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AND 



BOSTON JOURNAL OF CHEMISTRY. 



Volume XXII. 



BOSTON, OCTOBER, 1888. 



Number 10. 



CONTENTS. 



Familiab Scikncb. — J. H. Debray 146 



Notes for Amateur Photographers . .' 14o 



The Royal Botanical Gardens at Kew 146 



The Tendency of Matter at the Surface of the Earth 147 



Paris Letter 147 



Scientific Brevities ]4« 



Practical Chemi8tby and thb Abts. — Nickel and Cobalt : 



the Twin Metals 149 



Kerkook Petroleum Sprint's, Asia Minor 149 



Windmills for Electric Lightinj; 149 



Association of Hydrocarbons with Rock-Salt in Nature.... 149 



A Useful Table 150 



The Aniline Industry in Germany 150 



liail road Notes 150 



Industrial Memoranda 150 



Home, Farm, AND Garden. — Orchids 151 



The Oak-Pruncr 151 



Toilet Recipes of Ancient Egypt 152 



The Rapid Defoliation of Trees 152 



Gleanings 152 



Editorial. — The Cleveland Meeting of the American 



Association 153 



Meteorology for AugU8t,1888, with Review of the Summer, 154 



Astronomical Phenomena for October, 1888 155 



Questions and Answers Iij5 



Literary Notes 155 



Medicine and Pharmacy. — The Amenities of the Doctor's 



Life 166 



cutis 156 



Monthly Summary of Medical Progress 157 



The Diagnosis of Human Blood 157 



Medical Memoranda 158 



Humors 158 



Publishers' Column 158 



fsmtltac S)C(rnte. 



J. H. DEBRAY. 



We give below a portiait of the distin- 

 guished French chemist .1. H. Uebray, who 

 died at Paris on the tenlh day of last Jul^', at 

 the age of sixty-one years. 



The name of Debra3- is almost constantly 

 associated with that of Deville, who was at 

 first his instructor in chemistiy, but who soon 

 became his co-worker, — a connection which 

 was kept up for many years, until the retire- 

 ment of Deville from active work. 



Debray made numerous investigations upon 

 glucinium, molybdenum, tungsten, and allied 

 elements, in the line of synthetic mineralogy- ; 

 but it maj' be said that his two principal 

 works were his studies of the platinum group 

 of metals and his researches upon the disso- 

 ciation of chemical compounds. In connec- 

 tion with his friend Deville, he made a most 

 exhaustive study of the pi-operties of plati- 

 num and the metals chemically allied to it. 

 The investigations extended over a term of 

 twenty jears, and added much to our knowl- 

 edge of these peculiar elements, besides hav- 

 ing great practical value in determining the 

 best met&llurgical methods for smelting and 

 working these useful and valuable metals. 



In taking up the study of the laws of disso- 

 ciation, he entered a field alieady opened by 

 Deville. He showed, that, when many chem- 

 ical compounds are submitted to the action 

 of heat in closed vessels, they are decom- 



posed into their constituents, and that this 

 decomposition is dependent upon temperature 

 and pressure, and is governed by exact laws. 

 He found, for example, that when carbon- 

 ate of lime is heated in a closed vessel, at a 

 low red heat it is decomposed, and carbonic 

 dioxide is given off, but that at a temperature 

 of about 1580° F. the decomposition ceases 

 as soon as the disengaged carbonic deposit 

 acquires a tension of 85 millimeters (3^ inches) . 

 If the temperature is increased to 1904° F. 

 the decomposition is not arrested until the ten- 

 sion of the confined gas equals 520 millimeters 

 (20 inches). These phenomena are analogous 

 to those of the solution of solids and the 

 vaporization of liquids, and not onl_y are of 

 the highest importance from a chemical point 



of view, but indicate the connection between 

 chemical and phj-sical laws. 



Debraj' was a member of the faculty of the 

 Normal School at Paris, and in charge of its 

 laboratory. Under his care and that of his 

 predecessor, Deville, man^' celebrated chemists 

 have received their education in this labora- 

 tory, and much valuable work has been accom- 

 plished, among which maj- be mentioned the 

 isolation of the element fluorine by Moissan. 

 He was in ever}- waj- a most eminent and dis- 

 tinguished chemist, and his loss will be severely 

 felt in scientific circles. 



NOTES FOR AMATEUR PHOTOGRAPHERS. 

 The advantage of keeping the developing 

 fluid on a plate in constant motion is indisput- 

 able. The development proceeds more evenly, 

 air-bubbles are removed, and spots and streaks 

 are to a large extent prevented. We illustrate 

 a simple mechanical arrangement (Fig. 1) on 



the principle of the pendulum, which can be 

 made by any amateur, and will be found very 

 convenient. The supporting framework is 

 made of stout wire covered with rubber tubin<r. 



Glass rods might be substituted if one has a 

 little skill in glass-blowing. It is onl}' neces- 

 sary to fill the tray with the developing fluid, 

 immerse the plate, and set the apparatus in 



motion, which will continue for a period long 

 enough for the development of the most re- 

 fractory plate. 



The " photographic spectre " (Fig. 2) is an 

 amusing application of the process, sadly 



