JCLY 7, 1882.] 



KNOWLEDGE • 



91 



any limestone they may meet with ; the elVervescence which 

 results when a drop of this acid is placed on any rock is a 

 sure sign that it contains a large proportion of carVionate 

 of lime. Lastly, a poclxt magnifier, provided with two 

 lenses, will be needed to examine tinely-graiiu'd rocks, or 

 to scan their surface for minute fossils. 



Let no one, however, think that all the aliove articles 

 a-e indispensable to good geological work : the tact is that 

 ■while they are all uS'-fiJ, they are none of them absolutely 

 n^c'ssaty. I have known a working-man, armed with 

 nothing better than a coal-pick, to acquire a knowledge of 

 the rocky structure of the district in which he lived, which 

 has enabled him to lend valuable assistance to the Govern- 

 ment surveyor. 



App.\KATrs FOR Home-work. — A good microscope is 

 much to be desired, and I can recommend the instrument 

 specially designed for geological work by Mr. Swift. It is 

 now very much the fashion to make thin sections of rocks, 

 especially the igneous rocks, so as to determine, micro- 

 scopically, the minerals of which they are composed ; an 

 excellent machine has been invented for this purpose by 

 Mr. Jordan ; but this costs from .£8 to o£10. Ky cement- 

 ing chips of rocks to strips of glass, it is possible to rub 

 them down by hand — lirst on an iron plate with emery and 

 water, and afterwards on a waterof-ayr stone with water 

 only, until they acquire the necessary thinness and trans- 

 parency ; the process is a tedious one, but a Lancashire 

 working-man has in this way made hundreds of beautiful 

 sections of the fossil plants of the coal-measures. A 

 cahiiiel to keep specimens in may often be picked up 

 second-hand ; the drawers should measure about 20 in. bj' 

 LJ in., and should vary in depth from U in. to 1 in. 



Books. — The best general text-book for beginners is 

 Lyell's " Student's Elements of Geology " (Murray) ; to 

 this we may add Rutley's " Mineralogy " (Murby), and 

 " Study of Rocks " (Longmans). 



In'.\.mixg of Specimeks. — Book knowledge alone is of 

 little real value to the geologist. He must learn to recog- 

 nise (1) minerals, (2) rocks, (3) fossUs. To do this it is 

 absolutely necessary to carefully examine correctly-named 

 specimens. The dweller in London must visit the geo- 

 logical museum in Jermyn-street and the new Natural 

 History Museum at South Kensington for this purpose. 

 Named collections, or single specimens, are sold by many 

 dealers, among whom I have long known Mr. Gregory 

 (Charlotte-street, Fitzroy-square) to be thoroughly reliable 

 and trustworthy. By far the best work on the study of 

 fossils is Professor Nicholsons " Pal.Tontology " (Black- 

 wood), but no one must expect to make much progress in 

 the study of fossil shells — or, indeed, any extinct forms — 

 unless they first study, to some extent, the li\-ing species. 



In my recently-published Viook on " The Geology of the 

 Counties of England " (Kelly A- Co.), I have given lists of 

 the more important books and papers on general geology ; 

 and have also proiixed lists of local papei-s, maps, and 

 books to the articles on each county. 



There are two great libraries of geological iKjoks in this 

 country, and of each of them a catalogue has recently been 

 published. Tlio library of the Jermyn-strrct JIuseum 

 includes about 28,000 volumes. To consult the books, per- 

 mission must l)e obtained from the curator, Mr. F. W. 

 Rudler, to whose kindness and courtesy I, like many other 

 workers in geology, can bear willing testimony. 



The library of the Geological Society of London is 

 lodged in Burlington House ; it may be inspeoted by ol>- 

 taining an introduction from a Fellow. Provincial libraries 

 are, almost without exception, extremely deficient in geo- 

 logical works. Even the volumes of the Pala?ontographical 



Society, in which all the British fossils are Uing figured 

 and described, are hardly to be met with on the bhelves of 

 one public library out of ten ! Of the " Transactions " 

 and other publications of the local scientific societies of 

 Great Britain, I do not believe there is a complete set 

 in any library whatsoever. 



But, besides the study of specimens at home, tliere is 

 much geology which can only be learnt by looking at the 

 rocks on a grand scale in the field. It was said of Mur- 

 chison that " he had a fine eye for a countrj-,'' and it is the 

 acquisition of this power of reading the surface features of 

 any landscape that we should strive to obtain. No district 

 can be uninteresting, or can fail to furnish useful employ- 

 ment to a true geologist The pleasure of understanding 

 the causes which have produced our English scenery 

 doubles the delight arising from its contemplation, and 

 when, after viewing the rocks from a distance, we interro 

 gate them closely in the quarry or on the hillside, we shall 

 learn from them the hi.stor\- of the past, told without possi 

 bility of error, and with a fulness according to our powers 

 of interpretation. 



EXCxLISH SEASIDE HEALTH-RESORTS. 



By Alfred Haviljlxd, MR.C.S., F.R.M.C.S. Lond. 



CLASSIFICATION" (Conlimud from page .53). 



BEFORE leaving the subject of the effect of latitude 

 on the climate of the sea-coast, it will be well to 

 refer to an opinion entertained by many against the more 

 northerly health-resorts. It is supposed that because they 

 are so many miles north of London and other large towns, 

 that they necessarily must be cold, exposed, and unfitte<l 

 for some cases — for instance, the consumptive. A more 

 erroneous notion could not be conceived ; moreover, it is one 

 that operates prejudicially in two ways : it prevents many 

 from deriving benefit from their pure and bracing climates, 

 and acquiring that physical and mental tone so conducive to 

 the prevention of the development of their latent disease ; 

 whilst it misleads them to the more Southern resorts, thi- 

 mild, balmy atmosphere of which is often a short salvation 

 to those whose disease is developed, but impotent to give 

 the necessary vigour to the young, who hope to conquer 

 their disease, and eventually li\e anywhere. That the 

 Northern part of the English coast, and especially on the 

 north-eastern side, has a climate in whicli consumption 

 (Lat. Phthisig) does not thrive, may be shown by the low 

 mortality from this cause, which characterises this part of 

 the country, and forms so remarkable a grotip in the map 

 whereon the geographical disti-ibution of this disease is 

 portrayed. 



If we look at a map of England, we sliall see that its 

 triangular form favours, in a striking manner, the pre- 

 servation of the insular character of its climate, for it 

 tapers from its southern base, or from the fifty third to the 

 fifty-fifth degree of north latitude, and thus enables the 

 seas on its western and eastern coasts to approach each 

 otlier, and to increase the insularity of this area almost in 

 the direct ratio of its receding from the south. If we enclose 

 England within an area, the limits of which are defined by 

 the longitudes ."•^ 4.")' W. ai\d 1^ ItV K (those of the Land's 

 End and Lowestoft), and the latitudes .lO^ and .'hV N., and 

 divide it into six interl.ititudinal zones or belt.s, we shall 

 be able to judge, accurately enough for our )>urpose, as to 

 the relative proportion of land to sea that obtains within 

 each zona 



Such an area, if the width at the northeni Iwundnry \>e 

 made equal to the southern, instead of following the 



