80 



♦ KNOWLEDGE 



[Febkuary 1, 1887 



inside one, which was to be divided into 46 equal parts. 

 The number of .each of the subdivisions was marked against 

 its corresponding quadrant in the instrument. Now one 

 edge of the bar carrying the sight vanes passed, when pro- 

 duced, through the common centre of all the circles, 

 and Nonius supposed would cut some division on one 

 of the circles accurately ; then the angle corresponding to 

 this division is calculated from the number of the divisions 

 intercepted and the entire number in the quadrant of 

 which the coincidence occurs. Thus, suppose that the edge 

 were found to coincide with division 31 of the quadrant 

 divided into 72 parts, then the arc in degrees is |4 of 90° or 

 38° -15', and so with any other circle. This device, however, 

 never came into general use, for Tycho Brahe adopted it 

 only soon to abandon it for the diagonal scale (of his use of 

 which we have spoken before), and it comparatively soon 

 died a natural death. 



[To he continued.) 



THE NATURALIST'S LABORATORY. 



CONTRIBUTION VI. 

 Laboeatoby Furnitqre — (continued). 



HAIKS AND Tables.- — Simplicity of design 

 is here to be observed as a sine rpid nun. 

 The chairs used at the working table should 

 be armless, of the variety generally adopted 

 for bedrooms, or the so-called " Windsors " 

 of the kitchen ; but for comfort, elegance, 

 and portability the Bohemian bent-wood 

 chaire, with polished perforated wooden 

 seats, are to be preferred before cane-bottomed or solid 

 wooden seats. Upholstered furniture of any sort should not 

 be permitted to enter the room, as such articles not only 

 afford a clinging-place for dust and dirt, but are in themselves 

 small factories of those undesirable entities. A single armed 

 chair, however, of the kind known as the circular " oiSce- 

 chair," made entirely of French-polished ash or oak wood, 

 may be placed by the .side of an escritoire. 



Of tables, four patterns may be introduced with advan- 

 tage : — (t() The Dissecting Table — to be placed in proximity 

 to the sink and water-supply — ought to be made of well- 

 seasoned wood, and very tirmly built. The top of the table 

 should be about three feet above the floor, i.e. six or eight 

 inches higher than an ordinary writing table. This will 

 enable the anatomist to operate more freely whilst standing, 

 as it will be found that much of this kind of work can be 

 more efficiently and comfortably accompUshed in that 

 posture ; but provision should additionally be made to 

 enable the dissector to be seated, and a stool on the trivet 

 principle, without back or arms, will be found to meet his 

 wants most admiralily. 



The biologist's dissecting table shown at fig. 1 has been 

 devised to meet the requiiements of the naturalist's labora- 

 tory, private or public. It is intended as a working table 

 for one person, but, of course, by increased dimensions the 

 article may be modified so as to accommodate more than 

 one worker at a time. 



The black line / (fig. 1), over the top of the table, 

 represents a sheet of lead or zinc, guttered crosswise across 

 its surface, g. g. g., which cari-y blood, washings, ifec, into 

 basin B. A longitudinal gutter, which crosses the three 

 cutters above mentioned midway, is of course not shown in 

 the diagram ; t shows the table-top, affording a small border 

 of wood, two inches wide, around the metal. This device 

 allows for the attachment of dissecting hooks, connected 



to the subject by means of slender chains, whereby the 

 fascia, itc, may be turned and held aside to enable the 

 operator to work with greater ease upon any desired part. 

 The basin B can be made to discharge into a pipe leading to 

 a trapped sewer-gully, such as the famous " Kensington 

 trap " of Messrs. James Stiff & Co., of Lambeth, or its con- 

 tents may simply be received into a pail or bucket placed 

 immediately beneath the orifice of discharge under the 

 table, to be removed from time to time as occasion may 

 require. Whilst dissecting the student will find it advan- 

 tageous to keep the basin full of warm water, with a soft 

 sponge or two at hand, wherewith to sop up extraneous 

 humours ; a plug is therefore provided at the bottom of the 

 basin. One of the most important novelties, however, in 

 this table is the drawer, <7, which is fitted with a hinged 

 board, b, as shown in the figure ; when the drawer is pulled 

 out the board may be made to assume the position b', and 



Fig. 1.— Biologist's Dissecting Table. 



thus aflbrds an extempore desk, which can be inclined at any 

 angle to suit the convenience of the worker. It would be 

 well to have this board fitted with a superficial pad of 

 drawing-paper, upon which rough sketches, diagrams, and 

 notes can be readily made of the dissection from time to 

 time, and thus afford a lasting record of what may prove to 

 be of considerable importance when the student comes to 

 project a detailed description of his researches. The want 

 of this item is a source of great annoyance to the anatomist, 

 who often finds that his memory is apt to prove deceptive, 

 or that his notes on scraps of paper are insufficient or mis- 

 laid when wanted ; it does, in fact, supply that businesslike 

 methodicity which reaps its own reward, alike in science as 

 in commerce. When the drawer is closed, and the drawing- 

 board turned down within its recess, as shown at fig. 1, b, 

 it will be observed that ample space is left below it for 

 the storage of notes and drawings taken, and for a case or 

 two of dissecting instruments, d, boxes of pencils, ink, ifec. 

 A table thus constructed will be found most convenient for 

 amateurs, private laboratories, and such colleges as provide 

 separate benches for each student : it is a vast improvement 

 on those in common use either in this country or on the 

 Continent. The siu-face of the table-top should measure 

 about 3 feet 6 inches by 2 feet. The diameter of the basin 

 ought not to exceed 10 inches. 



(/3) The Microscopist's Working Table. — As a very lai-ge 

 part of the naturalist's work nowadays calls into use that 



