474 KANSAS CITY REVIEW OF SCIENCE. 
large amount of piling, false or temporary supports, etc. Masonry in the six 
piers, twenty-seven hundred yards; in abutments and trestle work, eleven hun- 
dred yards. ‘Total, thirty-eight hundred cubic yards. Béton work, six hundred 
and fifty cubic yards. 
The entire structure was designed by Chief Engineer George S. Morrison 
and executed under his direction, assisted by First Ass’t Engineer, H. W. Park- 
hurst and Ass’t Engineers, C. C. Schneider, B. L. Crosby and W. G. Dilworth. 
The two four hundred foot bridge spans were manufactured and erected by the 
Keystone Bridge Company of Pittsburg, Pa. 
The entire cost of the whole structure when completed, will be under seven 
hundred thousand dollars. 
On August 30th, 1880, the strength of the bridge was tested by running on 
each of the two four hundred foot spans alternately, and over the entire structure 
eight locomotives loaded with coal and water, and concentrating a total weight 
on each bridge span of about four hundred and fifty tons, under which a deflec- 
tion of three inches only was produced. 
For the foregoing description I am largely indebted to Messrs. Geo. S. Mor- 
sison and H. W. Parkhurst, Chief and Ass’t Engineers on the bridge, and to ar- 
ticles published by them in the ‘‘ Angéneering News,” from which I have freely 
quoted. 
RAILROAD BUILDING IN THE ROCKY MOUNTAINS. 
The Denver & Rio Grande Company is at present engaged in constructing ex- 
tensions in seven directions: from Alamosa to Silverton ; from San Antonio to Santa 
Cruz, New Mexico; from Cafion City to Silver Cliff; from Leadville to Kokomo ; 
from South Arkansas to Gunnison ; from Poncho to Maysville, and from Malta to. 
Eagle River. These extensions aggregate new track, four hundred and forty-six 
miles in length. For the reasons that it has to be accomplished in the face of 
great natural difficulties, through an exceedingly mountainous region and will 
open and make of easy access a region of vast mineral wealth beyond the Conti- 
nental divide; for these reasons the extension to the San Juan has aroused a more 
general and lively interest than the others. » 
From Alamosa the Rio Grande track proceeds to San Antonio, a station 
about two miles from the town of Conejos. At this point the New Mexico branch 
reaches out southward and the San Juan branchjturns toward the west. The dis- 
tance from Alamosa to San Antonio is ieee: miles. The latter station is 
practically the material camp of the Extension company, and the not very thickly 
populated lots and blocks of the town are covered with fields of steel rails, bolts, 
bars, etc., waiting for the demands of the contractors at the front. There are at 
this point or on the line of the road ready to be forwarded, rails sufficient to iron 
sixty miles of track. At present iron is being received at Denver for reshipment 
south, at the rate of one mile per day. 
It is between this point and the Pinos Chama divide, the terminus, that the 
