NEW YORK, SEPTEMBER 2, 1893. 



THE IMMEDIATE WORK IN CHEMICAL SCIENCE.' 



BY ALBERT B. PRESOOTT. 



A DIVISION of science has a work of its own to do, a work that 

 well might be done for its own sake, and still more must be done 

 in payment of what is due to the other divisions. Each section of 

 our association has its just task, and fidelity to this is an obliga- 

 tion to all the sections. Those engaged in any labor of science 

 owe a debt to the world at large, and can be called to give an ac- 

 count of what they are doing, and what they have to do, that the 

 truth may be shown on all sides. 



If it be in my power to make the annual address of this meeting 

 of any service at all to you who hear it — in your loyalty to the 

 association — I would bring before you some account of the work 

 that is wanted in the science of chemistry. Of what the chemists 

 have done in tlie past the arts of industry speak more plainly than 

 the words of any address. Of what chemists may do in the future 

 it would be quite in vain that I should venture to predict. But 

 of the nature of the work that is waiting in the chemical world 

 at the present time I desire to say what I can, and I desire to 

 speak in the interests of science in general. Tlie interests of sci- 

 ence, I am well assured, cannot be held indifferent to the interests 

 of the public at large. 



The Hidden Composition of Matter. 



It is not a small task to find out how the matter of the universe 

 is made. The task is hard, not because of the great quantity in 

 which matter exists, nor by reason of the multiplicity of the kinds 

 and compounds of matter, but rather from the obscurity under 

 which the actual composition of matter is hidden from man. The 

 physicists reach a conclusion that matter is an array of molecules, 

 little things, not so large as a millionth of a millimeter in size, 

 and the formation of these they leave to the work of the chemists. 

 The smallest ob.iects dealt with in science, their most distinct ac- 

 tivities become known only by the widest exercise of inductive 

 reason. 



The New World of Discovery. 



The realm of chemical action, the world within the molecules 

 of matter, the abode of the chemical atoms, is indeed a new world 

 and but little known. The speculative atoms of the ancients, 

 mere mechanical divisions, prefiguring the molecules of modern 

 science, yet gave no sign of the chemical atoms of this century, 

 nor any account of what happens in a chemical change. A new 

 field of knowledge was opened in 1774 by the discovery of oxygen, 

 and entered upon in 1804 by the publications of Dalton, a region 

 more remote and more difficult of access than was the unknown 

 continent toward which Christopher Columbus set his sails three 

 centuries earlier. The world within molecules has been open for 

 only a hundred years. The sixteenth century was not long 

 enough for an exploration of the continent of America, and the 

 nineteenth has not been long enough for the undertaking of the 

 chemists. When four centuries of search shall have been made in 

 the world of chemical formation, then science should be ready to 

 meet a congress of nations, to rejoice with the chemist upon the 

 issue of his task. 



It is well known that chemical labor has not been barren of re- 

 turns. The products of chemical action, numbering thousands of 

 thousands, have been sifted and measured and weighed. If you 

 ask what happens in a common chemical change you can obtain 



1 Address of the retiring president of tlie American Association at Eoches- 

 ter, August, 1892. 



direct answers. When coal burns in the air, how much oxygen 

 is used up can be stated with a degree of exactness true to the 

 first decimal of mass, perhaps to the second, yet questionable in 

 the third. How much carbonic acid is made can be told in weight 

 and in volume with approaching exactness. How much heat 

 this chemical action is worth, how much light, how much electro- 

 motive force, what train-load of cars it can carry, how long it 

 can make certain wheels go round, — for these questions chemists 

 and physicists are ready. With how many metals carbonic acid 

 will unite, how many ethers it can make into carbonates, into 

 what classes of molecules a certain larger fragment of carbonic 

 acid can be formed, — the incomplete records of these things already 

 run through a great many volumes. These carboxylio bodies are 

 open to productive studies, stimulated by various sorts of inquiry 

 and demands of life. Such have been the gatherings of research. 

 They have been slowly drawn into order, more slowly interpreted 

 in meaning. The advance has been constant, deliberate, some- 

 times in doubt, alivays persisting and gradually gaining firmer 

 ground. So chemistry has reached the period of definition. Its 

 guiding theory has come to be realized. 



The Central Truth of this Science. 



"The atomic theory" has more and more plainly appeared to 

 be the "Central and vital truth of chemical science. As a working 

 hypothesis it has directed abstruse research through difficult 

 ways to open accomplishment in vivid reality. As a system of 

 knowledge, it has more than kept pace with the rate of invention. 

 As a pholosophy, it is in touch with profound truth in physics, in 

 the mineral kingdom, and in the functions of living bodies. As 

 a language, it has been a necessity of man in dealing with chemi- 

 cal events. Something might have been done, no doubt, without 

 it, had it been possible to keep it out of the chemical mind. But 

 with a knowledge of the primary elements of matter, as held at 

 the beginning of this century, some theory of chemical atoms was 

 inevitable. And whatever theory might have been adopted, its 

 use in investigation would have drawn it with a certainty into the 

 essential features of the theory now established. It states the con- 

 stitution of matter in terms that stand for things as they are made. 

 The mathematician may choose the ratio of numerical notation, 

 whether the ratio of ten or some other. But the chemist must 

 find existing ratios of atomic and molecular mass, with such de- 

 gree of exactness as he can attain. Chemical notation, the index 

 of the atomic system, is imperfect, as science is incomplete. 

 However defective, it is the resultant of a multitude of facts. The 

 atomic theory has come to be more than facile language, more 

 than lucid classification, more than working hypothesis, it is the 

 definition of the known truth in the existence of matter. 



The chemical atom is known, however, for what it does, rather 

 than for what it is. It is known as a centre of action, a factor of 

 influence, an agent of power. It is identified by its responses, 

 and measured by its energies. Concealed as it is, each atom has 

 given proof of its own part in the structure of a molecule. Proofs 

 of position, not in space but in action, as related to other atoms, 

 have been obtained by a multitude of workers with the greatest 

 advantage. The arrangement of the atoms in space, however, is 

 another and later question, not involved in the general studies of 

 structure. But even this question has arisen upon its own chemi- 

 cal evidences for certain bodies, so that "the configuration" of 

 the molecule has become an object of active research. 



Known for what it does, the atom is not clearly known for what 

 it is. Chemists, at any rate, are concerned mainly wiih what can 

 be made out of atoms, not with what atoms can be made of. 

 Whatever they are, and by whatever force of motion it is that they 

 unite with each other, we define them by their effects. Through 

 their effects they are classified in the rank and file of the periodic 



