Obituary notices of fellows deceased

Carl Georg Friedrich Rudolf Leuckart was born in the ancient university town of Helmstedt, on the 7th October, 1822, and died at Leipzig in his 76th year on February 6, 1898. He was elected a Foreign Member of the Royal Society in 1877. Leuckart was the nephew of a celebrated but less distinguished zoologist, Frederick Sigismund Leuckart, who does not appear to have had any share in directing the tastes of his younger relative.

Preface

At their meeting of March 22, 1900, the Council resolved:— “That the Obituaries of deceased Fellows, in addition to appearing in the ‘Year-Book,’ be issued, either yearly or at such other intervals as may seem desirable, in a volume uniform with the ‘Proceedings.’” The present volume, containing the Obituary Notices in the Year-Books for 1900 and 1901 is accordingly issued, and will be followed at suitable intervals by similar collections from future issues of the Year-Book. Two or three notices will be found at the end of the collection which were not included in the Year-Book for 1901. It has been thought convenient to add a general index to all the Obituaries that have appeared in the volumes of the “Proceedings” since their publication was commenced, which was in vol. 10, published in 1860.

The decomposition of ammonia by heat.

This subject has been already dealt with by Ramsay and Young, who heated ammonia in glass tubes at various temperatures, and found that decomposition began under the most favourable circumstances at a little below 500°, and that the amount decomposed depends on the extent of the heated surface of the solid with which the ammonia is in contact, on the nature of the surface, and on the time of exposure to heat. We have thought it desirable to extend our knowledge of the subject still further by investigating the rate of decomposition at various temperatures. The ammonia was contained in porcelain vessels heated in a muffle furnace, and the decomposition was traced by reading the pressure on a mercury manometer, the sum of the volumes of the ammonia and products of decomposition being kept constant.

On certain properties of the alloys of silver and cadmium.

It has long been known that an alloy of silver and copper is not satisfactory material for the trial plates which are used in testing the fineness of the Imperial silver coin and of silver wares before they ar hall-marked. As long ago as the year 1580 the lack of homogeneity of silver-copper alloys was well known to the German metallurgists, and in 1852 Levol concluded that the only uniform alloy of the series contained 718.93 parts of silver and 281.07 parts of copper a composition which corresponds to the formula Ag 3 Cu 2 .

On the physical relation of chloroform to blood.

In connection with the preliminary communication by Moore and Roaf on certain physical and chemical properties of solutions of chloro­form in water, saline, serum, and hæmoglobin,* it may be of interest to publish the following communication.

Further observations on slip-bands in metallic fractures.—Preliminary note.

The main purpose of the present paper is to describe what the author believes to be a novel method of investigating the micro-structure of metals, and to give some account of preliminary results obtained by its aid. The method was devised in order to throw further light on the true nature of slip-bands, and the preliminary results relate mainly to this question. The investigation described in this paper is thus a further development of researches carried out in the first place by Professor J. A. Ewing, F. R. S. and the author jointly (“The Crystalline Structure of Metals,” Bakerian Lecture, 1899), and subsequently by the present author alone (“The Plastic Yielding of Iron and Steel.”) In the course of correspondence on the latter paper, M. F. Osmond drew the attention of the author to certain experimental facts concerning the behaviour of slip-bands under oblique illumination, which had formerly escaped attention.

On the conversion of electric oscillations into continuous currents by means of a vacuum valve.

An electric oscillation being an alternating current of very high frequency, cannot directly affect an ordinary movable coil or movable needle galvanometer. Appliances generally used for detecting electric waves or electric oscillations are, therefore, in fact, alternating current instruments, and must depend for their action upon some property which is independent of the direction of the current, such as the heating effect or magnetizing force. The coherer used in Hertzian wave research is not metrical, since the action is merely catastrophic or accidental, and bears no very definite relation to the energy of the oscillation which starts it. Even the demagnetising action of electric oscillations, though more definite in operation than the contact action at loose joints, is far from being all that is required for quantitative research.

Studies on enzyme action. V.—Hydrolysis of isomeric glucosides and galactosides by acids and enzymes.

In view of the use constantly made, in contrasting the action of sucroclastic enzymes, of the stereoisomeric α- and β-methyl glucosides and the corresponding galactosides as test materials, it was desirable to gain some idea of the relative stability of these four compounds in presence of acids and wherever possible towards enzymes, a know­ledge of their behaviour being of importance, both as throwing light on their intrinsic properties and for the purpose of correlating the activities of the various compounds amenable to hydrolysis.

On the general circulation of the atmosphere in middle and higher latitudes.

In the course of an investigation into the trajectories, or actual paths of air, by means of synoptic charts, which is still in progress,* it became apparent that the paths of air taking part in cyclonic dis­turbances near the British Isles when traced backward did not always originate in anti-cylonic areas, but followed a track skirting the neighbouring high-pressure areas and traversing sometimes a very large part of a belt of the earth in a direction more or less parallel to a line of latitude, and, on the other hand, air moving in the neighbour­hood of a cyclonic depression did not invariably seek the nearest baro­metric minimum, but sometimes passed on, leaving the circulation of the depression on the left hand.