Objections to the Principle of Berzelius's Notation-Discus- Notation of Gerhardt-Ideas of Laurent-Reform of Canniz- zaro-Table of Atomic Weights-Law of Volumes-Present System of Atomic Weights deduced from the Law of Avo- gadro-Apparent Exceptions to the Law of Avogadro -Atomic Constitution of the Elements-New Atomic Weights in Harmony with the Law of Dulong and Petit- THE NEW SYSTEM OF ATOMIC WEIGHTS RESPECTS AND RENDERS EVIDENT THE ANALOGIES WHICH EXIST It agrees with Chemical Analogies-Ideas of Dumas-Mende- lejeff's Principle of Classification-New Atomic Weights in THE RELATIONS BETWEEN THE ATOMIC WEIGHTS OF THE at end THE ATOMIC THEORY. BOOK I. ATOMS. CHAPTER I. HISTORICAL INTRODUCTION-RICHTER-DALTON. THE hypothesis of atoms, put forward by the Greek philosophers, and revived in modern times by great thinkers, acquired a definite form at the beginning of this century. John Dalton was the first to apply it to the interpretation of the laws which he and Richter recognised as governing chemical combinations. Confirmed by the great discoveries of Gay-Lussac, Mitscherlich, Dulong and Petit, the hypothesis has assumed a definite form, connecting many various facts of a chemical and physical nature. Fundamentally it consists of modern ideas upon the constitution of matter. In common with correct ideas, it has grown with time, and nothing has as yet happened to stop its pro gress; but, in common with all fruitful ideas, it has been an instrument of progress even in the hands of its detractors. The latter are now few, and the hypothesis seems to make a firm stand against the regular opposition of some and the subtle attacks of others. In these pages we propose to discuss both its historical evolution and its present form, and we shall thus show the influence it has exercised upon the progress of science since the beginning of the century. Dalton revived the hypothesis of atoms to explain the fact that in chemical combinations elements unite in fixed proportions, and in certain cases in multiple proportions. He admitted that these proportions represent the relative weights of indivisible particles of the bodies, which particles are brought into contact and grouped by the fact of combination. This led to the consideration of atomic weights, and the idea of representing the composition of bodies by symbols which indicate both the nature and the number of these particles and the proportion of the elements entering into combination. We have here two things which must not be confounded—facts and an hypothesis. We shall retain the hypothesis as long as it gives a faithful interpretation of facts, and enables us to group them, to connect them together, and to anticipate fresh ones -as long, in fact, as it proves fertile. An hypothesis thus formed rises to the rank of a theory. We shall endeavour to show, in demonstrating its origin, progress, and results, that this is the case with Dalton's conception. |