5IO 



POPULAR SCIENCE MONTHLY. 



flame, becoming plastic enough for 

 manipulation only above the melting 

 point of platinum. In preparing tubes 

 the first step is a rod, which is made by 

 fusing small pieces of silica together, 

 one after another. This rough rod is 

 then re-heated and drawn out into finer 

 rods about a millimeter in diameter. 

 These rods are then bound around a 

 thick platinum wire and heated till 

 they adhere to each other forming a 

 tube which can then be drawn out and 

 worked much as a tube of glass. By 

 blowing a small bulb on the end of the 

 tube, surrounding it with a ring of 

 silica, re-heating and blowing, the tube 

 can be lengthened or the bulb enlarged 

 at will. From this starting point it is 

 possible to make quite complicated 

 apparatus. 



An examination of vitrified silica re- 

 veals several properties which give it a 

 peculiar value for many purposes. Its 

 melting point is so high that a plati- 

 num wire imbedded in a thick silica 

 tube can be fused so as to flow out, be- 

 fore the tube softens sufficiently to lose 

 its shape. Its coefficient of expansion 

 is far less than that of any similar sub- 

 stance, being only one- seventeenth that 

 of platinum. This expansion is very 

 regular up to 1,000", when it dimin- 

 ishes rapidly up to 1,200° and from 

 this point on it contracts. Up to 1,500° 

 it remains practically solid. In its ex- 

 pansion it difi"ers very markedly from 

 quartz, which not only has a much 

 higher coefficient of expansion, but 

 which at 570° expands so rapidly that 

 it is shattered. A rod of vitrified silica 

 can be heated white hot and then imme- 

 diately plunged into liquid air with- 

 out sufi"ering injury, indeed it gains in 

 elasticity when thus treated. These 

 properties promise to be of great value 

 in the construction of thermometers. 

 Its transparency to the ultra-violet 

 rays of the spectrum will give it a de- 

 cided advantage over glass in spectro- 

 scopic work. It is also interesting to 

 note that tubes of silica can be heated 

 sufficiently high for nitrogen and 



oxygen to unite directly on passing 

 through them. It is, on the other hand, 

 slightly permeable to hydrogen at a 

 temperature of 1,000°C. Altogether 

 vitrified silica offers an interesting field 

 of development in the immediate 

 future. 



TWO REMARKS CONCERNING 

 THE 'MONTHLY.' 



The following paragraph is repro- 

 duced from the 'Electrical World,' as a 

 favorable occasion for two remarks 

 that it has for some time seemed de- 

 sirable to make: 



In the current number of our 

 esteemed contemporary, the Poptjlar 

 Science Monthly, which is, alas! 

 more popular than scientific in the 

 single particular that its pages lie 

 largely sealed from mortal eye until 

 separated by that anachronous atrocity 

 — the paperknife — appears a delightful 

 article by Professor J. J. Thomson, 

 'On Bodies Smaller than Atoms,' an 

 abstract of which appears in the 

 Digest. It is a commentary upon the 

 spread of technical education that a 

 paper on this most abstruse subject, 

 and actually containing some little 

 algebra, should find the light of day 

 in popularized literature, and awake a 

 gleam of recognition from the eyes of 

 many who are not scientists. Twenty 

 years ago such an article on such a 

 subject would have lain on popular 

 benches as caviare to the multitude. It 

 is difficult to say which commands our 

 admiration the more — the article itself, 

 or the fact that the great world should 

 be capable of admitting it into semi- 

 popular literature. Either considera- 

 tion presents a triumph, the one over 

 inanimate, the other animate, nature. 



The first remark concerns trimming 

 the pages of the Monthly. It appears 

 from the correspondence of the publi- 

 cation department that to trim or not 

 to trim is a burning question. An 

 'anachronous atrocity' is pretty strong 

 language, but it seems to define a 

 widespread creed. Some people ap- 

 parently do not know that there is a 

 good scientific reason for not trimming 

 the edges, namely, that a magazine or 

 book that has been trimmed cannot be 

 ; properly bound afterwards. Conse- 



