110 



HARDWICKE'S SCIENCE-GOSSIP. 



[June 1, 1S6S. 



MICROSCOPY. 



The Lead Tree. — A common amusement of 

 boyhood is the pleasing experiment of the lead-tree. 

 As a microscopic object, it may possibly be new to 

 some of your readers. The apparatus which I have 

 used for its exhibition is very simple. I take one 

 of the square rings that are made for forming cells, 

 break off oue of the four sides, and cement a piece 

 of thin glass on each side, to form a deep narrow 

 cell, — in fact, it is a zoophyte trough ; then cut a 

 thin strip of zinc, and bend it so as to drop into the 

 cell. Put as much acetate of lead, powdered, as 

 will lie on the point of a penknife into the cell, and 

 fill it up with water by means of a dipping tube. 

 Insert the strip of zinc, and view it immediately 

 with an inch or half-inch object-glass. As soon as 

 the zinc is immersed in the lead solution, beautiful 

 fern-like branches begin to open out from it on all 

 sides. The object may be viewed by either 

 transmitted or reflected light ; the latter perhaps is 

 the best. The theory of the action is thus stated in 

 Eownes' Manual of Chemistry : — " When a piece of 

 zinc is suspended in a solution of acetate of lead, 

 the first effect is the decomposition of a portion of 

 the latter, and the deposition of metallic lead upon 

 the surface of the zinc; it is simply a displacement 

 of the metal by a more oxidable one. The change 

 does not, however, stop here. Metallic lead is still 

 deposited in large and beautiful plates upon that 

 first thrown down, until the solution becomes 

 exhausted, or the zinc entirely disappears. The 

 first portions of lead form with the zinc a voltaic 

 arrangement of sufficient power to decompose the 

 salt ; under the peculiar circumstances in which the 

 latter is placed, the metal is precipitated upon the 

 negative portion — that is, the lead — while the oxygen 

 and acid are taken up by the zinc." The effect may 

 also be witnessed by putting a drop of the solution 

 of lead upon a hollowed glass slip, and dropping in 

 a few zinc filings. — It. H. N. B. 



Myriapod. — Sir John Lubbock has found a 

 curious Myriapod, common in company with 

 Springtails amongst old leaves &c, which has 

 hitherto been overlooked. He calls it Pauropws 

 Huxleyi ; and another species, less common, he 

 names Pauropus pedunculatus. The first of these 

 is only -fa of an inch in length, and is therefore 

 quite a microscopic object. 



British and Foreign Galls. — The lamented 

 death of Mr. W. Armistead, who was pursuing this 

 study in the prospect of publishing a work on the 

 subject, is in some measure compensated by bringing 

 another worker into the field. Any correspondent 

 willing to assist with specimens are requested to 

 communicate with Mr. Albert Midler, 2 Camden 

 Villas, Penge. 



NOTES AND QUERIES. 



" There is a God," all nature cries ; 



A thousand tongues proclaim 

 His arm almighty, mind all-wise, 

 And bid each voice in chorus rise 



To magnify His name. 



Thy name, great nature's Sure divine, 



Assiduous we adore ; 

 Rejecting godheads at whose shrine 

 Benighted nations blood and wine 



In vain libations pour. 



Yon countless worlds in boundless space 



Myriads of miles each hour 

 Their mighty orbs as curious trace, 

 As the blue circle studs the face 



Of that enamelled flower. 



But Thou, too, madest that floweret gay 



To glitter in the dawn : 

 The Hand that fixed the lamp of day, 

 The blazing comet launched away, 



Painted the velvet lawn. 



" As falls a sparrow to the ground 



Obedient to Thy will," 

 By the same law those globes wheel round, 

 Each drawing each, yet all still found 

 In one eternal system bound 



One order to fulfil. 



By the late Lord Brougham. 



Claytonia perfoliata(p.115). — I am not aware 

 how long this plant hasbeeu introduced intoEngland, 

 but I can bear testimony to the fact of its having 

 "escaped" as long as five-and-twenty years ago, 

 the late Mr. W. Borrer having pointed it out to me 

 in the year 1843 on Henfield Common, where it was 

 growing in an apparently wild condition near a 

 small stream. I think, but am not quite certain, that 

 Mr. Borrer spoke of it as having been there many 

 years. In the new edition of "English Botany" it is 

 mentioned as being thoroughly naturalized in many 

 places in Englaud — Henfield, Sussex, &c. — IF. IF. 

 Spicer, Clifton. 



Claytonia perfoliata grows in large quantities 

 in a wood in Chatsworth Park. This plant is not 

 mentioned in "Sowerby" (2nd edition), but it will 

 be found in "Baxter," and in "Sowerby" (3rd 

 edition).— F. P. IF. 



Springtails.— In the last part of the Transac- 

 tions of the Linncan Society Sir John Lubbock 

 contributes a third paper on the Thysanura, in 

 which is included descriptions of seventeen species 

 of British Podura, and allied genera. 



