656 > REPORT — 1895. 



The following Papers and Eeports were read : — 



1. A New View of the Genesis of Dalton's Atomic Theory, derived from 

 ' Original Manuscripts. By Sir H. E. RoscoE, F.E.S., and Arthur 

 Harden. 



A number of previously unknown manuscript volumes in Dalton's writing have 

 been found in the library of the Manchester Literary and Philosophical Society. 

 These consist of laboratory note-books containing the record of Dalton's practical 

 work from the year 1802 onwards, and the notes used by him for some of the 

 lectures delivered at the Royal Institution, London, in 1810. 



The examination of these volumes has cast au unexpected light on the genesis 

 of the atomic theory, and the relation in which that theory stands to the law of 

 combination in multiple proportions. Neither in Dalton's published papers, nor in 

 the ' New System,' was any satisfactory account to be found of the genesis of his 

 theories and hence the question as to whether the atomic theory was founded on 

 an experimental knowledge of the law of combination, or whether Dalton arrived 

 at this law as a necessary consequence of the atomic theory of matter, was not 

 to be gathered from his own writings. The balance of evidence derived from 

 these newly discovered documents is strongly in favour of the statement made in 

 London by Dalton himself, in 1810, that he was led to adopt the atomic theory of 

 chemistry in the first instance by purely physical considerations, in opposition to the 

 view, hitherto held by chemists, that the discovery by Dalton of the fact of com- 

 bination in multiple proportions led him to devise the atomic theory as an 

 explanation. 



2 Report on the Teaching of Science in Elementary Schools. 

 See Reports, p. 228. 



3. The Action of Nitric Oxide on some Metallic Salts. 

 By H. A. AuDEN, B.Sc, and Q. J. Fowlee, M.Sc. 



The experiments here recorded are part of a systematic investigation into the 

 conditions of stability of the oxides of nitrogen. They are by no means complete, 

 but the results so far obtained appear to be of sufficient interest to warrant a 



preliminary notice. . j- j rp, 



The reactions of nitric oxide have so far alone been studied, i he gas was 

 prepared by Emich's method— viz., the interaction of sodium nitrite, strong 

 sulphuric acid, and mercurv. The mixture was kept in continual agitation by a 

 specially contrived stirrer, worked by a turbine. In this way a regular stream of 

 gas is obtained, which analysis showed to be of a high state of purjty. 



In order to study the action of nitric oxide upon the salts selected a weighed 

 amount of the salt was placed in a boat contamed in a Lotbar Meyer constant 

 temperature furnace. By means of a thermostat, also devised by Lothar Meyer^ 

 the temperature can be kept constant to within one degree. Temperatures above 

 the rano-e of an ordinary instrument were measured by means of a high tempera- 

 ture thermometer, constructed by Max Kaehler and Martini, of Berhn, which 

 would give accurate readings to over 400°. _ _ ■, , , 



The salt was heated gi-adually in a stream of nitric oxide, and the phenomena 

 noted as the temperature rose. The salt was weighed at different intervals of 

 temperature and time. Thus it was possible to tell at what temperature reaction 

 beo-an and at what point it attained a maximum velocity. 



''So far oxv-salts have been chiefly studied. It was thought that by comparing 

 their behaviour under the above conditions some light might be thrown on their 

 stability, and thence on their constitution. 



One or two oxides were first examined, the results agreeing with those pt 

 Sabatier and Senderens ; e.g., PbO^ forma a basic nitrate of lead : when heated m 



