ENGINEERING. 



286 



' I'Yain " was loaded to excess when she sailed 

 from Christ iiiiiin, every available foot of space 

 I'riiiLT necessarily packed with the stores required 

 for her long absence from iiny possible base of 

 .supplies. Seven large boats arc earned, includ- 

 ing a naphtha launch, and there is an abundant 

 supply of sledges and " Ski," or Norwegian snow- 

 shoes, such as proved so highly ellicieiil in the 

 I'eary e\|iedit ion. 



Tlie Ferris Wheel. Paris, in 1889, saw the 



loftiest structure e\er reared by mortal hands 

 the KilM tower -which still remains a monu- 

 ment of lightness and strength (see "Annual 

 Cyclopaedia " for 1888). Chicago, in turn, might 

 have built a still loftier tower, but she wisely 

 decided in favor of originality, and the largest 

 piece of mechanism in 

 existence was the result. 

 The general plan of the 

 wheel is evident from 

 the illustration. Its di- 

 ameter was 250 feet ; cir- 

 cumference, 825 feet : 

 width, 30 feet. The axle 

 was of steel, 32 inches 

 in diameter and 45 feet 

 long. Its ends rested 

 upon two skeleton iron 

 towers of pyramidal de- 

 sign, properly supported 

 upon concrete founda- 

 tions. The two wheels 

 that in combination 

 formed the great revolv- 

 ing structure depended 

 for strength upon the 

 familiar bicycle - wheel 

 principle, iron rods 2 

 inches in diameter being 

 substituted for wires. 

 But this spoke-rod sys- 

 tem reached only to an 

 inner crown, or tire, 40 

 feet within the extreme 

 periphery. The outer- 

 most tire consisted of a 

 curved hollow iron beam 

 25i x 19 inches. The 

 outer and inner tires 

 were held together by 

 truss - work, and the 2 

 twin wheels were united 

 by similar connections. 

 Each wheel had a huge 

 iron hub to which the 

 adjustable spoke rods 

 were made fast. The 

 carriages, 36 in number, 

 with a seating capacity 

 for 40 passengers each, 

 were hung at regular in- 

 tervals to the outer tire. The total weight of 

 the wheel with its full complement of passengers 

 was 1,200 tons ; and the fact that it did the work 

 expected of it without a hint of failure certifies 

 to the accuracy with which all the structural cal- 

 culations must have been made. The driving 

 po\\cr was applied through sprocket wheels and 

 driving chains to cogs on the outer tires, and a 

 system of clutch brakes kept the whole machine 

 under perfect control. To George \V. (.). Ferris, 



of Pittsburg, Pa., is due the credit of the : 

 .Mr. L. V. liiee superintended the construction. 

 It is imdcrr-tood that the wheel i> defined t,, find 

 a permanent home in New York. 



Tid i Indicator. In July there was erected 

 on the (iovernmcnt wharf at Kort Hamilton, 

 New York harbor, a tide indicator of novel con- 

 struction, as shown in the engraving. The disk is 

 ^o feet in diameter, and the index numerals are 

 large enough to be read with the naked eye at a 

 distance of a mile or two. The indicator is in 

 8 sections : 1. The scale, indicating mean low 

 water, and the other numerals marking feet. 2. 

 The pointer, which sweeps back and forth in the 

 semicircular space immediately below the scale. 

 3. The arrowhead, which, by pointing up or 



TIDE INDICATOR. 



down, tells whether the tide is rising or falling. 

 There are many tide indicators in use. but t lies- 

 are mainly for scientific observers. This is for 

 mariners, showing at a glance from a distance 

 just what every skipper wants to know. The 

 mechanism is simple, an adaptation of float and 

 counterpoise attached to a wheel that ojierates 

 t he pointer. The device deserving especial men- 

 tion is the arrowhead, which is reversed by the 

 tilting of its barbs, pivoted at their inner angles. 



