446 



KNO^A/'LEDGE 



[March 24, 1882. 



><ilour8 ln'iiiK so wi'll contrasted, 'i' is a triple star, but, 

 witli our o[)tii-ul iiii'aiis, will only bo scon as a mtlicr wide 

 iloublo. a Cn.ssiojii'iii', to tlu' south of li, is a beautiful, 

 (Iclii-fttf, and by no means ru-sy, double star; a sort of 

 miniature of i liootis, which wo shall dcsoribc in a future 

 " Nifjht," About K, between y and k, between n and n, ic. 

 Hi- some of the beautiful fields of stars to which reference 

 has been mndi' above. 



Cnmelopardus contains several more or less striking 

 pairs ; but as none of them are marked in our map of 

 reference, we pass on to Lynx, where wo lind 38 (Map, 

 ]). 20S) a very close, delicate, and rather diliicult pair. 

 10 l.yncisis a pretty triple, but it does not ajipear on the 

 map. As both Cepheus and Draco are below the Pole, we 

 must defer our description of the principal objects of 

 interest tliey contain until some future occasion. 



EiiiiATA. — In '• Nights with a Three-inch Telescope," on 

 p. 3"C, paragraph 2, lino 4, "lower circle" should be 



iiour circle ; and at the beginning of paragraph .3, 

 appears instead of Cancer. 



• Cancri 



NOTES ON ROWING. 



By an Old Clib Captaix. 



CONSIDER now in what respects the racing-boat of 

 our time difl'ers from the racing-boat of 1840. It is 

 much lighter, it is much narrower and sharper, and has a 

 perfectly smooth keel, .so that it encounters a much smaller 

 resistance, the leverage of the oar is greater, and the oar 

 is longer. Taking the last point lirst, we see that the 

 oarsman must pull the oar more sharply to give even the 

 same velocity of propulsion as in the old boats, for the 

 simple reason that he works at the end of a longer arm, 

 while the increased length of the other part of the lever 

 (the oar from blade to rowlock) only makes up for this 

 increase in the length of the part which lies between the 

 rowlock and the handle. It can readily be shown that, 

 apart from the actjuired motion of the boat, the driving 

 distance for one full sti'oke of the oar would differ 

 very little with the longer oars but increased lever- 

 age of our time from that obtained with the old 

 style of oars, if the angle through which the oar is 

 swept were the same as of yore. But to obtain this 

 angular sweep the handle of the oar of our time 

 must be carried through a distance, greater in just the 

 same degree that the distance from handle to rowlock 

 has been increased. The hands must, therefore, move 

 more quickly to give the same rate of pro}iulsion as to the 

 older boats. But these boats will take and retain between 

 the strokes a greater rate. Consequently the oar must be 

 urged more sharply still, if it is to be ell'ective in giving to 

 them the greatest speed they can attain. The long, steady 

 pull proper in the old racing-boats would give, no doubt, 

 to these much lighter boats the same rate of speed that it 

 gave to the heavier boats, and with much less effort to the 

 oarsman. But tlie racing-boat would not then travel at 

 the best pace that can be gi\en to it. 



I would call special attention here to the circumstance 

 that it is not a mere matter of opinion, but of absolute 

 certainty, that the same stroke which was good for the 

 old-fashioned racing boat must be ineffective for the 

 modern, outrigged, smooth-ljottomed, light racing craft. It 

 can even be shown that the actual stroke rowed by Selwyn 

 and his contemporaries, would not do more than simply 



follow the motion of a racing craft at full speed, instead of 

 adding to its velocity. 



L<'t us run through a little calculation, the elements of 

 which, l>e it noticed, are not open to doubt or question : — 



The University boats go over the 4^ miles course on a 

 good tide in alx>ut '1\ minutes. We shall not be far 

 wrimg in saying that a very good racing l>oat would cover 

 4 miles on still xisile.r in afjout 20 minutes, or would move 

 at the rat<' of 1 mile in .5 minutes (note that whether » 

 boat is travelling with or against the stream the rower 

 works as if in still water, for the boat shares the motion of 

 the stream). Certainly this speed is attained in spurts, 

 and a still higher speed in sharp bursts over a short cour'-' . 

 A mile in •") minutes, means ■■)-">2 yards per minute, or .3^7 

 yards (or 17'G feet) per second. This speed is not abso 

 hitely constant even in the lightest and best of our racing 

 boats ; but as e%ery one knows who has watched the pro- 

 gress of a bumping race when the pursuing l>oat has its 

 nose very near to or o\crlapping the stern of the pursued, 

 falls off perceptibly between the strokes. Still the falling- 

 off is very much less than in the best boats of half-a-century 

 ago. We may fairly take 19 feet per second as the 

 maximum velocity attained just at the end of stroke, and 

 16 feet per second as the minimum velocity just before the 

 beginning of the ne.xt .stroke. 



Now, 40 strokes to the minute is pretty nearly the 

 maximum attained even in spurts, the tendency being (as I 

 shall presently explain; to diminish rather than to increase 

 the numljer of strokes per minute. At any rate, 40 strokes 

 per minute is very quick rowing indeed. If, then, tlie boat 

 travels 1 7 '6 feet per minute, she covers about half as much 

 again per stroke, or 26-.") feet. In other words, a boat 

 travels very nearly nine yards at each stroke, in the case of 

 an absolutely first-class and perfi>ctly trained " eight " in a 

 good craft, rowing at top speed. 



Now, it requires, with an oar suited for an outrigged 

 craft, a very good reach forward and a good puU home, to 

 give the blade a sweep of six yards in the water ; and, 

 taking account of slip through the water and of the arc 

 nature of the blade's motion, we may consider five yards 

 an unusually good rffective sweep. Now, with the old- 

 fashioned stroke, the oar was in the water at least twice 

 as long as in the air, din-ing each complete stroke (from 

 feather to feather). If, then, this stroke were rowed now, 

 the oar would be two-thirds of the fortieth part of a 

 minute in the water, during which time the boat, with tlie 

 motion already considered (whether supposed to be com- 

 municated by previous effective strokes or by the rest of 

 the crew rowing properly), would travel six yards ; so that 

 rowing the old fashioned stroke in the old-fashioned way, 

 an oarsman would not be driving the boat at all, but 

 simply following with the blade of his 0£ir the (relative) 

 motion of the past rushing water. 



It is obvious, then, that the stroke which was so 

 effective in 1840 will not do now. It is equally certain 

 that the requisite rapidity of propidsion caiuiot be attained 

 by rowing the same sort of stroke, but more to the 

 mimito ; for experience sliows that no crew can keep up 

 so quick a stroke as would be required — rowing full length, 

 be it noticed, for else the quickening would do no good. 

 Nor can men take a much longer stroke (in the same 

 time), e\en with tlie modern sliding seats. Leverage is 

 lost with increase of length : and though up to a cer- 

 tain point this consid(>ration must be overlooked, it 

 tells very much when the question is of adding a 

 foot or so of forwai'd reach to the reach which had 

 already l>rought the oar to an inclination of some 40 

 degrees to the mid position when the levei-age is greatest 

 The sliding seats add something to the old length of stroke. 



