HARDWICKE'S SCIENCE-GOSSIP. 



137 



volcanic rocks. 5. Fine foliation is well developed 

 among the strata above the conglomerate as well as 

 in the volcanic group below. 



Professor Bonney thought that on the whole the 

 conglomerate made a good base for the Cambrian ; 

 and he felt certain that whatever the so-called 

 Dimetian might be, it was older than the Cambrian 

 conglomerate. 



Professor Geikie said that Dr. Hicks's views as to 

 the remanie character of the tuffs alternating with 

 the conglomerate were contradicted by the careful 

 study of Drs. Zirkel and YVichmann, and M. Renard. 

 Dr. Hicks had been recently to St. David's, but he 

 was quite unable to produce a pebble of Dimetian 

 from the Conglomerate. He controverted Dr. 

 Hicks's views as to the section at Ogof-llesugn. He 

 stated that the diabase dykes cut through both the 

 granite and the Cambrian conglomerate of the 

 district, though they are most abundant in the 

 former. In reply to Professor Bonney, he stated 

 that microcline was regarded by continental workers 

 as characteristic of granite rather than of gneiss. He 

 asserted that none of the conclusions of his paper had 

 been shaken by the discussion. 



MICROSCOPY. 



Germination of Fungus Spores under the 

 Microscope. — In reply to Mr. G. H. Wasse, inquir- 

 ing for information on this subject, I think that the 

 use of a damp chamber deserves at least a trial. It 

 would no doubt serve to keep the pabulum moist and 

 would maintain the damp atmosphere, which seems 

 to forward the growth of all Cryptogams. The damp 

 chamber devised by the Rev. Mr. Dallinger, and used 

 by him and Dr. Drysdale in their well-known 

 researches on the development of Monads, is the most 

 effective and the simplest of its kind. The following 

 description is taken partly from Mr. Dallinger's 

 article in the March number (1874) of the " Monthly 

 Microscopical Journal " and partly from Mr. Saville 

 Kent's version in his "Manual of the Infusoria" 

 {vol. i. p. 116). Its foundation consists of a plain 

 glass stage, ^ of an inch thick, so fitted as to slide 

 on in place of the ordinary sliding stage of a Powell 

 and Lealand or Ross stand. It is thus susceptible of 

 the mechanical motion common to those stages. 

 The thickness is too great to work through with 

 achromatic condenser and high powers, and therefore 

 a circular aperture is cut through in the centre and a 

 good piece of thin glass fixed over it with Canada 

 balsam. At the end of an arm projecting from the 

 left-hand anterior corner of the stage there is a socket 

 into which a glass vessel, if -2 inches deep, drops. A 

 piece of good new bibulous paper is laid on the stage, 

 coinciding with it in form, but slightly smaller and 

 with a tongue-like projection that lies along the arm, 



and dips into the glass reservoir at the end. A 

 circular aperture of greater diameter than the cover- 

 glass intended to be used, must be made in the 

 centre of the paper, and then the glass vessel filled 

 with water and the paper moistened. The fluid to 

 be examined is then placed on the centre of the thin 

 glass and covered, if necessary. The bounding walls 

 of the chamber are represented by a piece of glass 

 tubing l£in. in diameter and fin. in length, over one 

 end of which a piece of thin caoutchouc is firmly 

 stretched and a small hole made in its centre. The 

 bottom edge of the tube must be carefully ground. 

 This is placed on the stage with the caoutchouc 

 upwards, and the hole in it over the centre of the 

 cover-glass. The objective is now racked down 

 through the small hole and adjusted to focus. The 

 caoutchouc should be thin enough to afford no impe- 

 diment to the action of the fine adjustment, when it 

 will be seen that it clasps the object-glass firmly 

 round its central perforation, and the pressure from 

 the under edge of the chamber on the blotting-paper 

 so that little or no air is admitted, while if the under 

 edge of the chamber be carefully ground it will suffer 

 the stage, paper and all, to move under it when the 

 milled heads for working the mechanical stage are in 

 action. As I have neither mechanical stage, 

 achromatic condenser, nor very high powers, I have 

 an ordinary glass slide 3 X 2 Hn. such as would be 

 used for mounting large sections on, and I have 

 cemented to one corner a strip of glass which pro- 

 jects beyond the stage of the microscope, and is then 

 bent down at right angles so as to dip into a small 

 jar of water. A centrally perforated piece of blotting 

 paper with a strip from one corner hanging over into 

 the water is placed on the slide, and upon that a deep 

 glass cell iyjjin. in diameter, which can be procured 

 with both edges ready ground, a piece of thin 

 caoutchouc is easily tied over one end. Working 

 with medium powers I have been able to keep some 

 specimens of pond-life under observation, unfortu- 

 nately not continuous, for some length of time. — 

 E. J. Bles. 



Embryological Specimens for the Micro- 

 scope. — The new and fertile field of research opened 

 up by the development of the science of Embryology 

 has attracted numerous enthusiastic workers. All 

 such will be glad to hear that Messrs. Sinel&Co., of 

 Jersey, have commenced to issue slides illustrating 

 the embryology of marine life. Their situation gives 

 them splendid command of the most fertile marine 

 gathering grounds in the British Islands. We have 

 carefully examined the slides sent out, and are happy 

 to be the means of strongly recommending them to 

 our readers. The specimens are carefully named, and 

 mounted in a new preservative which admirably 

 retains the beauty of form and structure of the most 

 delicate of organisms. We understand that the happy 

 thought of introducing these specimen in this state 



