860 AncHysis of Scientific Books and Memoirs, 



called floats, which present so many cutting or file edges, against which the 

 knife is pressed when drawn backwards and forwards. 



Another patent has been taken out in May 1828 by Mr F. Westley, for 

 a similar apparatus, which is a decided copy of the principle of Mr Fel- 

 ton's invention, without being an improvement. It may, however, be 

 cheaper, and more easily made. It consists of four pairs of straight bars 

 of steel, with file edges, each pair being placed like a St Andrew's cross, 

 and at the same acute angle. The knife is then drawn between them as 

 in Mr Felton's contrivance. The inclination of the bars may be varied 

 with a screw. 



Another method of effecting the same purpose has been invented by Mr 

 Blake of SheflSeld. A series of file-edged bars are connected together by 

 an axle passing through their centres, so that they can be set at any angle, 

 and fastened by a screw. 



We have no doubt that a better contrivance than any of them would be 

 to use two ground surfaces of variable curvature, (parabolic, for example,) 

 so that various inclinations of the cutting surfaces could be obtained by 

 merely making the one revolve round upon the other. 



8. Description of the Pneumatic Spoon. Invented by Mr Gibson. 

 This truly ingenious and useful invention has been very properly re- 

 warded by the Society of Arts with the Isis Medal. It is shown in Plate 

 II.Fig. 11, and has a lid L, opening round the joint, a b. Its handle H is a 

 tube, the extremity of which E, is a circular disc, upon which the opera- 

 tor puts his thumb. The fluid is introduced at the lid L ; and when the 

 lid L is shut, and the thumb placed upon E, the spoon may be held in any 

 position, without the fluid falling out. Hence it is especially valuable in 

 administering food or medicine when the patient is in bed. When the 

 spoon is inserted in the mouth, the food or medicine falls out of the spoon 

 by withdrawing the thumb from E. 



Art. XXVII.— ANALYSIS OF SCIENTIFIC BOOKS AND ME- 

 MOIRS. 



TTie Natural History of several New, Popular, and Diverting Living 

 Objects for the Microscope, with the phenomena presented by them under 

 observation^ 8^c. &;c. Conjoined with accurate Descriptions of the latest 

 improvements in the Diamond, Sapphire, Aplanatic, and Amician Micro-' 

 scopes ; and instructions for managing them, S^c. 6;c. To which is added 

 a Tract on the newly discovered Test Objects. Illustrated by very high' 

 ly finished Coloured Engravings, from drawings of the actual Living Sub- 

 jects. By C. R. Goring, M. D. and Andrew Pritchard. No. I. 

 Lond. Feb. 1829. Pp. 32. 2 8vo. Coloured Plates. 

 Iji a preceding article of this number (p. 327) we have already had oc- 

 sion to give an account of the labours of Dr Goring and Mr Pritchard re- 

 lative to the improvement of the microscope. Impressed as we are with the 

 high importance of this branch of science, and with the great value of the 

 improvements which these geiitltraen have introduced, we naturally looked 



