Oct. 13, 1882. 



♦ KNOWLEDGE ♦ 



333 



please let me know. — A. A. Murdoch. No room for Dranfjhta 

 or Billiards, though nndoubtedly, like Whist and Chess, scientific 

 games. — H. M. Thanks, but no space for your story. It shows 

 that trout clearly recognise the difference between " the free and the 

 constrained motion of a rigid body ; " yet, I dare say not one of 

 them has studied Routh's " Rigid Dynamics."— A. McD. Mr. W. M. 

 Williams's theory is not open to the objections you make. Ac- 

 cording to it, as he e-tplains it in his " Fuel of the Sun," our oceans 

 could not bo diminished by evaporation, for he supposes inter- 

 planetary space to be " saturated " — that is, whatever amount of 

 aqueons vapour would saturate the interplanetary atmosphere at 

 any point, at the temperature and pressure there existing, is actually 

 present. This answers the first three questions. As to the fourth, 

 it is impossible to say what the weight of the vapour of water is, 

 unless you s.ay where, and under what conditions, it exists at the 

 moment. 



Letters Recefved. — J. Munroe, F. Gardener, J. Searson, F. W. 

 Richardson, Hallyards, J. M. L., Young Chemist, F. C, Wood, 

 Opifer, B. Lingwood, Taranaki, W. H., Bansall, Newton Crosland, 

 S. Spicers, Dentist, H. B. Richardson, G. Griffith, H. G. White, 

 W. P., E. Brown, H. A., T. A., Surgeon, J. B., F. W. Lambley, 

 F. R. M., J. Greenfield, A. W. Soward, I. Probert, Vega, A. G. 

 Haynes, Matriculating Student, J. Fraser, Malcolm Douglas, Sub- 

 scriber, E. Irving, J. H. Ward, Odontalgia, Excelsior, G. Massie, 

 C. Cams-Wilson, E. T. C. W., A. Leluem, J. T. B., T. N. A., M. E. L., 

 C. Witham, J. E. S., C. S., L. Dobbin, Naus Solannm, E. D. G., J. 

 Spiller, Grateful, C. E. S., W. B. Wicken, H. H. Newton, C. H. 

 Romanes, Ignoramus, F. Keith, D. lUingworth, A Highlander, 

 J. P. K., Upsala, G. R. W., M. B. A. 



^ir iHatDfmati'cal Column. 



To determine the time in u-hich a bodij leaving the sun's surface 

 t-ertically, xcith a velocity of 3S0 miles pe'r second— bdng that u-ilh 

 which a body travelling to the sun's surface from rest at an indefi- 

 nitely great distance would reach that surface under the influence of 

 his attractive force—it is required to determine how long that body 

 ivould be in reaching a distance of thirty millions of miles from the 

 centre of the sun. 



O R p q P 



Lot O be the snn's centre, R the point on his surface from which 

 the body is projected; OR = 430,000 miles, OP -30,000,000; but 

 put OR = r, OP = a. Also let OP = x, pq = d.r, and velocity at 

 R = f. Then we know that the velocity of the body varies in- 

 versely as the square root of the distance from O. Hence velocity 



at p = u /_^ jjjj^ jjjjjg ^f traversing P9 = -v/ — dx. Hence 

 time of traversing the distance RP 



■iWT-'l 



„ 3u 1110 /a> /270 



"^ 2 2~^^''^' ""'' V "7 = V "^ • 100000000, the mile 



being the unit of length and the unit of time. 



Whence the quantity within square brackets =250,000,000 nearly 

 enough. And the time required 



25,000,000 

 = — - '— seconds 



57 X 3600 X 2i ' 



4925 



This is also very nearly the time in which a comet, moving in 

 exceedingly eccentric orbit, >vith perihelion close to snn, wonld take 

 in reaching the same distance from his centre. 



CiCTlox.— Beware of (he Party offering imilations of the ■■ Bi(t W»T«Tley" 

 and Big " J •' Prn. Sold by all re«pect«hle Stalionern throughout the world. 

 " Thev pome a« s boon and a 1>Io§t>)nf; to men, 

 Thi. Pi.-l-iriok. the Owl. and the Waverlev Pen." 

 Al«o the niniioo IVnu. Diagonal Points, No«. 1, 3. and 3. .''ample Boi with all 

 the kind-. N. Id hy post. Patentee* of pens and penholder*. Afacnircn ,^ 

 Cameron. Pen-maker* to her Majesty's Qoteninient. OOlces. S3, Blair-street. 

 Edinburgh. (Established 1770 



<Bnr aaafti'st Column. 



By " Five of Clubs." 



THE evenings are closing in again, and Wliist begins to resume 

 its place in the day's recreations. We propose, therefore, to 

 continue our discussion of the principles of Whist play, with occa- 

 sional illustrative games, problems. Whist gossip, and so forth. 



But as some of our readers may have forgotten what we have 

 already written, we propose to give a very brief summary of the 

 chief rules, — those rules which every Whist-player oaght to have 

 constantly in his memory, the breach of them being, in fact. Whist 

 atrocities. For details the reader can consult our former papers. 



The Lead (from strength in plain suits), 

 See preceding numbers, especicdly No. 14. 

 Lead Ace — 



(1.) From Ace and four others at least, following with small 

 one ; or (2) from Ace, Queen, Knave, with or without others, 

 following with Queen if there were not more than four in the 

 suit originally, otherwise with Knave. 

 Lead A'tn^ — 



(1) From Ace, King, and others ; following with King. 

 (2) From King, Queen, and others; following with small one it 

 ■King makes. 

 Lead Queen — 

 From Queen, Knave, Ten ; following with Knave, if Queen 

 makes, unless you were more than four in suit originally, when 

 follow with lowest of head sequence. 

 Lead Knave — 



(1) From King, Queen, Knave, two others or more. (2) From 

 Knave, Ten, Nine, ^vith or without small ones. Sequent play 

 will depend on the fall of cards in the first round. The trick will 

 not probably fall to leader in either case, as either adversary or 

 partner, holding Ace, would generally play it. 

 Lead Ten— 



(1) From King, Queen, Knave, Ten, and (2) from King, Knave, 

 Ten, with or without others. 

 Lead Nine— 



From King, Knave, Ten, Nine. 

 In other cases lead lowest if you have only four cards ; lowest 

 but one (the penultimate) if you have five or more; some play 

 lowest but two (the ante-penultimate) when holding six or more. 

 The LE.\n in Tbvmps (from strength). 

 Note the trump card, and only lead np to an honour turned on 

 your right when very strong. Do not hesitate to do so, however, 

 when you have strength in trumps, and either you or your partner 

 has a good suit. Play a waiting game in trumps, your object being 

 rather to get the command than to win the earlier rounds. From 

 King, Queen, and small ones, it is generally better to lead the 

 lowest. 



LE.tDrXG PROM A WEAK SUIT. 



From Ace, King, or Queen, with two small ones, it is best to 

 lead the lowest, unless you have reason to believe your jwrtner has 

 strength in the suit. (Some, however, from Queen two small 

 ones, load Queen.) In other cases, when obliged to lead from a 

 three-card suit, lead the highest. From two cards, if driven to 

 such a lead, invariably lead the highest. 



N.B. — Note the inferences from these rules. Your own hand 

 will often serve to tell you precisely what the lead moans. Thus, 

 supi)Ose Ace is led and you hold King, Knave, — you tnon know the 

 lead is from Ace fonr others. Again, Knave is led by your partner first 

 round, and you hold King, Ton; you know that the lend is not from 

 strength (see leads from strength above) ; hence, that your partner 

 holds four trumps, and three three-card suits, all weak, the best 

 being headed by the Knavo played. So in multitudes of other 

 cases. 



Play Second Ha.nd. 



With King, Queen, ono other, or Quron, Knave, one other, or 

 Knavo, Ten, ono other, or Ten, Nino, ono other, play lowest of head 

 sequence ; but with same heod sequence and two others or more, 

 play lowest. With King, ono other, or Queon. one other, in plain 

 suits play the lowest, unless you specially want the load. 



Of course, tliero are other Vnlos for play second in hand, see Part 

 21 and several preceding parts ; but these are the most clomentary 

 rtiles-though often neglected. 



In our next we shall summarise the rnles for ploy third and fourth 

 hand, and repeat some of those general rules which form the 

 elementary language of the game. We shall then resume our more 

 complete analysis of Whist principles. 



