February 1, 1887.] 



♦ KNONATLKDGE ♦ 



81 



most useful of niodern inventions, the compound micro- 

 scope, a special table designed to iacilitate research must 

 here be looked upon as something indispensalile. The 

 objects of the design, now submitted to the notice of 

 students of nature for the first time, are to afford general 

 convenience during study, and to enable one to record obser- 

 vations gnxphiciilly on the spot. To accomplish these the 

 table is divided into two parts — the microscopLst's, M 

 (fig. 2, A and b), and the artist's portion, d (fig. 2, A and 

 b). The dimensions of tlie table are clearly indicated 



Top View. 



Kir. l'. — MicRosconsT's Working Table. 

 A, Side Elevation. £, Top Plan. 



on the figures, a, tig. 2, is a working plan to show the end 

 elevation of the structure ; b gives a good idea of the shape 

 of the table-top. Each part is furnished with two drawers 

 as shown at a ; the drawers under d afiord space for the 

 storage of colour-boxes, pencils, paper, <fcc., those beneath m 

 are intended to receive microscopiail accessories, such as 

 glass slips, instruments, live Vioxes, troughs, and the 

 hundred-and-one odds and ends that may be required from 

 time to time by the worker in Nature's unseen universe. 



The longest end of the table, viz., tliat parallel with B, 

 fig. 2, B, ought to face ii window appro.ximately looking 

 northwards. The worker, seated on the bench t, fig. 2, b, 

 can thus employ direct or reflected light accoidiiig to the 

 ])osition, inclined, upright or horizontal, in which he places his 

 microscope. To his right there is fixed a i-eagent stand, r, 

 fig. 2, a and b. As soon as he has completed his oltserva- 

 tions, or adjusted an olyect which he deems worthy of 

 delineation, he should shift his instrument to the position d, 

 fig. 2, b, and take his .seat upon the chair s, fig. 2, b. By so 

 doing, he will gain the inestimable advantage of working in 

 a clear transmitted light without the chance of a vitiated 

 result through interference rays, and with absolute security 



against the evil efiects of a move or less intense glare. The 

 value of thus being able to shift one's position from front 

 to side on the table will soon become evident to workers 

 with the microscope who indulge in prolonged observations. 

 The top plan, tig. 2, b, shows the position of the microscope 

 during investigation, or whilst mounting objects ; B, place 

 for a dust-proof box, for use whilst i)repariug specimens for 

 observation, a detailed description of which will be given in 

 the sequel ; d, the po.sition of the microscope when used 

 with the camei-a lucida for delineating objects, or when 

 employed with the polariscope, or where pure transmitted 

 light is alone admissible; b, the reagent stand. 



(y) T/iK Occasional Table. — A round-topped table, pre- 

 ferably with a slate top, about 2 feet iu diameter, and iron 

 stand, is a very useful adjunct to the naturalist's laboratory. 

 Placed bv the window it affords a convenient place for 

 overhauling and sorting the captures of a day's pond-hunt 

 or country ramble, for untieing the life-habits of minute 

 organisms, and for general displays. Such tables may be 

 purchased from any dealer in microscopical ajiparatus, and 

 may be seen in full working order in the laboi-atory of the 

 well-known microscopi-st, Mr. Thomas Bolton, of Bir- 

 mingham. 



{&) T/ic Wrlt'uiij Table. — There can be no doubt that of 

 all forms the so-called library talile is the most useful here. 

 Its large Hat surface gives room for the artist to exercise his 

 ability in making large drawings or diagrams wherewith to 

 illustrate lectures or papers ; there is also plenty of space 

 for the current journals, in addition to elbow-room for the 

 author. Libr.iry tables may be purchased in all sizes, to 

 suit the dimensions of the student's apartment, from most 

 respectable furnitui'e dealers. 



In our next contribution we shall conclude this subject, 

 with detailed descriptions of various articles necessary to the 

 equipment of a perfect laboratory, inclusive of such apparatus 

 as do not strictly come under the heading of instruments 

 for i-esearch. 



THE WHIST SUPERSTITION DISPELLED.* 



By " Five of Clubs." 



anyone were asked how often he held a single- 

 ton he would probably answer, " In one hand 

 out of tirciUi/," or some such high number. The 

 real proportion is one in little more than three. 

 Anyone who cares to note as an evening at 

 whist proceeds, and evening after evening for a 

 considerable time, the number of singletons he 

 hold.s, or that others in the company hold, he will find that 

 this is about the proportion shown in the long run. 



The proof is not simple, because a singleton can appear in 

 many diflerent ways, and each requires a separate calcula- 

 tion. But those who posse.ss our little treatise, " How to 

 Play Whist," will find under the head " Whist \Vhittlings," 

 in pages 19-i to 197, the necessary details for the calcula- 

 tion ; or they may take the results ther(^ collected as already 

 calculated. The "table at p. 19G .shows the chance of every 

 possible arrangement of suits in a hand, from the most 

 frequent ca.se — 4 of each of two suits, o of a third, and 2 of 

 the fourth — to the case of 13 cards of one suit. The table 

 further shows, by the way, the chances for every possible 

 arrangement of the 13 cards of a suit in the four hands, 

 from the most frequent case — i cards of the suit falling iu 

 each of two hands, 3 in a third, and 2 in tho fourth — to the 

 case of all 13 cards falling into one hand. 



Now, collecting from this table at p. 196 of " How to Play 

 Whist" all possible arrangements of the suits in a hand by 



• See last number of Knowledgi:, p. 57. 



