

33 



and at right angles to it, a small flat piece of metal, e, of the form 

 of a trapezium, having in it a triangular hole, through which 

 a triangular bar, / g, works, which bar has at the extremity, g, a 

 flat piece also projecting at right angles from it, and in the opposite 

 direction to the piece, e. Through the piece, g, is drilled a circular 

 hole to carry a small cutting diamond, h ; at i and j are two screws 

 with milled heads, the former for holding the diamond firmly, and 

 allowing it to be adjusted to its best cutting edge, or to be removed ; 

 and the latter for holding firmly the triangular bar, /, after it is ad- 

 justed, so that the diamond point will be distant from the centre of 

 the cylinder, d, equal to the radius of the circle required to be de- 

 scribed. The triangular bar may have marked on it a scale for fixing 

 it to any requisite radius. Attached to the brass tube, b, is a wooden 

 disk, k. The tube is about half an inch shorter than the steel rod 

 which runs through it, and the former turns on the latter easily. 

 The lower end of the cylinder of wood, d, should be made quite flat, 

 and roughened by sand-paper. 



To use the instrument, take hold of it by the brass tube just above 

 the wooden disk, k; with the fore finger and thumb of the right hand, 

 place the end, d, on to the thin glass to be cut, and hold the ivory 

 handle, c, with the left hand, so that the rod is in a perpendicular 

 position ; allow the diamond point to come down upon the glass, and 

 cause the whole, with the exception of the steel rod, to revolve, 

 exerting a slight pressure on the disk, k, according to the thickness 

 of the glass to be cut. When the revolution is complete the disk will 

 readily separate. 



In collecting Infusoria, &c, for microscopical investigation, it is 

 often necessary to approach pools of water in very swampy localities, 

 as it is in such situations that the best specimens are most frequently ■ 

 met with; for this and for other reasons a long stick to hold the 

 bottle for procuring them is highly useful. 



I, in common with many others, have found an ordinary " walking- 

 stick fishing-rod," or rather, the two lower joints of it, very conve- 

 nient for the purpose. Various contrivances have been resorted to 

 for the purpose of attaching the bottle to the stick, and it is my 

 method of doing this, that I purpose describing. I should premise, 

 that the points I have aimed at achieving are, first, capability of 

 holding a bottle of any reasonable size, and secondly, capability of 

 being included within the stick, so that with stick alone, and a bottle 

 or two of any kind, that may be at hand, in the pocket, one would be 



TRANS. MIC. SOC. VOL. m. F 



