April, 1906.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



413 



an ocean of molten rock — as mig;ht have re-sulted from 

 collision between one large and, possibly, sundry smaller 

 masses; in either case it is easy to see what its future 

 history would be. 



Radiation taking place from the surface only would 

 tend to rapidly lower its temperature there. Convection 

 currents set up in the fluid hereby would constantly 

 maintain an approximately equal temperature through- 

 out the fluid ma,ss; for in a fluid which is of low con- 

 ductivity the effect of conduction is utterly insignificant 

 compared with that of convection. Thus it follows 

 that the temperature would be lowered about uniformly 

 throughout the fluid, so long as fluid existed, and when 

 solidification began the whole would be at about the 

 same temperature, and this temperature would be ap- 

 proximately maintained until the whole was (with the 

 exception of pockets of more fusible matter) completely 

 solidified, for in this case, of course, solidification would 

 take place from the centre outwards. 



Independently, however, of any assumptions we have 

 here made and of any particular hypothesis, the fact to 

 which we would draw attention is indisputable — there 

 is no reason whatever for assuming that because the 

 temperature increases with the depth it does not rapidly 

 tend to a finite limit. This fact was clearly demon- 

 strated by J'homson and Tait in their Natural 

 Philosophy published a quarter of a century ago. 



REVIEWS OF BOOKS. 



Mr. Edwin- Litchfield sends a short article on this 

 sulijecl. After some introductory remarks which have 

 already been imbodied in our previous articles, he con- 

 tinues : " The deeper a mine is, the higher the tem- 

 perature. Let one be sunk half a mile deep, and then, 

 by gigantic labour, make the mine into a valley of ten 

 miles radius — the heat would be gone. Standing on the 

 Welsh or Irish coast, the ground is not hot; dive down 

 into the Atlantic; the " Challenger " did not find the 

 waters beneath to be hot (rather cool), and vet they 

 were five miles nearer the centre of the earth. The 

 cause of heat in mines is from pressure of the 40 

 odd miles of air above, we sink out of our element, and, 

 I suppose, let the air down out of its; and possibb- the 

 gases in the earth exude, and, prrssod down bv the air 

 above, produce heat. 



This is fact. Cold air from the mountains in Switzer- 

 land, passing above the valleys, and the sun's rays 

 penetrating the cold particles, cause the undue heat in 

 the valleys. In Melbourne, the cold wind from the 

 .South Antarctic blowing above the warm air from the 

 North and not letting it rise, causes the burning-hot 

 wind which lasts till the cold becomes the master. 

 Often in this island wc find cold weather follows un- 

 usiuil warm days, from the same cause. 



Were a mine to be sunk through carboniferous rock, 

 and another of even depth, through chalk, the former 

 would be much hf)tter than the latter. It is also out 

 of all conception that the crust of the earth in cooling 

 could bottle up and enclose 7,000 miles diameter of 

 inten.se heat. Should that amount of molten heat, or 

 intensely hot gases be in the interior let us hope it 

 never gets a vent — it woulrl overwhelm the earth and 

 .sea. 



We must raise some other idea to account for 

 volcanoes and hot springs. I am not aware that the 

 Laurcntian, the first formed rock of our globe, so far 

 as wc yet know, shows sign of having been burnt, and 

 deep borings have been sunk into Siluri.m rocks and 

 yet the water comes up cold. 



We might try and find some other reason why di-cp 

 mines are waimcr than the top of the .Alps. 



Elements of Geology, by \V. H. Norton Ginn and Co., 

 the .\th<na;um IVe^s, Boston, U..S.A., pp. 449 and index; 

 6s. 6d.). — Theie is scarcely a page in this book which has not 

 its appropriatv; illustration or diagram, and to British geo- 

 logists the many instances of geological phenomena drawn 

 from the American Continent will prove of great interest 

 and utility. Truly science is a strengthener of the amity of 

 nations, and geology bids fair to bind still firmly together 

 the inhabitants of the old and new worlds. We like the 

 arrangement of this book. The stiffness of arrangement 

 into various departments — dynamical, structural, physio- 

 graphic, historical — has been abandoned, and as each geo- 

 logical process is reviewed, the land-forms and rock-struc- 

 tures which it has produced are treated in turn. The illus- 

 trations are, for the most part, small, but they have not 

 suifered in the process of reduction. The various 

 phenomena portrayed are clear and distinct, and excellent 

 as is the advice that study in the field is absolutely necessary 

 to the young geologist, it is not possible for any but a few 

 to travel to ihe scenes vvhi-h are here described. .Accurate 

 photographs are, consequently, of the greatest importance, 

 and here we have a sure and safe guide. It is impossible 

 to select .my one portioii of the book as more deserving of 

 special notice than another. The Professor of Geology in 

 Cornell University has done his work well, and we have 

 much pleasure in calling attention to his book. — E. A. M. 



Hints to Meteorological Observers (prepared under the 

 direction of the Couiuii of the Royal Aleteorological Society, 

 by William Marriott, F.R.Met. Soc, Assistant-Secretary. 

 6th edition revised and enlarged with illustrations, pp. 70 

 with frontispiece; is. 6d.) — This valuable work is now 

 brought up to date, and enlarged and provided with excel- 

 lent illustrations, showing a great advance on the first edi- 

 tion of a quarter of a century ago. .A comparison of the 

 two will show the great advance made in meteorology 

 during that period, as evidenced by a short list of some of 

 the additions shown by a comparison between these two 

 editions. Not having a copy of the intermediate editions, 

 this is the only course open to us. This list includes such 

 familiar subjects as Sunshine Recorders, Self-Recording 

 Instruments, Kites, Phenological Observations, and Dines' 

 Pressure-Tube Anemometer, showing that these are either 

 new, or, at any rate, were too rare 25 )ears ago to be in- 

 cluded m a handbook designed for the use of the ordinary 

 meteorological observer. If there is one science which ap- 

 peals to a large class as an interesting and by no means 

 difficult or expensive way of increasing the world's know- 

 ledge. It would seem to be meteorology. The laborious 

 night watches and heart-breaking conditions of " seeing," 

 which press hardly on the astronomer, especially in later 

 life, arc almost unknown to the climatological ' observer, 

 who, if his habits are regular and his health "good, will find 

 little dilTiculty in maintaining an unbroken and, therefore, 

 valuable series of daily observations. To anvone looking for 

 worlv of this kind we can confidently recommend Mr. 

 M.arriott's " Mints," which contain practically all he can 

 want to know about instruments and their careful manipu- 

 lation, with ustful illustrations, tables, very much cnlarjjed 

 in the 6tli edition for reduction and computation of v.-irious 

 elements, conversion of scales, and so on, with a useful 

 glossary of meteorological terms, and many other features, 

 including as frontispiece the set of " cloud forms " with 

 names ,ind approximate altitudes (from Inwards' " Weather 

 Lore "), and as tail-piece Dr. Jenner's well-known 

 " Prognostics for Rain." 



The Birds of Hampshire and the Isle of Wight, by the 

 Rev. J. !•:. Kelsall, M. A., and Philip W. Munn (London : 

 Willierby .and Co., 1905). — County histories of this kind do 

 not, as a rule, form very interesting reading, while their 

 usefulness is extremely limited. The present volinne is, 

 however, a notable exeejjtion to this rule ; it may justlv be 

 claimed for it, indeed, that it is one of the best monographs 

 of its kind that has yet appeared. .\nd this because it con- 

 tains something more than the niere record of species oc- 

 curring, or extinct, within the limits of the county. On Ihe 

 contrary, its paf;es are richly stored with most interesting 

 matter glea.ied from the works of such celebrities as Gilbert 



