292 



• KNOWLEDGE . 



[Oct. 10, 1884. 



or the horizontal i-esolved part of the missile's velocity 

 westwards is equal to the velocity of the point of projection 

 eastwards on account of the earth's rotation. In this case, 

 and in this case only, the range of the missile is the same 

 (apart from atmospheric resistance) as that given by the 

 usual formula. 



In order that a missile should fall exactly at the point 

 of projttction, we must have, manifestly, the northerly 

 range (estimated by the usual formula) equal to the 

 southerly displacement, and the easterly range equal to the 

 westerly displacement, giving the equations 



8 

 2<iv cos £ sin a = — tjiv cos t sin a (L) 



3r 



Q 



and iliV cos e cos a = — tihOv cos e cos a + u) (il) 



3r 



(i.) is satisfied if £ = 90°, or if a = 0°; or if /t=-r 



4 



3r 



(ii.) cannot be satisfied if t = 90° or if h = 



■i 



(ii.) is satisfied if 



3r . V cos J =4/4(1; cos £+?«); 

 which may be written in either of the forms 

 ihu 



If a = 0. 



(iiL) 



V cos £ = 



and 



h = 



Sr- 4/t 



Srv cos £ 



(iv.) 

 (V.) 



4(i) cos £ + m) 



(iv.) Shows what the horizontal velocity (east) should be 

 it the missile is projected to a given height, /( ; and (v.) 

 shows what the height should be if the missile has a given 

 horizontal velocity (east) ; in order that a projectile should 

 fall back to the place of projection. 



In all cases of actual missiles or projectiles, h is very 

 small compared with r, the earth's radius, and v cos £ is 

 very small, compared with u ; so that — 



(iv.) may be written i^ cos £=— ^=-l/t cos \ (vi) 



3?- 3P ^ ' 



and (v.) may be written 7i= 



3ry cos f 3P v cos £ 



4ti Ss- cos \ 



which is the same as equation (vi.). 



To illustrate the application of (vi.) ; suppose /t=l,000ft., 

 and X = 0, or the point of projection is on the equator. 

 Then v cos t, or the resolved part of the velocity of pro- 

 jection parallel to the horizons 8000x3-1416 /„gj^„ 



3x24x60x60^ " 

 ordinary instead of a sidereal day), 



_251j328_2.51-32S 

 108x24 2592 

 or the horizontally resolved part of the velocity of projec- 

 tion is less than the 10th of a foot per second. The 

 velocity of projection may be regarded as identical with 

 the vertical velocity, giving 



i;2=2^A = 32200 

 or X =180 ft. per second very nearly. 



Hence the angle of projection is so nearly vertical that the 

 vertical part of the velocity exceeds the horizontal more 

 than 1856 times. The inclination to the vertical would be 

 almost exactly 1' 50", or £=89° 58' 10". 



TiiE Ht. Petersburg Berald reports that Capt.iin Kosztowitz is 

 building at Okhta a large cigar-shaped balloon, 200 ft. in length and 

 80 ft. in height, including the car, which he has furnished with a 

 screw and also with wings. He considers that he will be able to 

 take a crew of sixteen men and 250 lb. of ballast, at the rate of 

 forty German miles an hour, and the experimental trip is expected 

 to take place early next month. 



EMIGRANTS' PROSPECTS IN 

 CANADA. 



FROJI AX ENGIXEEE'S POINT OF VIEW. 

 By W. R. Browne, M.A. 



{Continued from page 237.) 



IF Canada offers no field for English engineering, it does 

 not follow that it oflTers no field for English engineers. 

 The rapid development of the country, agricultural and 

 otherwise, cannot but create a demand for manufacturing 

 and repairing shops, and therefore produce favourable 

 openings for capital in those directions. But capital is 

 scarce in Canada, and what there is goes, most naturally, 

 into the two great staples — land or timber. There are 

 hundreds of young men now in England with a good 

 engineering training, industrious habit«, and a small capital 

 to fall back upon, who yet find it almost impossible to get 

 any suitable opening in Great Britain. Such a man might 

 do worse than betake himself to Canada, and content him- 

 self for a year or two with earning journeyman's wages — 

 say, 8s. a day — in some good country shop, keeping in view 

 the hope of becoming a partner, in that or some similar 

 concern, as opportunity offered. A sketch of one such 

 country machine works, to which I paid a brief visit, will 

 show the nature of the prospect thus offered. The works 

 in question are situated at Sherbrooke, one of the most 

 thriving and prosperous towns in what are called the 

 " eastern township.s " of the province of Quebec. In great 

 measure it owes its prosperity to the fact that the River 

 Magog, after passing through a succession of lakes, acting 

 as natural reservoirs, here falls into the St. Francis in a 

 succession of picturesque cataracts, having a total height 

 of about 200 ft. It is only a small section of the fall with 

 which we are concerned at the moment ; yet this is 

 sufficient to give, day and night, summer and wint«r, a 

 continuous supply of not less than 700-horse power, which 

 is utilised by an arrangement of high-speed turbines for the 

 needs of a large three-storied building. One part of this 

 building is occupied by the machine works now to be 

 described ; another by a mill for rasping up soft wood and 

 converting it, by the addition of water, into a sort of fine 

 gruel, which is afterwards pressed between rollers and 

 turned into paper pulp. Yet a third part is occupied by a 

 number of light tools for turning out bobbins of all shapes 

 and sizes ; and a fourth by the shops of a general joiner 

 and undertaker. To return to the engineering works. 

 They were founded about thirty years ago by an artisan 

 from the United States, the present proprietor, whom I 

 found working steadily at his vice among his hands, Hke 

 an English millwright of the olden time. His son, who 

 acts as outdoor manager and general foreman, took us 

 round, and was ready to answer any questions. The fitting 

 shop was occupied with a variety of machines, entirely of 

 American or Canadian construction, but not wanting in 

 solidity or excellence of finish. This was specially 

 noticeable in a shaping-machine by Mackenzie and 

 Bertram, of Dundee. Modern improvements were not 

 wanting. For instance, a lathe, by the Putman Manu- 

 facturing Company, had an emery wheel mounted 

 alongside the bed, which was traversing along it and 

 rapidly polishing a roll for a paper-mill. A good deal 

 of work is done in repairs for paper-miUs, which form a 

 considerable industry in this neighbourhood, and also in 

 the repairs and erection of saw-mills and other wood- 

 working plant. In addition, the firm contract— at day 

 rates — ^to do all the repairs for two lines of railroad in the 

 district. These are among the many new roads brought 



