November 28, 1867. J 



JOURNAL OF HORTICULTUBE AND COTTAGE GARDENER. 



403 



of Iho Anstralian species of Bnprestidffl, described by the Rey. F. W- 



Hojtc, now in the Oxford Museum. 



Mr. 1''. W. Wood lead a nuiuoir on the variation of colonr in chrysa- 

 lids, dependent upon the position in which they are placed. The author 

 exhibited a hir^e number of cbrysalid.s of the Hwallow-tail and lar^je and 

 small Cabbage HutterHies, varyinR Rreatly in colonr, some, which had 

 been confined iu a box with the inside blackened, being nearly black, 

 while others were brif^ht green, and some nearly colourless, the green 

 ones having been found on or covered by leaves, whence the author in- 

 ferred that the variati.iu in colour served as a defence against the 

 enemies of the insect by preventing them from seeing it. Mr. Bond, 

 however, denied tliat the colour of the locality where the chrysalis 

 state is effected, docs in the least alToct the colour of the chrysalis 

 itself, mentioning that he had found three chrysalids of the Orange- 

 tipped Buttcrriy of different colours on a single plant of the common 

 Rocket. 



Mr. Pascoe coromnuicatcd a note on the collecting of the common 

 Cockchafer in Hwilzcrland, for obtaining a supply of grease used for 

 cart wheels, it'c. 



A memoir was communicated by W. C. Hewitson, Esq., containing 

 descriptions of a number of new and beautiful species of Butterflies, 

 from Nicaragua, Kcuador, t^uito, &c. A paper by the Rev. D. C. 

 Timins, was also read, containing a monograph of the beautiful genus 

 Thais, of which the author enumerated seven species, found iu the 

 south of Karope and north of Africa. 



NEW BOOKS. 



Iiitwihictorij Text Book of Gcoloyy. Seventh and enlarged 



Edition. 

 Advanced Text Book of Gcalori;!, Vcscriptloc and Industrial. 



Fourth Edition, revised and enlarged. 



By David Pace, LL.D., &c. Blackwood and Son.?. 



We know of no mental dejection so fatal to acquiring a know- 

 ledge of any science as that caused by a feeling that you are 

 not strong enough to master it — a dejection usually induced 

 and strengthened by finding that the books you have to study 

 are dry, repulsive, and entangled. You know they contain the 

 solid materials of the edifice, but you feel as if the master 

 builder had not rendered them smooth, nor put them into the 

 positions to facilitate your fixing them iu their right place, and 

 retaining them there, and that you never could succeed iu 

 doing so. By no one is this dejection more usually felt than 

 by the student of geology, and we opened the volumes now 

 before us fearing that they would have the radical defect of 

 their predecessors. We had a better hope when we saw that 

 one volume had reached its seventh edition in less than twice 

 as many years, and that the other volume had entered its 

 fourth edition in a still shorter time. That hope was realised 

 by placing the " Introductory Text Book " in the hands of one 

 who had no knowledge of geology, and by our observing that 

 he continued to read it until the night was far advanced, and 

 that ho renewed his perusing in the morning. 



The test was truthful, for we find that both Mr. Page's 

 volumes are the most lucid instructors in geology we ever read. 

 They present well-combined agreeableness, fullness, and ac- 

 curacy of detail. 



Every science must have a nomenclature to facilitate de- 

 scription, and when such nomenclatures are employed un- 

 explained iu introductory books, they weigh down the student, 

 by fatiguing his memory in the oft-foiled effort to retain un- 

 couth, and to him unintelligible names. Dr. Page has avoided 

 this ; ho uses the geological nomenclature sparingly, and where 

 he uses it he interprets it. We remember the disgust of a 

 student who could not find an answer to his inquiry, " Why is 

 it called the Oolite system'.'" Dr. Page in one sentence ex- 

 plains it. " It derives its name from the rounded concre- 

 tionary grains which compose many of its limestones — these 

 grains resembling the roe or egg of a fish, oon, an egg, and 

 lithos, a stone." Such explanations aid the memory, for that 

 is best remembered which is best understood. But Dr. Page 

 has adopted another help to the memory, by appending to each 

 chapter a " Recapitulation," being a succinct compendium of 

 the chapter's contents, acting as an examination and refresher. 

 It is needless to particularise the scientific details and ar- 

 rangement of the two volumes, for they are in unison with 

 those of the best and most recent researches, but as what is 

 meant by " industrial " geology, may not bo apparent, we will 

 give one illustrative extract, and it shall bo from the " Ad- 

 vanced Text Book," relative to the strata we have already 

 noticed — the oolitic. 



*' Some of the oolitic strata, like those of Bath and Portland, form 

 exC'Ueut building-stone, and are extensively used for that purpose iu 



the south of England. The well-known Caen stone is also a member 

 of the same group ; while paving-stones and roofing-flags are obtained 

 from some of its fissile sandstones iStouesfield, CoUywestou, &c.), and 

 also from those of the Wcalden at Pnrbeck, and other parts of Sussex. 

 Both the lias and oolite limestones are largely quarried for mortar ; 

 and the former, which generally contain from SO to 90 per cent, of 

 carbonate, with clay and oxide of iron, when well prepared, famish an 

 excellent hydraulic cement. Marbles of varions quality are procured 

 from the lower beds of the Weald, in Sussex ( ' Sussex or Petworth 

 marble ' ), and in Purbeck ( ' Purbeck marble ' I ; and also from some 

 of the coralline and shelly oolites, as atWhicbwood Forest, in Oxford- 

 shire, whence the term 'Forest marble.' The finer kinds of lias re- 

 ceive a poUsh, and have been tl-ied with indiffureut success for litho- 

 graphic blocks — the chief supply of which has long been obtained from. 

 the oolitic beds of Solenhofen and Dichstadt, in the centre of the Ger- 

 man Jura. The pyritic clays and shales of the Yorkshire lias yield 

 on proper treatment sulphate of alumina (the tdiim of commerce), 

 which at ono time was also obtained from the ICimmeridge clay : and 

 during the sulphur monopoly of Sicily, several patents were taken for 

 the extraction of sulphur from the same pyritic (snlphuret of iron) 

 liassic strata. Fuller's earth — which is essentially composed of silica, 

 alumina, and about '2-1 per cent, of water, and like other aluminous 

 marls possesses in a high degree the pi-operty of absorbing gi-ease — is a. 

 product of the upper oolite, and was at one time extensively used in 

 the cleansing and scouring of woollens. Iron was at one time ex- 

 tracted from the nodules and pisiform iron-sands of the Wealden ; 

 ironstone of workable quaUty occurs in the ooUtes of Yorkshire, and 

 has long been gathered along the shores of the same county from the 

 waste oif the lias cliffs. The great ironstone treasury of the system, 

 however, is the ' Lias band ' of Yorkshire. ' Within the last few 

 years,' says Phillips, ' this band, often 16 feet thick, and of good 

 quaUty, has been worked to great advantage at Eston, and other points 

 in Cleveland [where, wo may add, it is creating quite a revolution in. 

 the appearance and iudustn' of the country], as well as at Gromon); 

 Bridge, in Eskdale. The area under which this bed inaij be worked 

 measures some hundreds of square miles, with an average produce o£ 

 •2(1,000 to 50,000 tons per acre. It dies out southwards, and vanishes 

 about Thirsk ; but there other ironstones acquire value in the ooUtic 

 series above.' A bituminous shale, or brown shaly coal, with a specific 

 gravity of about 1..S2, and burning w-ith a dull smoky flame, occurs in 

 the Kimmeridge clay, under the name of ' Kim coal,' and has been 

 worked for the extraction of parafiine, &c. ; and jet (which is simply 

 altered coniferous wood) is found both in tho wealden and lios. Seams 

 of coal, which are sometimes workable, occur in the system, as iu the 

 oolite at Gristhorp, in Yorkshire ; at Brora, iu Sutherlandshire ; a t 

 several places in the German wealdeus, fiom 2 to 3 feet thick ; on the 

 southern flanks of tho Caucasus ; iu the East India ooUtes ; and 

 notably at Richmond, in Virginia, where a valuable field extends about 

 twenty-six miles in length, and from four to twelve in breadth." 



DENDROBIUM DENSIFLORUM. 



Although it blossoms at a time when flowers are scarce, 

 this handsome plant is not so much cultivated as it deserves 

 to be, as nothing can well surpass a plant which we have now 

 in flower, there being tweuty-four spikes of fully-expanded 

 flowers, each spike as large and three times as dense as that; 

 of the Laburnum, which they somewhat resemble. The plant 

 is also of compact growth, the highest portion not being more 

 than 1.5 or 18 inches above the pot, while it is upwards of '2 feet 

 through, and the beautiful racemes almost entirely cover it. 

 The colour, as is well known, is a sort of apricot yellow. Be- 

 sides the spikes now out, about a dozen others are more or less 

 advanced, giving promise of a lengthened period of flowering. 



An ordinary stove seems to suit this Dendrobium very well, 

 as the plant described has never been kept so hot as recom- 

 mended for some of the same genus ; still, it is kept warmer 

 than those for which cool treatment is advised. As flowers 

 iu November are not over-plentiful, a handsome one, such as 

 Dendrobium densiflorum is, cannot be too highly recommended. 

 — J. E. 



GISHURST COjMTOUND. 

 EE.\riNr, my Journal of Hokticultuhe of October 31st, I 

 noticed Mr. Pearson's trials of scale remedies, and regretted, 

 if he desired to make a fair comparison between different 

 specifics, that he only sponged with Gishurst compound, while 

 he dipped — by far the most effectual mode of treatment — in 

 the insecticide. I also regretted, as his " boys were dis- 

 gusted," that the Gishurst solution had not been made, as 

 recommended, forty-eight hours before use, by which strong 

 smell is removed. I then, on November 7th, read " T. E.'s " 

 report of many remedies which his great experience has led 

 him to adopt, mentioning Gishurst only against American 

 bUght on Apple trees. In th» number for November •21st Mr. 



