Nov. 29, 1888 



NATURE 



117 



I 



organic or inorganic, should be within the scope of the joint 

 Society, their inclusion in a Mineralogical Magazine would 

 suggest a misnomer. The change or extension of our already 

 lengthy title has its evident inconveniences, but it may be worthy 

 of careful deliberation by the Society at so ne early date as to 

 whether such an extension is not really necessary for the clearer 

 definition of our objects if we are td enlist the sympathy of 

 many who, though they may feel to be beyond the pale of a 

 Mineralogical Society, yet by their investigation of the crystalline 

 forms of the products of the laboratory may in the future, as 

 in the past, throw light on the crystallography of the Mineral 

 Kingdom. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Cambridge. — The following gentlemen have been appointed 

 examiners : — 



Mathematical Tripos, Part II. : Dr. Routh (Chairman), 

 Messrs. W. Burnside, J. Larmor, and A. R. Forsyth. 



Natural Sciences Tripos and 2nd M. B. : Dr. Hill (Master of 

 Downing), Prof. Cleland (Human Anatomy), Prof. Stirling, 

 Dr. Gaskell (Physiology). 



Natural Sciences Tripos : Prof. W. G. Adams, Mr. W. N. 

 Shaw (Physics), Prof W. A. Tilden, Mr. H. J. H. Fenton 

 (Chemistry), Prof. Lewis, Prof. Story-Maskelyne (Mineralogy), 

 Mr. F. Darwin, Prof H. Marshall Ward (Botany), Mr. W. F. 

 R. Weldon, Mr. F. S. Harmer (Zoology). 



Natural Science Tripos and Special B.A. : Mr. W. W. Watts, 

 Mr. A. Harker (Geology). 



M.B. and Special B.A. : Prof. W. G. Adams, Mr. S. L. Hart 

 (Klementary Physics), Mr. H. F. Neville and Mr. H. J. H. 

 Fenton (Elementary Chemistry), Mr. F. Darwin and Mr. S. F. 

 Harmer (Elementary Biology). 



2nd M.B. only: Mr. Pattison Muir and Mr. H. Robinson 

 < Pharmaceutical Chemistry). 



Messrs. W. Carruthers, F.R.S., and J. E. Marr are ap- 

 pointed examiners for the Sedgwick Prize to be adjudged in 

 1892. 



The University Lectureships in Botany and Advanced Human 

 Anatomy, tenable for five years, are vacant. Candidates must 

 -end their names to the Vice-Chancellor on or before 

 November 30. 



Open Scholarships and Exhibitions will be competed for at the 

 following Colleges, beginning on the undermentioned dates : 

 Mathematics, Pembroke, December ii ; Trinity Hall, Decem- 

 ber 11; Queens', December \i \ Mathematics and Natural 

 Science, Gonville and Caius, December 7 ; King's, December 

 10; Jesus, Christ's, and Emmanuel combined, December li ; 

 St. John's, December 11 ; Trinity, December 11 ; Sidney 

 Sussex, January I. The tutors will give full information. 



The Sheepshanks' Astronomical Exhibition will be competed 

 for on December 10 and 11 at Trinity College. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, November 15. — " Combustion in Dried 

 Oxygen." By H. Brereton Baker, Dulwich College, late Scholar 

 of Balliol College, Oxford. Communicated by Prof, H, B,. 

 Dixon, F.R.S. 



In 1884, some preliminary experiments, published in the 

 Journal of the Chemical Society, convinced me that moisture 

 exerted an important influence on the combustion of carbon. 

 Since that time experiments have been made, not only with that 

 clement but with several others, and the same influence seems to 

 be exerted on the combustion of some, while no such influence 

 could be detected in the case of other elements. It was dis- 

 covered very early in the investigation that hydrogen, both free 

 and combined, aided the union of carbon with dried oxygen, 

 and therefore, for the new experiments on this and other elements, 

 s^^ecial attention was devoted to their purification from hydrogen. 

 It was found that two of these elements, amorphous phosphorus 

 and boroB, had, like carbon, a very great power of occluding 

 hydrogen. To eliminate it some of the elements were heated in 

 a current of pure chlorine, while others were heated in sealed 

 tubes with the chlorides of the elements, special precautions 



being taken to free the purified elements from all traces of the 

 agents used in their purification. In this way the elements — 

 carbon, sulphur, boron, and phosphorus, the latter in both red 

 and yellow modifications — were found to have their combustion 

 influenced by the dryness of the oxygen. Some chemical union 

 was found to take place, the extent of which varied with the 

 dryness of the substances. In no case, however, did it manifest 

 itself by flame. Ordinary phosphorus was obtained so pure as 

 not to glow in the oxygen dried by phosphorus pentoxide, though 

 the pressure was increased and diminished in every possible way. 

 If water was added, rapid combustion at once set in. 



The elements — selenium, tellurium, arsenic, and antimony — 

 were purified with as much care as was expended on the elements 

 mentioned above. Their combustion was, however, not found 

 to be affected in any way by the dryness of the gas. 



In the course of the investigation two facts were discovered 

 about the combustion (l) of amorphous phosphorus, and (2) of 

 carbon in oxygen. Amorphous phosphorus is generally regarded 

 as being incapable of true combustion. It is asserted that 

 before amorphous phosphorus can be heated to its kindling point, 

 it changes into ordinary phosphorus, which then burns. This 

 has been proved not to be the case. Amorphous phosphorus was 

 heated in a current of nitrogen, free from traces of oxygen, to 

 260°, 278°, and 300° in three experiments, without undergoing 

 any change to the ordinary modification. If moist oxygen was 

 substituted for the nitrogen, combustion took place at 260°. It 

 seems, therefore, probable that amorphous phosphorus undergoes 

 a true combustion in oxygen without previous change to the 

 ordinary modification. 



With regard to the combustion of carbon, it has always been 

 a doubtful question which of the two oxides is first formed. Is 

 carbon monoxide the first product, undergoing further oxidation 

 to the dioxide, or is carbon dioxide the first and only substance 

 formed ? The problem seems incapable of direct solution. It 

 is, however, open to indirect attack. When carbon is heated in 

 a current of partially dried oxygen, a slow combustion goes on, 

 and, though the oxygen is in excess, both oxides are produced. 

 The amount of monoxide, however, is twenty times the amount 

 of the dioxide. Experiments also show that this occurs at 

 temperatures at which dry carbon dioxide is not reduced by 

 carbon. The carbon monoxide must, therefore, be produced by 

 the direct union of hs elements, its further oxidation being pre- 

 vented by the dryness of the gases. Confirmatory experiments 

 were performed in which carbon monoxide was found to be pro- 

 duced by the slow combustion of carbon in air at 440", a 

 temperature too low for the reduction of the dioxide by carbon. 

 It is probable that the ordinary combustion of carbon goes on in 

 two stages, that carbon monoxide is first produced, and, if cir- 

 cumstances are favourable, this is further oxidized to carbon 

 dioxide. 



**0n the Secretion of Saliva, chiefly on the Secretion of Salts 

 in it." By J. N. Langley, M.A., F.R.S., Fellow of Trinity 

 College, and H. M. Fletcher, B.A., Trinity College, Cambridge. 



Heidenhain has shown that when saliva is obtained by stimu- 

 lating the chorda tympani, the percentage of salts in the saliva 

 depends upon the rate of secretion, so that the faster the secretion 

 the higher the percentage of salts is up to a limit of about o"6 

 per cent. 



The authors do not find any rate of secretion beyond which 

 an increase in rate fails to increase the percentage of salts in the 

 saliva. The increment in the percentage of salts decrease*, 

 however, with each equal successive increment in the rate of 

 secretion. 



As a rule, in saliva obtained by injecting pilocarpine, the per- 

 centage of salts follows Heidenhain's law ; the exceptions are 

 probably due to the action of pilocarpine upon the circulation. 



The percentage of salts in saliva obtained by stimulating the 

 sympathetic is higher than corresponds to its rate of secretion, 

 the saliva obtained by stimulating the chorda being taken as a 

 basis of comparison ; this sympathetic saliva may be secreted at 

 lijth of the rate of chorda saliva, and yet contain very nearly as 

 high a percentage of salts. 



Dyspnoea decreases the rate of secretion of saliva with a given 

 stimulus, and if not too prolonged, increases the percentage of 

 salts, and tends to increase the percentage of organic substance 

 in the saliva. 



Clamping the carotid during secretion has the same general 

 effect as dyspna-a, but it causes a still more marked increase in 

 the percentage of salts. Its after-effect is also much greater, and 

 lasts longer. 



