A system of inorganic chemistry / by William Ramsay.

Date:
1891
Catalogue details

Licence: Public Domain Mark

Credit: A system of inorganic chemistry / by William Ramsay. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    36/740 (page 16)
    lecfcnres in the larger towns of England and Scotland. He inveis- tigated the relations between the temperature and pressure of liquids, the expansion of guses by heat, the solubility of gases in liquids, and other similar subjects ; but his discoveries in chemical theory were those which conferred on him a world-wide fame, and have exercised a lasting influence on the science. It was the habit of the analysts of that time, as it is now, to state their results in parts per 100. Thus Proust gives the following analyses of the compounds of copper and tin with oxygen:— Suboxide Protoxide Suboxide Protoxide of Copper. of Copper. of Tin. of Tin. Metal 86-2 80 87 78-4 Oxygen 13-8 20 13 21-6 100-0 100 100 100-0 It is obvious that, from inspection of the above numbers, no simple relation between the amounts of oxygen in the lower and higher oxides of coppei-, and in the lower and higher oxides of tin, is evident ; yet, if Proust had calculated the ratios, he might have guessed that the proportion of oxygen to copper in the second oxide is nearly double that in the first, viz., 13-8 : 21-6; and similarly with tin, 13 : 24. But still the analyses are not accurate enough to render this proportion self-evident, even if thus stated. It was during an investigation of two compounds of carbon with hydrogen, viz., marsh gas and defiant gas, or, as they are now named, methane and ethylene, and two compounds of carbon with oxygen, carbonic oxide and carbonic acid, or, as the latter o-as is now called, cai^bonic anhydride, that Dal ton was led to investigate the subject. He found that, if he reckoned the carbon in each the same, then marsh gas contains just twice as much hydrogen as olefianb gas; and carbonic acid just twice as much oxygen as carbonic oxide. He then considered the proportions of hydrogen and oxygen in water, and of hydrogen and nitrogen in ammonia, and having found, first, that when two elements combine with each other, they do so in constmit froportions hy weight, and second, that when two elements, A and B, form more than one com- pound with each other, they combine in simple mtdtiple proporlions, he deduced the following laws to account for these facts:— 1. Each element consists of precisely similar atoms of constant H: eight. 2. Chemical compounds consist of complex atoms,* which are * As the expression complex ntoa is a contradictory one, it -was aftcr- vnrds replaced by the word molecule, or little fiir.88 of atoms.