1 882.] Microscopy. 431 



Fig. 1, the compressorium is long and narrow and fitted with a 

 pair of 3 x 1 glass slips, such as are commonly used by micro- 

 scopists, and it is supplied with a magnifying doublet of sufficient 

 power for the easy recognition of trichinae. Instead of the 

 doublet, or compound microscope tube may be used, in which 

 case it is best combined with a short compressorium having 

 round disks of thin glass as shown in Fig. 2. On the whole, the 

 simplest form, as drawn in Fig. 1, is considered preferable, and it 

 is furnished at the remarkably low price of $3. Aside from its 

 intended use, this instrument is an excellent pocket microscope 

 for field use when making collections of algae and infusoria among 

 the ponds and ditches. 



Structure of the Cotton Fiber.— Foremost among the in- 

 stances of the present day, of the application of scientific methods 

 and instruments to the development of economical interests, is the 

 microscopical study of fibers and fabrics. The three lectures on 

 the structure of the cotton fiber, delivered by Dr. F. H. Bowman 

 before the Bradford Technical School in 1880, have been pub- 

 lished in Manchester, and they constitute a volume of remarkable 

 interest and value. 1 



Dr. Bowman combines, in a rare degree, the love of truth and 

 the analytical methods of a scientist with the practical sense of a 

 business man, and his book, though intended primarily for the in- 

 struction of cotton spinners and others concerned in that industry, 

 is a still greater acquisition to the library of the botanist and the 

 microscopist. The development, size, structure, and varieties of 

 the different kinds of cotton fibers known to trade, their varieties 

 of place and season, their qualities and faults, and their behavior 

 under the processes of preparation, dyeing and spinning, are dis- 

 cussed with great thoroughness, and are illustrated with good 

 drawings. A companion book on the structure of wool is 

 promised by the same author. Thus is opened by science a field, 

 whose importance has scarcely been realized before, for the prac- 

 tical improvement of those engaged in the manufacture of fabrics. 

 The author's incidental directions for the microscopical examina- 

 tions upon which the whole work is founded, are in the main 

 judicious and excellent, and we fully concur in his assumption 

 that the best attainable objectives are desirable for the work ; 

 though the experience of the present day is rather in favor of the 

 employment, for such work, of smaller and simpler stands instead 

 of those as large and elaborate as the one figured by him. The 

 author does not specify the powers most available ; but we have 

 found a 1 inch or 1% convenient for preliminary survey of the 

 material, or -^ for the study of its general character, and a ^ or 

 * immersion for study of sections, local details, effects of dye 



1 The Structure of the cotton fiber in its relation to Technical Applications. By F. 

 «• Bowman, D. Sc 8vo, pp. 2 1 1 , pi.Ue, 1 1 J • m Wiley & Sons, 15 Astor Place, 



