Clement and Desormes

Although Courtois discovered iodine in 1811, the announcement by Clement and Desormes was not made until two years later. Therefore, the centenary was observed in 1913. 

Historical.—This process had its origin in the early preparation of sulphuric acid by the oxidation of sulphur dioxide with nitric acid, for which operation lead chambers were first introduced in 1746 by Roebuck of Birmingham. In 1793 Clement and Desormes showed that under proper conditions the nitric acid aids the oxidation, which is in the main effected by atmospheric oxygen, and the injection of steam having already been introduced in 1774 by de la Follie, the basal chemical process was much the same as to-day. Gay-Lussac s tower was first suggested by that chemist in 1827 and was first used in 1835, being introduced into Britain in 1844. J. Glover constructed his first tower at Newcastle in 1861. 

According to Chugaev, the study of Clement and Desorm was the second piece of evidence in favour of the possible existence of a new class of reactions (catalytic). The first piece was the Dutch chemists study of the decomposition of ethyl alcohol to water and ethylene in the presence of silica or alumina. 

As a result of inexact experiments, Creighton and Southern (1803) supposed that the latent heat of steam, 4, was independent of temperature, whilst Watt supposed that the total heat, was independent of temperature. Experiments of Clement and Desormes seemed to confirm Watt s assumption, which was generally adopted by engineers and called JVatt s law. Both laws were shown to be incorrect by the careful experiments of Regnault, who found... 

Show that this is essentially the basis of the Clement and Desormes method for determining 7 for gases [equation (10.11)]. 

Iodine was the second halogen to be discovered. It was first observed by Courtois, a manufacturer of nitre, in 181 r, but this was not announced until two years later by Clement and Desormes. Like so many other important discoveries that of iodine is what is popularly called accidental . That is to say it was not the result of a specific search for the element, but of a chance observation by an intelligent observer. 

Thomson says this notice was written by Gay-Lussac. Cuvier says Clement and Desormes showed the substance to PAcademie , and mentions the detonating powder discovered by Courtois in 1811 by the action of ammonia on Piode , of which he told Clement and Desormes only in 1813. 

Nicolas Clement (Dijon, 12 January 1779-Paris, 21 November 1841) went to Paris as clerk to an uncle, a notary. He studied in libraries and turned to science. With the support of Montgolfier and Guyton de Morveau he studied chemistry, and was Guyton s assistant at the ficole Polytechnique. He became professor at the Conservatoire des Arts et Metiers. Having won a lottery he married the daughter of Charles Bernard Desormes (Dijon, 3 June 1777-Verberie, Dept. Oise, 30 August 1862), who had been assistant to Guyton, and he took the name Clement-Desormes (hence some accounts make Clement and Desormes the same person). Clement and Desormes owned chemical works at Verberie. ... 

Faraday in his diary says Ampere, Clement, and Desormes came this morning [23 November 1813] to show Sir H. Davy a new substance, discovered, about two years ago, by M. Courtois, saltpetre manufacturer. The process by which it is obtained is not yet publicly known. It is said to be procured from a very common substance, and in considerable quantities . Very little information would seem to have been given to Davy, who at first (says Faraday) thought it was a compound of chlorine and an unknown body, although the entry for the same day says Davy now thinks it contains no chlorine . On I December, Faraday says, Davy had made many experiments on it with his travelling apparatus M. Clement has lately read a paper on it... in which he says it is procured from the ashes of sea-weeds by lixiviation and treatment with sulphuric acid. He conceives it to be a new supporter of combustion. On 3 December, Davy was working on it in Chevreul s laboratory and on ii December he concluded that as yet it must be considered as a simple body . 

Dalton, who called it carbonic oxide , found that 100 vols. required 47 of oxygen and gave 94 of carbonic acid, saying I always find the oxygen fully equal to half the carbonic acid, whether fired over mercury or water. That the oxygen in carbonic acid was found to be just double of that in the carbonic oxide for a given quantity of carbone by Clement and Desormes is noted by Dalton, who adds This most striking circumstance seems to have wholly escaped their notice. ... 

On 27 June 1800, Dalton read Experiments and Observations on the Heat and Cold produced by the Mechanical Condensation and Rarefaction of Air. Joule (a pupil of Dalton) says that Dalton ascertained that about 50 of heat are evolved when air is compressed to one-half its original bulk and that, on the other hand, 50 are absorbed by a corresponding rarefaction and this result can be inferred from what Dalton says, although it is not explicitly stated. The method (of adiabatic expansion) was afterwards adapted by Clement and Desormes to the determination of the ratio of specific heats of a gas. ... 

Carbon monoxide CO, is a gas that develops in each incomplete combustion of carbon-containing compounds (e.g. coal, petroleum, natural gas). Carbon monoxide was discovered by Lasonne in 1776 when glowing coal with zinc oxide, and in 1796 by Priestley when glowing coal with hammer blow (Fe304) [5.10]. Originally, the gas had been interpreted as hydrocarbon, in 1801 Clement and Desormes determined the chemical composition. In 1877, CO was liquefied for the first time by I. Cailletet. The carbon monoxide amounts of the earths atmosphere are for the most part based on the bacterial emission of CO in the soil and the sea. 

At that time, acid was still being made in batches and no air was added to the lead house during reaction. By 1793 Clement and Desormes had suggested that the continuous addition of air would improve reaction, and in 1806 they defined the action of niter, which was clearly essential to the process ... 

Clement and Desormes were also the first to observe the formation of chamber crystals that evolved nitric oxide and formed sulfuric acid when added to water. The nitric oxide was then available for recycling. 

Clement and Desormes 1807 1814 St RoUox, Scotland Continuous flow of air limited amount of KNO3 required. Continuous sulAir burning— steam and air flowing through lead chambers. Confirmed air was main (90%) oxidant and KN03 only an intermediate. 

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