# Popular Science Monthly/Volume 64/March 1904/The Progress of Science

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IMMANUEL KANT.
The centenary of the death of Kant was commemorated on February 12. There was a special celebration at Königsberg, where the philosopher spent his whole life; a monument is planned for Berlin, and a Kant Society has been formed in Germany. It would probably be difficult for most readers of a scientific journal to explain why Kant is one of the great men of the world, and next to Aristotle the most honored philosopher. In the preface to his 'Kritik der reinen Vernunft' Kant expressed his own view of the service he hoped to accomplish in the following words: "In metaphysical speculation it has always been assumed that all our knowledge must conform to objects; but all attempts from this point of view to extend our knowledge of objects a priori by means of conception have ended in failure. It is well to ask, therefore, whether greater progress may not be made by supposing that objects must conform to our knowledge. This would clearly agree better with the desired possibility of such an a priori knowledge of objects that could establish something about them before they are presented. Our suggestion is similar to that of Copernicus in astronomy, who, finding it impossible to explain the movements of the heavenly bodies on the supposition that they turned round the spectator, tried whether he might not succeed better by supposing the spectator to revolve and the stars to remain at rest. Let us make a similar experiment in metaphysics with perception."
Kant's rather remarkable lack of appreciation of the work of his predecessors led him to emphasize unduly the novelty of his own point of view. Yet subsequent philosophers have tended quite generally to regard him as its most representative exponent. And he forced the issue with such energy as to make himself the most prominent figure in the philosophy of the last century. He asserted repeatedly that we do possess knowledge of objects which is universal and necessary, and he asserted with no less frequency that in all such cases our knowledge has not conformed to objects, but objects have conformed to the necessities of thought. Just because we find that we must think of objects in a certain way, we must admit that this necessity springs from thought itself. In spite of the fact that this assumption is far from self-evident, Kant succeeded in imposing it upon his time with remarkable success. The philosophy of the nineteenth century witnessed as a result many noteworthy attempts to determine what reality must be by reference to the necessities of thought alone. The absurdities of Schelling and the subtleties of Hegel mark, perhaps, the extremes of this tendency.
But the significance of Kant is not seen only in this new inspiration given to the attempt to determine, not what reality is, but what it must be. For his philosophy had its negative side, which contained an equally important emphasis. Just because what we must think is due to the necessities of thought, we have no right, he urged, to extend the results of such thinking beyond thought itself and so pass to things as they are. Exterior to thought, beyond its controlling influence, they escape us utterly. The significance of this important limitation Kant exhibited most crucially when he criticized all attempts of speculative thinking to establish the ​existence of God, freedom and immortality, the three things with which, as he viewed it, metaphysics is most concerned. Here thought finds itself completely baffled and confronted by contradictory possibilities for which there appears equally valid evidence.
Thus metaphysics would appear to be an impossible science—a result in strange contrast with the successive systems of metaphysics which the positive aspect of his work called into being. Kant remained stubbornly true to his conviction that the necessities of thought set their own impassable limits. Agnosticism has thus found
him an able support, and Heine could say of the 'Kritik,' 'This book is the sword with which, in Germany, theism was decapitated.'
Kant, however, would find in practical life and particularly in moral life a way of transcending the limits
of speculative thinking. In his writings on morality and religion he claims that the necessities of practise have also a determining influence on the content of philosophy. Man's morality presupposes as conditions necessary to its existence the very things—God, freedom and immortality—which man's reason can not attain, and the existen ​of morality itself becomes, therefore, the guarantee of their existence. Practise thus gives what speculation fails to give. So after all the theologian could take courage from the Kantian philosophy, and the pragmatism of to-day could find a basis in the searching criticism of the Königsberg professor. The significance of Kant for modern philosophy has thus been wide and varied. He has been at once an inspiration and a check to free speculation, and also a source of renewed progress in moral and religious inquiry. Yet, it must be admitted that his importance has waned considerably in recent years. His central idea that there are necessities of thought and practise which of themselves significantly determine the content of our knowledge and belief has come to lack its authoritative tone. This has been brought about not so much by direct refutation as by the steady advance in stability of scientific knowledge, which insists that we can be really compelled only by the exigencies of the things with which we deal. Kant in his early years was no mean scientist. Indeed he thought that his philosophy could give to science its only stable basis and its only correct interpretation. The result is in striking contrast with his conviction.
RECENT PROGRESS IN THE STUDY OF RADIOACTIVITY.
The dream of the alchemists had without doubt a strong philosophical foundation, and although the desire to accomplish transmutations of the elements has lost all power as an incentive to the study of natural phenomena, one can not help noticing the small amount of reverence modern physics has for the identity of the atom of a chemical element. The electronic theory of matter, well set forth by Sir Oliver Lodge in his Romanes lecture at Oxford, which was published in this magazine last August, holds that there is no more difference between the atoms of the different elements than between houses of different shapes and sizes, but built of the same kind of bricks, the little electrons being the bricks of which the atoms are built, although the structure of an atom is more like that of a planetary system than that of a house. Confidence in the stability of this structure in the case of ordinary atoms has not been shown to be misplaced, but in the case of the radioactive substances—elements they are by the usual tests—evidence of atomic disintegration continues to accumulate. Their radiations consist chiefly of projected particles, far smaller than the atoms of the radioactive elements, and, as Professor Rutherford and Mr. Soddy have shown, the radioactive matter passes successively through a series of unstable forms. The final product of this atomic disintegration must be stable and therefore not radioactive, and since the gas helium is found in all radioactive minerals it is suggested that helium is one of the stable residues left by the heavy and unstable radioactive atoms.
During the past summer Professor Ramsay, the discoverer of terrestrial helium, and Mr. Soddy followed up this suggestion with experiments and came to the conclusion that helium is continuously produced by radium. The experiments consisted in examining in a spark tube the spectrum of the radioactive gas, or emanation, given on dissolving in water fifty milligrams of nearly pure radium bromide that had been in the solid state for some time. This radioactive gas is not stable, but decays in a geometrical progression with the time, the rate being about half in four days. Of course the most careful precautions were taken to free the spark tube from foreign gases, especially hydrogen, oxygen and carbon dioxide. When first prepared the tube gave a new and hitherto unknown spectrum, probably that of the radioactive gas. After four days the lines of the helium spectrum began to appear, growing brighter for several days, while the new spectrum observed at ​first disappeared. The supposition is that the helium is the product of the atomic decomposition of the radioactive gas. It may be argued that the experiments only prove that radium is not an element, but only a compound of staple elements. On the other hand, the production of this radioactive gas is not influenced by changes of temperature, which is true of no chemical process, and is accompanied by radioactivity, which is not a phenomenon of chemical changes.
The wide distribution of radioactive matter has been brought to light by the work of Professors Elster and Geitel in Germany on the radioactivity of the atmosphere and soils, and by a number of observers under the leadership of Professor J. J. Thomson on the presence of a radioactive gas in many spring and well waters. Elster and Geitel discovered that clay is much more active than other soils, apparently from the presence of a trace of radium, though much depends on the locality. A certain clay which they
examined contained one eleven-hundredth as much radium as pitchblende, the ore from which radium is extracted. Radium salts are found to give off heat at a very considerable rate. M. Curie estimates that radium can melt its weight of ice in an hour. A more exact investigation by Rutherford and Barnes shows that the radioactive gas and the secondary activity are the chief sources of the heating effect.
not recommended when an operation is practicable. Numerous other cases of the beneficial results of the radium treatment have been reported in this country and England.
More exact measurements by other observers corroborate the conclusion of Rutherford that the radiations from radium which are the least penetrating of the three types present, but represent the greater part of the energy,
consist of positively charged particles of about twice the mass of the hydrogen atom, and moving with a velocity about one tenth that of light.
The supply of radium on the market is very uncertain. All of it is imported from France or Germany, and the price has recently been going higher. Many efforts are being made to extract radium in this country from carnotite, an ore of uranium that is found in considerable abundance in Colorado and ​
Utah. These efforts have met with some degree of success, but radium from carnotite is not yet on the market.
NEW BUILDINGS FOR THE DEPARTMENT OF AGRICULTURE AT WASHINGTON.
The plans for the new buildings for the National Department of Agriculture contemplate a group of ten buildings, arranged in the form of a quadrangle, with an administration building as the central feature. The nine laboratory buildings will be units, and will be connected with the administration building by covered corridors. They will be 60 by 200 feet each in size and 4 stories in height above a high, well-lighted basement. The administration building will be about 135 by 160 feet and 5 stories high. The latter, with a laboratory building on either side, will present an imposing front of 700 feet, which will face south on the broad parkway planned to extend from the Capitol to the Washington Monument.
The appropriation of $1,500,000 made by congress will provide for the i erection of three laboratory buildings, leaving the administration building and the others to be provided for later. As the new site is some distance removed from the site of the present buildings, the latter can remain in use in the meantime. The three new buildings will provide accommodations for the laboratories and offices of the department now occupying rented buildings, as was directed by congress.
The buildings will be classic in design and will probably be built of marble. The construction will be of the most substantial character, with thick walls carrying heating and ventilating flues. The interior space will be divided into units 20 by 20 feet, and each unit will have access to a conduit furnishing water, steam, gas, electricity, air pressure and exhaust. The actual arrangement of the laboratories has not yet been settled, nor has it been definitely decided which three of the laboratory buildings will be erected now.
The department is now occupying very inadequate and in many cases temporary quarters, and is paying an annual rental of about $25,000 for buildings located outside the department grounds. Its main building was long since condemned and is in no sense a modern structure. The staff of the department at the time it was erected included less than 100 persons; the present enrollment is about 4,200 ​persons. A group of buildings in keeping with the dignity and importance of agriculture in our national economy and significant of the service of the Department of Agriculture to the country at large, is greatly to be desired. A year from now congress will probably be asked to provide further funds, so that the administration building (estimated to cost $1,000,000) and possibly other laboratory buildings may be erected.
SCIENTIFIC ITEMS.
We regret to announce the deaths of Dr. Charles Emerson Beecher, professor of historical geology at Yale University and a member of the governing board of the Sheffield Scientific School; of Dr. Emil Alexander de Schweinitz, chief of the Biochemic Division, U. S. Department of Agriculture; of Arthur William Palmer, D.Sc. (Harvard), head of the Department of Chemistry of the University of Illinois, and of Miss Anna Winlock, computer and assistant in the Harvard College Observatory.
Dr. David Duncan, having been entrusted by the late Mr. Herbert Spencer with the writing of his biography, will be obliged to persons who may possess letters from him of value if they will kindly lend them for the purpose of such biograpny. All letters addressed to Dr. D. Duncan, care of H. R. Tedder, Esq., secretary, the Athenaeum, Pall-mall, London, S. W., will be carefully preserved and returned in due course to their owners. Mr. Spencer's autobiography will be published by Messrs. D. Appleton & Co., on March 25.
The steamship Princess Irene, bringing the remains of James Smithson, arrived in New York on January 20. These were transferred to the Dolphin of the U. S. Navy and taken to Washington. They have been deposited in the Smithsonian Institution until arrangements can be made for suitable burial in the grounds of the institution and the erection of a monument. The remains were brought to this country by Dr. A. Graham Bell, at whose instance the regents arranged for the removal, owing to the fact that the English cemetery at Genoa in which Smithson was buried was to be abandoned.
At the annual meeting of the Royal Astronomical Society on February 12, Ambassador Choate received the society's gold medal on behalf of Professor George E. Hale, of the Yerkes Observatory.—The Lalande prize in astronomy has been conferred upon Director W. W. Campbell, of the Lick Observatory, by the Paris Academy of Sciences.—The French minister of public instruction and fine arts has conferred the degree of officer of public instruction upon Dr. Lester F. Ward for his scientific and sociological works.