11G 



HARDWICKE'S SCIENCE- GOSSIP. 



washed in water, and then placed between the 

 leaves of a book made of bibulous paper to dry. 

 After this the specimen to be mounted was soaked 

 iu turpentine for half an hour, and then placed on 

 writing-paper to drain. In the meantime the bottle 

 containing the Canada balsam had been heated in 

 an oven for half an hour, so as to render the medium 

 liquid enough to be removed by means of a pointed 

 cedar stick, and the estimated quantity placed in 

 the centre of each of a number of glass slides. The 

 balsam becomes immediately solid, and the specimen 

 of the moss drained from the superfluous turpen- 

 tine, is laid on the top, on which the circle of thin 

 glass is carefully placed, and slightly pressed with 

 the finger. The slide is then committed to the em- 

 brace of one of Smith's mounting instruments, and 

 held over a fire to liquefy and diffuse the balsam. 

 After this, the slide is removed, and placed for a few 

 hours in an ordinary wire clip. The glass is filially 

 cleaned with turpentine, and the black ring, after a 

 time, put round by means of a turntable. The 

 mosses already mounted have a very beautiful and 

 characteristic appearance : a collection thus prepared 

 will be valuable and interesting. Many of them 

 polarize in a remarkable manner, especially as 

 regards the nerves, tips, and borders of the leaves- 

 Most of the specimens operated upon have been 

 of this season's growth, but a few have been dried 

 for many years. In the latter case, the plant is of 

 course revived by immersion in water. Should 

 this notice meet the eye of any collector of British 

 mosses, who can send me specimens of rare or local 

 species of Hepaticse, I shall be most happy to return 

 a portion, mounted for the microscope, or to ex- 

 change other slides for them. A small piece will be 

 sufficient, if possible iu fructification, either dried or 

 recent, although the latter will be preferred. — 

 Henry Knight, Belfast. 



GEOLOGY. 



Sand Dunes and Blowing Sand is the title of 

 a paper in the last number of the Popular Science 

 Review (which this quarter is unusually good). It 

 is written by Mr. W. Topley, E.G.S., of the Geo- 

 logical Survey, and whilst dealing with an important 

 geological question, is written in an exceedingly 

 agreeable and even attractive style. 



Structure of Columnar Basalt. — The in- 

 teresting abstract of Mr. R. Mallet's paper on the 

 Structure of Columnar Basalt, in the March number 

 of Science-Gossip, has brought to my mind what I 

 once noticed on the bank of one of the grand rivers 

 of Burmah ; and though it does not actually touch 

 the question discussed by Mr. Mallet, yet it may be 

 of some interest to your readers. Almost the whole 

 of British Burmah, — certainly the whole of the 

 province of Pegu, is one vast alluvial plain, built up 



by the accumulation of silt brought down from the 

 higher lands by the rivers Irrawaddy and Sittang 

 principally. The Salween, further to the eastward, 

 having a basin of its own, has not contributed so 

 largely to the building up of the alluvial deposit. 

 The quantity of silt carried down in the water of 

 these rivers, especially while in flood, though not 

 equalling what I have seen in the water of the Nile, 

 is very remarkable, and has often been to me very 

 suggestive of the vast changes on the surface of 

 the earth, which are being constantly and slowly 

 wrought out before the eyes of those who have eyes 

 to observe such things, by agencies ever at work 

 around us. The Buddhist tradition of the origin of 

 Pegu seems really to have been imagined by some 

 one who watched what was going on around him. 

 After hovering for ages over a waste of waters, the 

 sacred hansa or goose, with its gander, noticed a 

 tussock of grass appearing out of the water. "Weary 

 they settled upon it, but the foothold was so narrow 

 that the goose had to perch upon the gander's back. 

 They then flew away, nor did they revisit this 

 spot till after the lapse of a whole kalpa : a fabulous 

 age of untold thousands of years; when, lo! there 

 was room for them to rest side by side ; and so on 

 from kalpa to kalpa, at each returning visit find- 

 ing the space widened, till at last it was a province, 

 with its cities and their inhabitants. That province 

 is now the most fertile part of British Burmah, and 

 I have often, while navigating the rivers that inter- 

 sect it, remarked with interest their perpendicular 

 sections, cut out by the rapid waters, of ten, twelve, 

 fifteen, or perhaps more feet of purest alluvium ; 

 the particles of which the silt is composed being, 

 as will be readily understood, the smallest imagin- 

 able. Landing one evening, in the course of a boat 

 voyage down the Sittang, on a bank of silt of con- 

 siderable depth, which had been left too recently by 

 the river to be as yet clothed with vegetation, but 

 which yet had been, owing to the fall of the water- 

 level, baking in the tropical sunshine for perhaps 

 some weeks, I found the surface quite hard and 

 dry ; but the action of the sun in evaporating the 

 moisture, aud thereby causing contraction, had 

 caused a number of vertical or quasi-vertical 

 fissures to open up, of very considerable depth, 

 extending indeed, so far as I could ascertain, quite 

 down to the bottom of the bed of recent silt. These 

 fissures, running in various directions, reticulating 

 the whole surface of the mud-bank, had cut it up 

 into pretty equal and roughly hexagonal, or pen- 

 tagonal figures, such as at once to suggest to my 

 mind the section of columnal Lbasalt. These 

 columns of mud averaged rather less than a foot 

 diameter; the fissures between them gaping to two, 

 three, or even four inches wide. The tendency of 

 these columns to split up in a direction perpen- 

 dicular to their axis, so well described in Mr. Mallet's 

 paper in the case of basalt, was occasionally, though 



