Treatise on general and industrial inorganic chemistry / by Etore Molinari ; third revised and amplified Italian edition translated by Ernest Feilman.
- Ettore Molinari
- Date:
- 1912
Licence: In copyright
Credit: Treatise on general and industrial inorganic chemistry / by Etore Molinari ; third revised and amplified Italian edition translated by Ernest Feilman. Source: Wellcome Collection.
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![and if tl'.o c vil;rationr5 oxcocd sixlec'ii }K'r ;jccc:i(l \vo Vviil ob.sorvc* a sliglit noto ; as thè vibrations «aro cradnally inoì’oasod in froqnoncy up to 40,000 per rocoikI, wo will ascend tlio scalo of all notes froin thè lowost to thè liighost and slirillost ; wo bave thns obtainod onorgy of sonnd. If tho nninbor of vibrations is furthor incroasod thoy aro no longor porc('ivod by tho oar, but on approaching tho piato with thè hand it will ho obsorvod that it is warm ; wo aro obtaining thormal enorgy. If thè frcqnency increases stili fnrthor thè toniperatnro rises, and when thè vibrations bave attainod a frequoney of 400 billions por second thè piate bccomes red-hot and gradually more liiminous ; we bave now Inininons energy, If thè froqucncy of thè vibrations exceeds 800 billions por second our eyes are no longcr able to pcrccive them, but if a pliotographic p'ate containing silvcr salts is exposed to these rays,it isaffccted ; wc bave rcached Chemical energy, and by proceeding fnrthor it is theorctically possible to arrivo at elcctrical enorgy, &c. The tran.sformations of Idnetic energy aro to-day of thè greatest importance, and we soe evory day thousands of practical examples of thè manner in which it may pass from ono forni to another. Anotlicr cxperiinent which givos some idea of thè transformation of mcchanical energy into thormal and luminous energy is thè following: On throwing a picco of sodiinn into water it floats and travels rapidly over thè surface, devcloping hydrogen gas, but if a piece of fìlter-papor is placcd on tho surface of thè water and tho sodium is placcd on this, its motion is prevented ; thè energy produced, which was in thè prcvious case manifested as energy of motion, is now transformod into thermal energy, and thè sodium is hoated and catches tire, giving a luminous flame and then an explosion On striking a match thè mechanical energy is transformed into thermal energy and thè match is lit, transforming thormal and Chemical energy into luminous energy. But we are able to observe thè most beautiful and marvellous examples of thè trans- formations and indestructibility of energy every day in thè case of thè solar beat. This inexhaustible source of energy, which is givenotf bythe sun without sensible diminution, is not lost. The heat which reaches thè earth and is distributed over scas and continents. causing temperature disturbances at various points, also creates thè acrial ciurents of thè terrestrial atmosphcrc, and thè energy thus formed is utilised in thè sails of ships and of windmills. This beneficent heat also evaporates thè water of seas, lakes, and rivers, transporting thè water particles to greater altitudes and thus accumulating potential energ5% which is again liberated when thè vapour condenses to forni rain or show, and then doscends in watercourses from higher to lower regions and thè sca, returning thè potential energy to nature in thè forni of mechanical, electrical, and thermal energy, nioving thè wheels of niills and tiirbines, which actuate dynamos giving motion, light, heat, and olcctricity in sudi a nianm^r that thè balance of nature is unintorruptedly niaintained. This extcnds to all life, minerai, vegetable, and animai, in a marvellous harmony of simplc and coni- })licated transformations, to thè nutrition of plaiits and animals, to human vitality. to that of thè thinker and thè genius. In thè entire universe, whatever changes it is undergoing, has undergono, or will undergo n thè future, thcrc will always at cadi instant be found exactly thè sanie unaltorcd sum of kinetic and potential energy. Helmholtz calculatcd that of thè potential and mechanical energy which originally existed in our own solar System onlythe fom hundred and tifty- fourtli part stili remains, thè rest having been dispersed and transformod into heat, light, &c., during thè passagc from thè nebuloiis stage to that of consistont nuclei ; but none of this energy is lost to thè universe. wliioh worc tlio moro intonso and rapid tho higlior tho toinporatnrc. Tho nndnlatnry tlioory had alroady bocn ii])hol<l hyjloolco (HifiO), llny<;hons, and linh'r (1707-1783) in ordcr to oxplain liiininous idionoinona ; bnt nntil 3800 Ilio ojiposito theory of Newton, that is, tho onianation tlioory, was ^onorally nphold. In 1810 Davyhimsolf liad acooptod hnniford’s tlioory of hoat, Init in tho caso of lij-tlit hi' doolarod himsolf a followor of Ni'wton’s hypo- thosis of omission (1042-1727). fn tho nii'antinio 'I'. Voung and Wollaston fonnd thoinsolves ohligod to aliandoli tho l'inission theory; Init l<’rosnol was lirst alile to show that Ilio oinission Ihoory was orronoons hy roplacin;i it liy his own vory lirilliaiit hypothosis, which moro satisfadnrily oxiilaiiu'd tlioso iniportant physioal iih.onomona, namely, tho liypothcsis of a oontimions olastic niodinm which ]ionotratod all liodios and thè entire nnivorso. l’oisson (1781-1840) f;avo oonoroto and ri^'orons forni to this hypol lu'sis, imaj'inin!' tho olastic nnalinin to ho oomposod of vory small otheroal partiolos, viliratiiiir intonsoly, hy which iiioans ho was alilo to ox]ilain, and niatho- matioally domonstrato, niany physioal phonomona which wno otliorwiso inoxplieahlo. Aftorwards it was possihlo forClansins (1807) to niatlioniatioally lay tho fonndalion of his hrilliant meohanioal tlioory of In'at. Jt is oon- vonicnt to record horo that to-tlay, aftor fnrthor stndy of olootrioal phonomcna, thè idea of an otlii'r snhdividod into minimal ])articlos has heon ahandonod, that is, tho tlioory of its discontinnity is now exolndod ; thè stndy of cathode rays and of radio-aotivity has led to a siiooios of return to thè theory of material emanation, which has not yet found a clear cxplan.ation, hy the generai laws accepted to-day.](https://iiif.wellcomecollection.org/image/b28134187_0030.jp2/full/800%2C/0/default.jpg)
