648 Zoological Journal. 



judges, and subsequently available to the views of the gene- 

 ralising compiler and systematist. It surely can scarcely be 

 doubted that the public is now enough imbued with a regard 

 for natural science, to patronise a work of this scope suffi- 

 ciently to cause it to remunerate those who may embark in it. 

 During the latter portion of the life of Mr. Carpenter, Gill's 

 Technological Repository was frequently enriched with the 

 very interesting results of his microscopical investigations; 

 but a work appropriated solely to the reception and diffusion 

 of this kind of knowledge would, we apprehend, be received 

 by the scientific public with increased welcome. 



To return to the Microscopic Cabinet, As above implied, 

 the remaining pages and plates discuss the more strictly 

 optical considerations which appertain to microscopes and 

 engiscopes ; this latter term being used to express those in- 

 struments " which exhibit an image of the object, whether 

 they be reflectors or refractors." Of this part of the work, 

 we declare ourselves incompetent to judge, but may say, it 

 seems abounding in highly scientific and practical knowledge, 

 which will probably considerably, perhaps vastly, avail the 

 users and studiers of microscopes. After remarks on the 

 requisite qualities of perfect instruments, and on the author's 

 mode and materials of structure to produce these qualities, 

 two plates and several pages of remarks are supplied on " test 

 objects ; " among which we are again treated, although inci- 

 dentally, with information on insects. Insects, however, are 

 not the only "tests" introduced; for, as "new test objects," 

 there are presented " engravings of the appearances presented 

 by magnified artificial stars (globules of quicksilver on a black 

 ground), and white rings or annulets painted on a black 

 enamel plate, or dial, when viewed within and without the 

 focus of microscopes and engiscopes of different qualities." 

 The vegetable kingdom seems to have been so slighted, that 

 scarcely any " test objects " have been chosen from it ; but it 

 may be that they are inapplicable as " test objects," although 

 objects of very high interest for ordinary microscopical in- 

 spection. 



Vigors, N. A., F.R.S., Editor: The Zoological Journal, 

 No. 19. Price IO5. ; or, with the Plates uncoloured, 

 7s. 6d. Part IV. of Supplementary Plates, price I8s.; or, 

 with all the Plates uncoloured, IO5. : the Coloured Copies 

 to Members of the Royal, Linnaean, Geological, and 

 Zoological Societies, 153. 



Both the above were published in July last. The number, 

 on its cover, is stated to occupy the interval from July, 1830, 



