384 



SCIENCE. 



[Vol. V., No. 118. 



Experiments show that the progressive acceleration 

 of the rhythm brings about the modifications repre- 

 sented in the following table. The acceleration of 

 rhythm from sixty to eighty steps per minute has 



rsoo 







,1,11, y_J\J_ 





^4- 





1000 

 EDO 













a, 

 h 



1 2 3 >* 6 



7 a IB TV 12 13 Vt 15. 



Fig. 4. 



increased the length of the step, and decreased the 

 time required to travel a certain distance; but, when 

 we go above this, the opposite effect is produced. It 

 is better to replace the numerical table by the dia- 

 gram of fig. 5, which represents the variations in 

























Lt 



nguear 



da__ 













-»«.-^ 



65 70 



Fig. 5. 



85 90 pas 

 . Kla minute 



quickness of gait, and length of steps, as guided by 

 the electric bell ringing at different rates. 



Time of travelling over 



Number of double 



Length of double 



1,542 metres. 



steps to the 



minute. 



steps. 



20' 30" 



60 





1.35 m. 



18' 40" 



65 





1.37 m. 



16' 27" 



70 





1.45 m. 



14' 58" 



75 





1.51 m. 



13' 52" 



80 





1.50 m. 



13' 3" 



85 





1.49 m. 



14' 1" 



90 





1.32 m. 



NAVAL ARCHITECTURE IN ENGLAND. 



Francis Elgar, professor of naval architecture 

 at the University of Glasgow, devoted his inaugural 

 address, on entering upon his duties in November, 

 1884, to a history of the science. 



Until within comparatively few years but little at- 

 tention has been paid to the study of naval architec- 

 ture. Fifty years ago ninety-nine per cent of the 

 British merchant-ships were under five hundred tons, 

 and few measured more than a hundred and thirty 



feet. They were comparatively uniform; and, being 

 built after an established plan, they were perfectly 

 seaworthy when properly ballasted. In the case of 

 war-ships the matter was more difficult; as it was 

 necessary to get a type of ship which should be large, 

 high out of water, and able to carry many large guns, 

 without interfering with her sailing-qualities, or ren- 

 dering her top-heavy. 



In 1811 a school of naval architecture was started 

 in England, and during twenty years it trained forty 

 students. This was followed in 1848 by another 

 at Portsmouth, and in 1864 by a third at South 

 Kensington, which is now united with the Royal naval 

 college at Greenwich. Some excellent designers have 

 been graduated from these three schools. 



Before the use of iron, ship-building required no 

 elaborate calculations: it was simply a highly devel- 

 oped mechanical art. Ships were built of great rela- 

 tive depths in proportion to their breadth, and initial 

 stability was deliberately sacrificed to reduce the 

 tonnage measurement. Usually these ships would 

 not stand up, when fully rigged and light, without 

 ballast; and, judging from the proportions given to 

 them, they must also have required ballast when 

 laden with cargoes which were not composed of heavy 

 dead-weight. What is now required of the ship- 

 builder is to predict with great accuracy the weights 

 of complicated iron and steel structures, with all 

 their fittings and machinery; the weight of cargo 

 that such structures will carry at sea; the stability 

 they will possess in different conditions of loading, 

 and the treatment necessary to insure a safe amount 

 of stability being preserved upon all occasions; the 

 amount of steam-power and the rate of coal-consump- 

 tion required to maintain given speeds at sea; and 

 very frequently the strength that is possessed by the 

 hull to resist the straining-action of waves. 



The reason that the English schools for this study 

 have not been better attended, is that the courses are 

 too technical in character, and the requirements too 

 rigid, to attract any except advanced students. The 

 idea of the newly established chair of naval archi- 

 tecture in the University of Glasgow is to teach in a 

 less technical manner the new science, and to adapt 

 the course to the requirements of the students. The 

 policy will be first to fix what they already know, and 

 then to go forward to a complete study. Special stress 

 is to be laid upon long-continued and arduous prac- 

 tical training, combined with true science. The only 

 way in which superiority in ship-building can be at- 

 tained is by possessing a class of ship-builders who 

 have gone through just such a training, and who by 

 long study and work have acquired these theoretical 

 and practical principles. 



RECENT BRITISH LOCOMOTIVES. 



Engines recently designed for the London, Brigh- 

 ton, and south-coast railway of Great Britain by 

 Mr. Stroudley, were described by their designer at a 

 recent meeting of the British institution of civil en- 

 gineers. They were designed for freight-traffic, or as 



