 

 thus, should the outer screw of brass be cut, the said steel 

 pin would revolve, being loose, inside the outer screw, 

 and consequently could not be cut through. The fastenei 

 also permits of the sashes being screwed tightly together 

 and consequently prevents them rattling. 



Speed of Vessels. — An apparatus for indicating the« 

 speed of a vessel and the distance run has been patented 

 by Mr. C. Sperry, and consists of an instrument operated 

 by the varying pressures in tubes projecting from the 

 bottom of the vessel, produced by the resistance of the 



