286 



THE POPULAR SCIENCE MONTHLY. 



somewhat tedious, but the results fully repay 

 the worker. By means of these methods 

 steel has been found to contain five main 

 constituents: Pure iron, ferrite\ carbide of 

 iron, cementite; sorbite, of uncertain compo- 

 sition ; martensite and froosfife; the latter 

 marks the transition of soft iron into hard- 

 ened steel. Sorbite, f roostite, and martensite 

 appear to be solidified solutions of various 

 forms of carbon in divers forms of iron, for 

 it seems clear that metallographic work on 

 steel brings into prominence the existence 

 of allotropic forms of iron. An exhaustive 

 monograph on the progress of micro-metal- 

 lography during the past ten years, by M. F. 

 Osmond, may be found in the Bulletin de la 

 Societe d' Encouragement, vol. x, p. 480, 1895. 



Audibility of Fog-horn Signals. Some 

 time ago there appeared a description of 

 some experiments which went to prove that 

 around each siren there is a zone, about one 

 and a half nautical miles broad, within which 

 fog signals can not be heard, although they 

 are distinctly heard outside that zone. These 

 statements have been recently confirmed by 

 a series of experiments which are noted in 

 Nature. In one of these the vessel steamed 

 with the wind straight toward the lightship 

 from a distance of four and a half nautical 

 miles. At a distance of two miles and three 

 quarters the sound became faintly audible, 

 and suddenly increased in loudness at two 

 miles and a half, retaining the same inten- 

 sity up to two miles distance. From one and 

 three quarters to one and a half mile the note 

 was scarcely audible, but then it immediately 

 increased to such an extent that it appeared 

 to originate in the immediate neighborhood 

 of the vessel. The steamer at this point re- 

 versed its course, and the fluctuation over this 

 part of the course was found to be the same, 

 except that it was even more strongly marked. 

 The vessel was again reversed, and at half a 

 mile the sound disappeared entirely, to reap- 

 pear at a quarter of a mile from the light- 

 ship; after which it gradually and steadily 

 increased in intensity until the latter was 

 reached. 



The Ideals of Modern Medicine. We 



take the following from President Sir T. 

 Russell Reynolds's address before the recent 

 meeting of the British Medical Association 



in London: "The outcome of what I have 

 been saying is this : that the scattered frag- 

 ments of knowledge and guesses at truth of 

 many years have been gathered into a focus 

 during the past twenty -five years ; that the 

 vegetable life extracting from the mineral 

 world the materials it needs for growth and 

 production of powerful agencies for good in 

 the form of food and medicines, and for evil 

 in the form of poisons, has given itself up 

 to the growth of animal life, with its much 

 more complex organs, and for cure of ills 

 once thought beyond the reach of human 

 aid ; but that, thanks to man's scientific ar- 

 dor and industry, it has again shown itself 

 to be our servant, our helper, and our pro- 

 tector. These are not dreams of the study, 

 they are facts of the laboratory and of daily 

 life ; and in using that word ' life ' again, I 

 must endeavor to emphasize still more forci- 

 bly upon you my urgent belief that it is to 

 living agencies and their employment that 

 we must look for help in the care of infancy, 

 the conduct of education moral, mental, 

 and physical the training up of character, 

 as well as of limbs ; that it is the guidance 

 of living functions, in the choice of living 

 occupations, be they either of hard work or 

 of amusement. It is to these we must ap- 

 peal if we would see the mens sana in corpore 

 sano ; and then it will be to these that we 

 may confidently look for help, when the in- 

 roads of age or of disease are at hand, often 

 to cure us of our trouble ; or if not, to give 

 us rest and peace." 



City GOTernment. The corporation of the 

 city of London is one of the most ancient 

 bodies in England, and its record shows a 

 constant succession of capable men and a 

 uniform policy. It was in existence before 

 Parliament, and it has seen the downfall of 

 more than one royal house. The secret of 

 its success has lain in the fact that muni- 

 cipal dignity has always been confided to the 

 hands of men of business, who had shown 

 their capacity to manage private affairs of 

 great magnitude before they were intrusted 

 with those of their neighbors. Their training 

 had been such as to remove them as far from 

 the hide-bound conservatism of the official 

 as from the destructive reforming energy 

 of the professional politician. As an in- 

 stance of the methods employed may be 



