July 8, 1909] 



NA TURE 



47 



The Solar Constant and the Apparent Temperature 

 OF THE Sun. — In a note published in No. 7, vol. Ixix., of 

 the Monthly Notices (p. 611), Dr. F6ry discusses the 

 measurement of the solar constant and of the sun's mean 

 temperature. One of the greatest difficulties in these re- 

 searches is to evaluate the atmospheric absorption, which 

 in published researches has varied from 1-5 to 4 ; it is 

 generally accepted now as having the value 2-4. 



Having designed an instrument for measuring terrestrial 

 high temperatures, MM. F^ry and MiUochau applied it to 

 the determination of the solar temperature by Stefan's 

 law. More than 750 observations were made at different 

 altitudes, and at the summit of Mont Blanc the zenith 

 transmission was found to be o-gi ; with this correction the 

 temperature at the centre of the sun's disc was found to 

 be 5550° absolute, and the mean temperature 5360° C. 

 Before dispatching it to India, this instrument was re- 

 standardised at the National Physical Laboratory, and, on 

 a clear, dry day, gave eight concordant readings, from 

 which the temperature at the centre of the disc was found 

 to be 5153° absolute; on this day the zenith transmission 

 at Teddington was, therefore, 074, or the absorption was 

 26 per cent. 



Employing the accepted value of the constant (2-4), the 

 recent researches give 5920° as the mean temperature of 

 the sun ; but Dr. F^ry thintcs this is too high, and, there- 

 from, deduces that the accepted value of the solar constant 

 is too high. The Mont Blanc measures would indicate 

 165 as the value. 



THE NATIONAL CONSUMPTION OF WATER. 

 A N important paper on the increase in the national 

 ■^ consumption of water was read by Mr. W. R. B. 

 Wiseman before the Royal Statistical Society on April 27. 

 The paper is of considerable interest, and must have 

 entailed a large amount of time and thought on the part 

 of the author. The historical part, which deals with the 

 early history of water supply in England, treats the ques- 

 tion, not only from the general point of view, but gives 

 many interesting details of the early methods adopted and 

 the difficulties met with in many individual towns ; in fact, 

 it is not too much to say that the early beginnings of 

 tlie water supply of all the principal towns in England are 

 reviewed shortly in the paper. It is obvious that, as the 

 object of the paper is to deal with the more modern 

 questions which arise in connection with this subject, the 

 author could not devote very much space to historical 

 details. We can, however, judge that on this subject he 

 has only touched the fringe of the information he has 

 acquired, and it may perhaps not be too much to hope 

 that he may return to this part of his subject at a future 

 date. 



The life of Sir Hugh Myddelton and the description of 

 the work carried out by him of bringing the water from 

 the springs of Chadwell and Amwell, in Hertfordshire, by 

 means of the New River, for the supply of London are 

 well known to most of us, and possibly the author of 

 this paper may have material for the making of a story 

 as interesting and romantic in connection with other 

 towns. 



The author says he was " tempted " to investigate the 

 estimates of the population in the pre-censal period in 

 order to determine whether the great increases in the 

 population in the nineteenth century were abnormal or 

 otherwise, as upon the answer to the query one must 

 be guided in the provision of water supplies for future 

 populations. As was to be expected, he found such an 

 inquiry not of great value. He has, however, put together 

 some interesting information as regards the growth of 

 many towns^ and has dealt with the reasons for the very 

 rapid growth of several of them. From a general review, 

 the conclusion arrived at is that " the nineteenth century 

 was in no wise abnormal, and that a steady increase in 

 the already considerable population may be expected 

 throughout the twentieth century." 



The author describes at some length the methods adopted 

 for checking the waste of water in early days, and par- 

 ticularly the system adopted in Liverpool in 1868 of 

 localising the waste by metering the supply in various 

 districts. 



NO. 2071, VOL. 81] 



Of course, the supply of water per head of population 

 is the important question when dealing with the amount 

 of water required, and the tables given of the supplies in 

 a large number of towns show the variations which exist, 

 and which extend from about sixty gallons as a maximum 

 to below ten gallons as a minimum, leaving out one special 

 case with small population which runs up to 124 gallons 

 per head. The numbers all relate to total supply, which 

 includes domestic, trade, and municipal demands. The 

 statistics given show much greater uniformity of supply in 

 the different towns than would have been anticipated, and 

 it is evident from them that waste of water is carefully 

 looked after in England, and all possible precautions taken 

 to avoid it. If the consumption is compared with what 

 is common in many of the large towns in the United 

 States, where the water supply goes up to 200 gallons 

 and more per head, it will be evident that the precautions 

 taken in England have given very satisfactory results. 

 The opposition to the use of water meters in the United 

 States is probably the reason why leakage and waste con- 

 tinue on a large scale. This opposition is principally due 

 to the view that, on sanitary grounds, it is not well to 

 restrict the supply of water, but, as Mr. F. P. Stearns- 

 stated in his presidential address to the American Society 

 of Civil Engineers, " no one has yet demonstrated the 

 sanitary advantages of a leaky faucet or a defective ball- 

 cock." 



Table No. 5 is a valuable one. It gives, first, the 

 population of more than 120 cities, towns, or districts in- 

 England for two or three years, with intervals, sometimes 

 large and sometimes small, between the years. It then 

 gives the total supply in each of these water areas during 

 the years mentioned, dividing it up under the heads of 

 domestic, trade, and municipal, the daily supply per head 

 of population then following under the san^e heads. 



Considerable space is devoted to the reasons which have 

 caused an increase in the supply of water per head for 

 domestic, trade, and municipal purposes. As regards 

 domestic, it is, of course, well known that the displace- 

 ment of old methods of sewage disposal by the introduc- 

 tion of the water-carriage system was the first cause of 

 the great increase of the water supply. The increased 

 and increasing use of fixed baths must also largely 

 augment the consumption, as the water used for a bath 

 by one person may vary from thirty to one hundred gallons. 

 The author gives various other reasons for the increase 

 in the domestic supply. As regards municipal supply, 

 attention is directed to the increase in consumption due to 

 the public baths, wash-houses, street conveniences, &c. 

 The author states that he has endeavoured for some time 

 past to collect data which will give some idea of the 

 relative proportion of the water supply needed for 

 particular works or industries, but the results have been 

 too meagre to justify definite conclusions. He, however, 

 deals in a general way with the amount of water used in 

 a large number of industries, among which are breweries, 

 distilleries, paper works, textile industries, and many 

 others, and the information given is of an interesting 

 character. The conclusion is that, on the whole, the rate 

 of increase of water supply is greater in recent times than 

 in those more remote. There probably would have been 

 no doubt about this conclusion in anyone's mind, but, 

 although this may be the case, it does not detract from 

 the value of the information which has been collected in 

 this paper to prove it. 



The moral drawn is that, with the increasing amount 

 of water required, there will be an increasing competi- 

 tion for the remaining first-class upland reservoir sites, 

 which will become fewer and fewer as time goes on, and 

 it is therefore desirable that steps should be taken at an 

 early date to create some central authority " which should 

 be charged with the duty of water conservancy in its 

 widest application, and for that purpose should engage in 

 a close and exact study of the water resources of the 

 country." The author then goes more fully into the 

 details which ought to be dealt with by such a body. 



This proposal is, of course, not new, although of great 

 importance. It was dealt with by Mr. E. P. Hill_ in a 

 paper which he read at the Institution of Civil Engineers 

 on November 27, 1906. In the beginning of that paper 

 he said, " the water supply of the country is really a 



