November, 1913. 



KNOWLEDGE. 



429 



Mr. Houston also calls attention to the striking differences 

 between the death-rates from typhoid shown by European 

 and American cities. This is illustrated by examples of which 

 the following may be quoted : — 



In Mr. Houston's opinion the excessive prevalence of 

 endemic typhoid fever in American cities is probably due to 

 the "carrier" element, rather than to the consumption of 

 impure water in the ordinary sense ; since it can be shown by 

 calculation that an ordinary glass of properly purified water 

 will probably not contain a single typhoid bacillus. 



CHEMISTRY AT THE BRITISH ASSOCIATION.— 

 Twenty-seven years had passed since a meeting of the British 

 Association had been held in Birmingham. It was at the 

 former meeting in 1886 that Sir William Crookes suggested 

 that the elements might have been evolved from a hypo- 

 thetical primordial substance or Urthyl. It was therefore 

 appropriate for the President of the Chemical Section, Dr. 

 Wynne, to review the progress that has been made in this and 

 other directions during the last quarter of a century. 



With regard to the brilliant hypothesis of Sir William 

 Crookes, the President pointed out that this common origin of 

 all the elements was now commonly accepted, although " the 

 question whether the term ' transmutation ' is verifiable under 

 available conditions is answered differently according to the 

 view we take of the disintegration of radium and kindred 

 phenomena." 



The main portion of Dr. Wynne's address, however, was 

 occupied with a discussion of the chemical change known as 

 substitution from the point of view of Werner's conception of 

 valency, according to which an atom may possess both a 

 principal and an auxiliary or residual valency. 



The reports of two committees were presented to the 

 section, one dealing with " Dynamic Isomerism " and the 

 other with " The Study of Plant Enzymes." In the latter an 

 outline is given of the evidence in support of the view that the 

 pigments in the sap of plants are produced by the oxidation of 

 a colourless chromogen by means of an oxidising enzyme or 

 oxydase. 



Most of the papers read before the section were of a highly 

 technical character, and implied a good knowledge of 

 physical and organic chemistry on the part of the audience. 



Of more general interest, however, were the communications 

 upon radio-active elements. The investigations of Mr. Fleck 

 during the last year have shown that of the eleven new radio- 

 active elements studied all, with the exception of Uranium X, 

 are chemically identical with common elements already 

 known, such as lead, thallium, and thorium. 



In Mr. Soddy's paper upon " The Radio-Elements and the 

 Periodic Law " the conclusion is drawn that " in that part of 

 the Periodic Table in which the evolution of the elements is 

 still proceeding each place is seen to be occupied, not by one 

 element, but on the average, for the places occupied at all, 

 by no less than four, the atomic weights of which vary over as 

 much as eight units. It is impossible to believe that the same 

 may not be true of the rest of the table, and that each known 

 element may be a group of non-separable elements occupying 



the same place, the atomic weight not being a real constant, 

 but a mean value, of much less fundamental interest than has 

 hitherto been supposed." 



The communications dealing with applied chemistry 

 included one upon " The Effect of Impurities on the Quality of 

 Commercial Copper," by Mr. F. Johnson, and " The Action of 

 an Alkaline Natural Water on Lead," by Messrs. Liverseege 

 and Knapp, an outline of which will be given later. 



ENGINEERING AND METALLURGICAL. 



By T. Stenhouse, B.Sc, A.R.S.M., F.I.C. 



CORROSION OF CONDENSER TUBES.— The results 

 of a long series of experiments carried out with the object of 

 examining some of the factors which seemed likely to bear 

 upon the nature and speed of corrosion in condenser tubes 

 were communicated to the August meeting of the Institute of 

 Metals by Dr. G. D. Bengough and Mr. R. M. Jones. Tubes 

 of four standard compositions were immersed in stationary 

 sea-water at different temperatures, and similar tubes were 

 used in an experimental condenser plant. The results show 

 that the temperature is a very important factor in determining 

 both the nature of the chemical reactions between sea-water 

 and brass, and also the speed with which the brass is attacked. 

 Action is much more rapid at higher temperatures and the 

 experiments demonstrate the bad economy of overloading 

 condensers. The authors made direct experiments to test the 

 theory that particles of coke, and so on, deposited in the 

 tubes give rise to local galvanic action, resulting in pittings, 

 but could find no evidence of this action taking place. From 

 their experiments they conclude that selective corrosion, 

 resulting in dezincification and pitting, is an inherent property 

 of the alloys examined. They consider that the Admiralty 

 alloy, copper 70, zinc 29, tin 1, and Muntz's special brass, 

 copper 70, zinc 28, lead 2, are more suitable for condenser 

 tubes than plain brass composed of copper 70, zinc 30, 

 and they recommend the extended use of electro-chemical 

 protection. 



THE CRITICAL POINTS OF STEEL.— A method of 

 determining the critical points Ar 1 and Ac 1 without the use 

 of a pyrometer is described by Dr. J. E. Stead in a paper read 

 before the Iron and Steel Institute at the September meeting. 

 Two bars of the steel are supported, without touching each 

 other, in a short length of porcelain tube, which is then 

 inserted in the side of a muffle furnace. The bars are 

 allowed to remain until the temperature conditions become 

 constant, the inner ends of the bars being at a temperature of 

 about 1000° C, and the outer ends below 700° C. One bar is 

 then withdrawn for about 15 mm., and the heating continued 

 for about fifteen minutes more. Thin wires of pure silver, 

 aluminium, zinc, and so on, are then inserted in the space 

 between the bars, and the points on the bars where the wires 

 just melt are ascertained. A scale can thus be plotted showing 

 the temperature at each point along the bars. The bars are 

 then withdrawn, quenched, cleaned, and etched, whereby the 

 line of demarcation between the hard and soft portions 

 becomes clearly visible. A reference to the scale gives the 

 temperatures which the bars had at these planes when in the 

 furnace. The withdrawn bar gives the Ar 1 point, and the 

 other bar the Ac 1 point. The results obtained in this way 

 are stated to be within 3° C. of the truth. 



GEOGRAPHY. 



By A. Stevens, M.A., B.Sc. 



THE DISTRIBUTION OF MAN.— The Presidential 

 Address of Professor H. N. Dickson to Section E (Geography) 

 of the British Association dealt with the question of the 

 Redistribution of Mankind, and recently there has been pub- 

 lished a good deal of matter bearing on the subject. The 

 discussion of the problem is bound up with the discussion of 

 resources, but there are certain questions of resources that 

 are of necessity more or less indefinite and incapable of even 

 probable solution. Such deal with coal supply, in general and 



