SCIENCE- G OSSIP. 



1^3 



rewritten and brought up to date, though we see 

 Messrs. Beck's and Messrs. Eoss's latest models 

 are evidently too recent to allow of their inclusion. 

 Amongst portable microscopes Swift's new model 

 also does not find a place. In our opinion, this 

 portion of the book is a great improvement on 

 the previous edition, and one prominent maker's 

 .stands in particular, previously entirely omitted, 

 :now receive ample treatment and praise. We can 

 only express our hearty agreement with the con- 

 cluding criticism of Continental stands, and wish 

 this could be brought to the notice of those who 

 are responsible for the undeserved favour which 

 Continental microscopes — -^q expressly except Con- 

 tinental objectives — obtain in certain quarters. 



Chapter IV. deals with accessory apparatus ; and 

 here we note a useful extension of the section 

 devoted to camerae lucidae. On p. 315 is a most 

 acceptable table giving the total and aplanatic 

 apertures and powers of the various condensers 

 now on the market, the most notable of which are 

 ■of quite recent date. It may, perhaps, not be futile 

 to hope that this table may bring home to some 

 enterprising opticians the advantage of putting 

 upon the market a condenser of moderate power, 

 say half an inch, with an aplanatic aperture con- 

 siderably higher than that of the Abbe achromatic 

 form, and of less cumbrous dimensions. The best 

 of these, so far, is Baker's fine condenser of 1 N.A., 

 with an aplanatic aperture of -95 ; but the power is 

 four-tenths of an inch, which is rather too high 

 for ordinary work, the field of illumination being 

 ■correspondingly circumscribed. Watson's " para- 

 chromatic " condenser is of still higher power, and 

 Swift's is higher still. On p. 319 a new feature 

 appears in a description of how to view the rings 

 and brushes shown by certain crystals under 

 polarised and convergent light. This might, we 

 think, with advantage have been widely extended. 

 It is curious that in no text-book is this subject 

 thoroughly treated, whilst the use of the calc-spar 

 plate, the quarter undulation plate, and the use of 

 the quartz wedge and other appliances of the petro- 

 logical microscope are left severely alone. 



Chapter V. deals with objectives, eyepieces, etc., 

 and our only criticism of this section would be that 

 English objectives scarcely receive their due meed 

 ■of recognition as compared with Continental ones. 

 We could mention several English J^-inch oil im- 

 mersions that are fully equal to those of Leitz and 

 Eeichert singled out for special praise. We have 

 noticed a few printer's errors in this chapter, and 

 the block representing fig. 334 is printed upside 

 •down. Chapter VI. deals with practical micro- 

 .scopy, and remains much as before. Chapter VII., 

 ■dealing with mounting, etc., is almost entirely re- 

 written and recast, and represents a notable im- 

 provement in what was before one of the weak 

 points of the book. For this, we understand from 

 the preface, Mr. A. B. Lee is largely responsible. 

 The new marshalling and explanation of methods, 



in place of the previous somewhat indefinite' 

 arrangement, is of much servicei ■ , 



The remaining seventeen chapters, save the last 

 two, deal entirely with plant and animal life. 

 These are, for the most' part, only altered where 

 later investigations have rendered a niodification 

 of the text necessary. For example, the. consider- 

 able amount of space devoted, as is to be expected, 

 to diatoms, contains an important modified state- 

 ment with regard to the formation of auxosjDores, 

 and as regards the movement of diatoms. The 

 chapter on Bacteria is also somewhat altered and 

 rearranged. It contains new illustrations from 

 Cruikshank and the two new plates already alluded 

 to in this notice. With reference to the repro- 

 duction of Infusoria, we note that Balbiani's 

 assertion as to there being a true sexual repro- 

 duction amongst these lowly organisms is now 

 deleted, and an appendix to this chapter gives in 

 full Mr. Eousselet's now widely-known method of 

 preserving and mounting Eotifers. The chapter 

 dealing with Sponges and Zoophytes contains some 

 new illustrations ; also a slightly-extended biblio- 

 graphy, which might with advantage have been 

 carried out with regard to the Mollusca, the Insects, 

 and Arachnids, the references to which are not at 

 all easy to obtain. Chapter XXIII. deals with the 

 application of the microscope to geological in- 

 vestigations, and the optical characters of minerals 

 receive further treatment, especially with regard 

 to their behaviour under polarised light with 

 reference to their axes of elasticity, their refractive 

 indices, pleochroism, etc. Chapter XXIV., dealing 

 with micro-crystallisation, the optical properties of 

 crystals, etc., is, perhaps unavoidably, incomplete ; 

 whilst micro-chemical analysis receives but a bare 

 allusion. In conclusion, we may add that the 

 tables forming the appendix, where altered at all, 

 are for their improvement. 



We heartily welcome the new edition of this 

 most comprehensive work, which under Dr. 

 Dallinger's editorship has far exceeded the 

 boundaries that Dr. Carpenter gave it, and which 

 in fulness of treatment, in scope, and in authority 

 is unapproached in any other country. — F. 8. S. 



Caprimulgus europaeus. — Near Pyrford Lock, 

 August 11th, I saw two boys, very much excited, 

 trying to stone a nightjar, which was hawking in 

 the early dusk, uttering its shoit cry, but not trying 

 to avoid the stones. I see that Mr. H. Kirke 

 Swann, in his " Handbook of British Birds," p. 100, 

 says "the vibrating and sustained 'jar' or ' churr ' 

 ... is probably never uttered on the wing." The 

 cry my wife arid I heard was a short, eager, single 

 cry, given at frequent intervals. I may add that 

 I explained to the boys the wonderful anatomy of 

 the bird's gape and throat, also its usefulness as an 

 insectivorous bird. The stone-thrower dropped his 

 missile, and told me that there were thirteen of 

 these "jackdav.'s" there on the night previous. 

 Mr. Derisley, of Wisley Farm, confirms the fact 

 that they are numerous in the neighbourhood. — 

 B. AsMngton Bullen, F.L.S., Axeland Pa/rk, Horley. 



