43 2 General Notes. [May, 



stuffs, etc. These lenses should all be of very high angle, unless 

 the expense be a positive objection. An instrument costing $50 

 to $75, would be sufficient for every-day use in a mill for examin- 

 ing the stock as received and worked up ; but one worth $300 is 

 none too good for a person designing to give advice and decisions 

 "as an expert in obscure cases. 



The editor of the Boston Journal of Commerce has introduced 

 the microscope into this field in this country, and has already in 

 important cases detected the cause of the imperfect working of 

 cotton apparently of good quality. He strongly endorses the 

 practical value of the use of the microscope by the cotton mill 

 agent or superintendent, specifying, among other things, that " it 

 tells him the effect of different mordants at a glance, the effect of 

 various chemicals which are used, also the real value of different 

 dye stuffs or drugs, and wherever the mixing of fibers is followed 

 or the actual fabric of goods is to be investigated, there is no 

 other possible way to do it than by the microscope." 



The prominence which the microscope "~ - 

 country in this techni< 

 fact that in the catalog 

 signers and others engaged in the manufacture of textile fabrics 

 by A. & A. F. Spitzli of West Troy, N. Y., of the 1 18 pages ot 

 the catalogue, the first 48 are devoted to microscopical apparatus. 

 Messrs. Spitzli also publish a " Manual for managers, designers 

 and weavers," an octavo book of 250 pages, which is of interest 

 to all. whether of scientific or of practical intent, who are de- 

 sirous of studying thoroughly the structure of fabrics. 



Practical Microscopy.— Under this title Mr. George E. 

 Davis, editor of the Northern Microscopist, has issued a general 

 text-book of the microscope and its manipulation. It is a work 

 of over 300 octavo pages, illustrated with wood cuts, and pub- 

 lished by David Bogue of London. The author announces his 

 intention, with a cheaper and more modern book, to occupy much 

 the same field as did Queckett's now obsolete treatise on the 

 - Use of the Microscope." He practically makes good the claim 

 to be a successor of Queckett by ignoring American and conti- 

 nental apparatus almost entirely, and confining himself to descrip- 

 tions of English work. Moderate credit is given, in the preface 

 and elsewhere, for American precedence in the introduction o 

 high angled objectives ; but these objectives (or any of America! 

 make for that matter) are omitted from the practical part ot tn 

 work. Only one American stand is described, arid the . ac Jf?" 

 sories mentioned are almost exclusively English. While tn 

 peculiarity may make the book more convenient for practical us. 

 among its largest constituency, nearer home, it will render 

 somewhat less attractive and satisfactorv to American students 



A similar deficiency occurs in the bibliography of alg«, £ 

 soria etc., of minerals, and mosses, where no mention is made ot 



