194 



SCIENCE. 



[Vol. XXII, No. 557 



Dr. Van Heurck's book is in tlie line of ttis change of 

 relation. Its purpose is a survey of microscopical science 

 from its technical, or, perhaps we should say, manipula- 

 tive side. Although the language into which the work is 

 translated is seldom wholly easy and natural, and occa- 

 sionally becomes even awkward and obscure, the author 

 may feel that, on the whole, his subject is presented to 

 English readers in an interesting and attractive form. 

 Dr. Van Heurck has long been known as a patient student 

 of certain difficult problems in interpretation and a 

 diligent cultivator of lines of microscopical work calling 

 for expert skill in the handling of accessories, and it is in 

 these directions that his book is strongest and most com- 

 plete. We should hardly be justified, however, in char- 

 acterizing his work as a symmetrical and systematic resume 

 of even the mechanical side of what is commonly known as 

 microscopy. In truth it seems to us to be somewhat lack- 

 ing in order and in equality of treatment of its various 

 topics. It is in a measure a record of the author's own 

 contributions to the progress of his favorite department 

 of learning and therefore of necessity bears an evident 

 personal stamp. The pride which he feels in his long ex- 

 perience and creditable achievements doubtless affects to 

 some extent his sense of proportion, so that points to 

 which he has himself happened to give particular atten- 

 tion are at times accorded what we may regard as a little 

 undue prominence. Thus, for example, we are inclined 

 to think too much s]3ace is given, and too much import- 

 ance attached, to the subject of electrical illumination 

 (pp.109-117), and that the praise bestowed upon the stand 

 devised by Dr. Van Heurck (pp.224-232) is rather more 

 unqualified than is appropriate to the circumstances under 

 which it aj)pears. One may reasonably question his as- 

 sertion that "electrical incandescent illumination is su- 

 perior to any other kind of illumination"' for the micro- 

 scope, and may well doubt whether he is fully justified in 

 pronouncing his own stand "a perfect instrument." But 

 these criticisms need not be taken as any disparagement 

 of Dr. Van Heurck's authority on questions of construc- 

 tion and manipulation. In these matters, as we have al- 

 ready said, his knowledge and ability are generally con- 

 ceded, and the novice will not go far astray in following 



his advice. If there is any fault to be found with his 

 guidance it is likely to be that in places it is too profuse 

 and painstaking. Thus, in common with most other 

 writers of microscopical text-books, he appears to us un- 

 necessarily lavish in the space devoted to the mere cat- 

 aloguing of the instruments of many makers, which differ 

 from one another mainly in pattern ; and we feel disposed 

 to ask whether a general description of the essential parts 

 and qualities of a good stand, in each class, would not an- 

 swer every purpose and enable the author to dispense 

 with some pretty bad borrowed woodcuts. While on this 

 subject, we venture to suggest, also, that much of the de- 

 tails under the heading "The Photographic Processes" 

 might be omitted with profit, since they rehearse particu- 

 lars which one may obtain in any manual of photography 

 and which are not peculiar to photo-micrography. In- 

 deed, some of the directions seem to be merely extracts 

 from a general hand-book, as, for instance, where we are 

 told (p. 272) that in development we shall get "first the 

 sky and the high lights." 



Beyond those portions which deal with the handling of 

 the instrument and the preparation of si^ecimens, this 

 work undertakes to cover the theory, the history and the 

 literature of the microscope. The chapter devoted to 

 " Experiments on the Application of Dr. Abbe's Theory of 

 Microscopic Vision " is a reproduction of Mr. J. W. Ste- 

 phenson's very valuable paper presented to the Royal 

 Microscopical Society in 1877, Avhich Dr. Van Heurck has 

 edited with a view to making it conform to the modifica- 

 tions which Prof. Abbe's views have since undergone. 

 The chapter on " The Microscope in the Past and in the 

 Future " is an abridgment of the Cantor Lectures of Mr. 

 John Mayall, Jun., delivered in 1885. The chapter 

 headed " The Microscopist's Library " is an incomplete 

 list of ]periodicals and books not always up to date. 



Notwithstanding the fact that the work before us is 

 rather too sumptuous and bulky for everyday use by the 

 student, it will doubtless prove a welcome addition to the 

 librai'y of the scientific amateur, and will perform a use- 

 ful part in the promotion of interest in the instrument of 

 which it treats. 



FOSSIL RESINS. 



This book is the result of an attempt to 

 collect the scattered notices of fossil resins, 

 exclusive of those on amber. The work is of 

 interest also on account of descriptions given 

 of the insects found embedded in these long- 

 preserved exudations from early vegetation. 



By CLARENCE LOWN and HENRY BOOTH. 



13°. $1. 



R. D. C. HODGES, 874 Broadway, N. Y 



SOFTLY STEALS THE LIGHT OF DAY 



when filtered through windows covered with 



CRYSTOGRAPHS, 



a substitute for Stained Glass that is inexpensive, 

 beautiful, and easily applied. 



20o. per square foot. Samples and catalogue, lOo. 



CRYSTOORAPH CO., 



316 North Broad St., PbUadelpbla. 



%kf. PARK i^AEKNEWxraRfe 



CS/VTiiQgR F^ H 



Sold by Druggists or Bent by mall, 

 BOc. E. T. Hazeltlne, Warren, Pa. 



,..^ ASK-USCi, 



^;IS9laS:Al:c:eSs'e 



BUILDiSG 

 BOOKS. 



DRAWING 

 INSTRUMENTS. 



1893 Catalogue 



of Books on Building, 

 Painting, and Decorating, 

 also Catalogue of Draw- 

 ing Instruments and Ma, 

 terials, sent free on appli- 

 cation to 



\rin. T, Comstock, 



23 Warren St., New York. 



^Every reader of *' Science " should sub- 

 scribe for the 



AMERICAN ARCHITECT, 



TSE OIDEST A'SD BEST 



Architectural publication in the country. 

 Interesting articles on architecture. Sani- 

 tation, Archaeology, Decoration, etc., by the 

 ablest writers. Bichly illustrated. Issued 

 weekly. Send stamp for specimen copy to 

 the publishers, 



Ticknor & Co., 211 Tremont St., Boston. 



THE AMERICAN MCE. 



By DANIEL G. BRINTON, M.D. 



"The book is one of unusual interest and value.'*-* 

 Inter Ocean. 



" Dr. Daniel 9. Brinton writes as the acknowledged 

 authority of the subject."— PAitadeipftia Press. 



" The work will be of genuine value to all who 

 wish to know the substance of what has been found 

 out about the indigenous Americans."— iVatwre. 



"A masterly discussion, and an example of the 

 successful education of the powers of observation." 

 —Philadelphia Ledger. 



Price, postpaid, $2. 



RESTORE YOUR EYESIQHT 



^Cataracts, scars or films can be absorbed and 

 paralyzed nerves restored, 'withoat the knife 

 or rrsk* Diseased eyes or lids can be cured by 

 GUP home treatment. "We prove it." Hun- 

 dreds convinced. Our illustrated pamphlet, . . ^, , , ..^-xi-..^- 



' Home Treatment for Eyes " free. Don'tmlssit. Q7ARROADWAY. NEW YORK. 



BveiyboOywantelt. " Tea iya," Glens Falls. N.Y. ^ '^ on^^^vv^ i , i^i-w i w 



N. D. C. HODGES, 



