August 17, 191 1] 



NATURE 



35 



There is at the present time a good deal of sporadic 

 information as to the water supplies and resources in 

 various localities, and mining engineers have, from their 

 experience, some knowledge of the subsoil or underground 

 Katers, lor these, of course, are the enemy with which 

 they have to contend in their operations ; but there is no 

 general survey to determine what are the supplies and 

 What are the water resources of this country ; there is no 

 general knowledge as to the underground water supplies. 

 We know that in many districts these are being pumped 

 for supply ; in many where mining is going on they are, 

 with reckless economy, being pumped to waste. But what 

 is required is a comprehensive knowledge both of the 

 overground and underground reserve forces for water 

 supply, and until that is prepared any legislation with re- 

 gard to water supply must be merely hand to mouth, un- 

 scientific, and futile ; and this seems to have been the wise 

 opinion of Mr. Lithiby, of the Board of Trade, who gave 

 evidence before the Joint Select Committee on the Water 

 Supplies Protection Bill, which sat and reported during the 

 last session of Parliament. 



The necessity for the acquisition of such knowledge is 

 emphasised by the proceedings and report of the Royal 

 Commission which has been inquiring and reporting upon 

 canals and waterways since the year 1906. No one can 

 say that the investigations of that commission have not 

 been exhaustive, although many may think that the 

 reservations of Lord Farrer and three other commissioners 

 seem to show that their labours will prove absolutely futile. 

 But the commission has gone further, and proposes to 

 improve the waterways of England, and great new or 

 improved canals are to connect the Midlands and South 

 Staffordshire with the estuaries of the Thames, the 

 Humber, the Mersey, and the Severn. These four routes, 

 which are, after all, only to be large barge canals, suited 

 for barges of, in one scheme, 100 tons burden, and in 

 another of 300 tons burden, are, in the report, referred to 

 as the " cross," and if this gigantic scheme is carried out 

 at an expense, according to Sir John Wolfe Barry's 

 estimate, of, for the small scheme, 13,393,483!., or for the 

 large scheme of 24,513,823!., certainly England would be 

 financially crucified. But criticism of that imaginative 

 proposal forms no part of my present purpose. It is only 

 interesting to me to note that after the commission had 

 adumbrated this idea, and ascertained approximately the 

 cost of constructing the " cross," which, as I have said, 

 would be a cross greater than England could bear, they 

 bethought themselves how they were to get water for their 

 canals — 5n the deplorable absence of the Alps — and they 

 instructed an engineer to survey and inquire and to give 

 them an estimate of the cost of getting the water. I have 

 no doubt he did his work as well as he could. He found 

 ready to his hand the admirable statistics as to rainfall 

 which are collected by Dr. Mills, but complains, rightly 

 enough, that " other questions connected with the national 

 water supplies appear to receive less attention." Of 

 course, it is quite an exception to find anywhere river 

 gaugings, and the engineer in question says : — " This 

 inquiry has shown the necessity, if such problems 

 which the following reports attempt to 

 to be thoroughly investigated in future, of 

 some public authority being charged with the duty of 

 recording the flow of rivers, and of the proportion of 

 ill available or run-off in catchment basins over- 

 lying different geological strata in various parts of the 

 country. " 



But this claim to water for canals, which, according to 

 the reporter, would involve an expenditure of 1,194,000!-, 

 without including the cost of obtaining the power or the 

 cost of water compensation, and is, of course, in 

 addition to the sums estimated for construction by Sir 

 John Wolfe Barry, raises again in an acute form the 

 whole question of our national supplies, and points to the 

 absolute necessity now of some systematic dealing with 

 this great question. The nation is being forestalled by 

 municipalities, and here is a suggestion that a Canal 

 Board should lay a gigantic hand upon some of our sources 

 of supply. The time for dealing with the matter is now ■ 

 but, as in other cases, it is quite likely that the matter 

 will he postponed until it is " too late." 



SELF-LUMINOUS NIGHT HAZE.' 

 'THERE is one phase of the night skies which does not 

 seem to have received much or any attention. It is 

 the occasional presence of self-luminous haze. This matter 

 does not seem to be similar to the luminous night clouds, 

 "die leuchtenden Nachtwolken," which were observed by 

 O. Jesse and others some twenty-five or thirty years ago, 

 and were found to be clouds at such great altitudes above 

 the earth's surface (upwards of 50 miles high) that they 

 received the sunlight long after or before the ordinary 

 clouds. The observations of O. Jesse were printed in the 

 Astronomiscke Nachrichten, Bd. 121, pp. 73, m; Bd. 130, 

 p. 425; Bd. 133, p. 131; Bd. 140, p. 161. In Astro- 

 nomiscke Nachrichten, Bd. 140 (No. 3347), he gives a long 

 list of altitudes, determined by photography, which range 

 from 81 km. to S7 km. The mean value given by the 

 observations from 1885 to 1891 was 82 km. (52 miles). 

 These clouds were seen in the northern hemisphere only 

 near the time of the summer solstice. In the southern 

 hemisphere they were seen at the opposite season. From 

 his papers it is clear that these sunlit clouds were in no 

 way related to the present subject, and I only mention 

 them to forestall any suggestion that they were similar to 

 the ones seen by me. 



The objects to be described here were apparently at the 

 altitude of the ordinary higher clouds. They have been 

 seen in all parts of the sky and at all hours of the night. 

 In a paper on the aurora 3 I have previously directed atten- 

 tion to the frequent luminous condition of the sky at night. 

 This feature long ago impressed itself upon me. Indeed, 

 anyone who has spent much time under the open sky 

 hunting comets, &c, will have been forcibly impressed with 

 this peculiarity. In most cases this illumination has been 

 due, evidently, to a diffusion of the general star light, 

 perhaps by moisture in the air. This latter condition is 

 present as a whitening of the sky, which gives it a 

 " milky " appearance. At other times the sky is more or 

 less feebly luminous; but the luminosity is different from 

 the other condition, and is evidently not due to a diffusion 

 of star light. In reality, the sky seems to be self-luminous. 

 Sometimes the whole sky has this appearance, and at other 

 times a large portion only. At times the illumination is so 

 great that the face of an ordinary watch can be read with 

 no other light than that of the sky. It is indeed seldom 

 that the sky is rich and dark. In any determination of 

 the total amount of the light of the sky the results must 

 be uncertain, because of the great changes that so often 

 take place in the amount of the illumination. The self- 

 luminous condition frequently occurs when no ordinary 

 indications of an aurora are present. It is, nevertheless, 

 doubtless of an auroral nature, for Prof. Campbell has 

 shown that the spectrum of the aurora is essentially always 

 present on a clear dark night (Astrophysical Journal, 2, 

 August, 1895, p. 162). . 



I have given an account 5 of the remarkable pulsating 

 clouds of light that are seen here occasionally, which 

 usually, but not always, have an easterly motion — gener- 

 ally south-east. They are mostly confined to the northern 

 half of the heavens. There is another phenomenon that 

 has been visible on a number of nights of last year, and 

 also in the present year, of which I have seen no record. 

 This consists, usually, of long strips of diffused luminous 

 haze. I believe that this is really ordinary haze which for 

 some reason becomes self-luminous. It is not confined to 

 any particular region of the sky nor to any hour of the 

 night. It alwavs has a slow drifting motion among the 

 stars. This motion is comparable with that of the ordinary 

 hazy, streaky clouds that are often seen in the daytime. 

 They are usually straight and diffused, and as much as 

 50° "or more in length and 3 or 4 or more in width. In 

 some cases thev are as bright, or nearly as bright, as the 

 average portions of the Milky Way— that is, _ they are 

 decidedly noticeable when one's attention is directed to 

 them. Thev apparentlv are about as transparent as 

 ordinary haze. Sometimes, when seen near the horizon, 



1 From a paper read before the American Philosophical Society on April 

 -,, by Prof E. E. Barnard. 



thysical Journal, 31, April, ioto. 



:! Astrofhyshal Journal, 31, April, 1910, p. 210, &c. 



NO. 2l8l, VOL. 87] 



