Search

Soucieux du maintien d'une prosperite economique basee sur des combustibles bon marche, l'A. se penche sur l'efficacite energetique et les economies d'energie. Il enonce le postulat selon lequel les economies d'energie ne diminuent pas la consommation mais au contraire, incitent a un usage accru. Il confirme cette hypothese a partir des progres economiques qui ont accompagne l'introduction de la machine a vapeur dans l'industrie en general et celle du fourneau de Siemens dans la siderurgie

It is remarkable that from the earliest times mechanical assistance has been employed in mathematical-computation. The use of pebbles, of the fingers, and of the abacus of the Greeks and Romans may be adduced as examples. Mathematicians have constantly delighted in devising me­chanical modes of calculations, as in the case of Napier’s bones, mechani­cal globes, slide rules, &c. Actual machines for performing difficult cal­culations have been designed or constructed at various times since the early part of the 17th century, by Pascal, Morland, Leibnitz, Gersten, Babbage, and Scheutz. In logic, on the contrary, we meet with a total absence of any actual mechanism, although logical works abound with expressions implying the need of such aid. The name of Aristotle’s logical treatises, the ‘Organon,' or Instrument , and many definitions of logic, clearly express this idea, which is also distinctly stated by Bacon in the second aphorism of his 'New Organon.’

Last autumn Prof. Strutt observed that the vapour of boron trichloride, when admitted into the afterglow of active nitrogen, developed a band spectrum, which he photographed with a quartz spectrograph of small dispersion. It seemed likely that this result might be interest in view of certain facts already established in connection with compoubds of the chemically related elements carbon and silicon, namely, that the interaction of carbon compounds and active nitrogen developed the cyanogen bands, and that the vapour of silicon nitride. Prof. Strutt, therefore, invited me to continue tthe boron experiments with a view to tracing the origin of the new system of bands, and ddetermining the numerical relations existing in it. The remarkable scarcity of boron lines lends additional interest to any new work on the spectroscopy of boron as a possible means of detecting hitherto unrecorded lines, or of eliminating others formerly attributed to boron. In this connection Sir William Crookes was shown that the boron lines are only three in number, via., λ 3461.50, λ 2497.83, λ 2496.89 (Rowland scale), and that some lines observed by Eder and Valenta and others were due not to boron but to impurities.