The Birmingham age-herald., 1904-01-22

lions until it is finally met by the resist anee of tho solid foundations upon which the last section rests. Tho bridge builder. therefore, may have to penetrate fnr be- low the surface of the earth or tho bottom of river before he begins 10 build up nls arches and as n matter Of fact the volume of masonry that Is covered up and out of sight is not infrequently greater than what Is visible. Every stone in true arch" is a link in the chain which transmits and supports the downward pressure of whatever weight or material or of humanity may be placed above IL It's construction naturally demands q thorough knowledge of the method of pre- paring a firm foundation and both ths ancient Hindoos and Egyptians, lacking complete confidence in their knowledge of this important factor in arch construction argued that the sleepless thrust or the arch might easily become a force slowly tearing into pieces. and used the aren very sparing1y indeed in consequence.
 The modern Brother of the Bridge learns more about foundations than even the ancient Romans, many of whose bridges are still standing and likely wlth proper caretaking, to ontlast many future centuries. and he knows also more about testing his material during the process of construction. Just how these ancient bridge builders got their preliminary training is unknown but 1t Is an interest ing fact that in a later period both Leon ardo da vinei and Michael Angelo were practical engineers as well as artists The modern bridge builder on the other hand is invariably the product of techno= logical instruction, the first school of engineering having been established In France in 176O, when an old French draw ing school became the "Ecole des Fonts ct Chaussees'' and was put in charge or the noted contemporary engineer Perfo- net. Since that time the greater part of the public works of France have been built by graduates of that school, Just as many of the important engineering problems of America are now in the hands of graduates of the Massachusetts Insti- tute of Technology or those of Germany are under the supervision of men who got their training at Charlottenberg.
 Perhaps the most interesting minor fact about these mighty structures, with their series of graceful arches, is that the man who designs them must be able to see the finished bridge in all its perfec- tion by an effort of the imagination based upon geometrical drawings of the differ ent parts. At the institute for example the future bridge builders have access to a group of models Illustrating the differ- ent kinds of arches and other forms of bridges with which they must become fa- miliar. but these models are very little used in instruction. The student is taught to "yisualize" his completed bridge from the moment when his plans begin to take form on paper, and he must not only plan the shape and dimensions of every block of stone that goes to make his arch but he must be able, eventually to feel almost by instinct how the proportions of the arch will look when actually com peted. And this planning of the actual bridge is only one part of his education for he must know how to test each kind of material and how to find or provide a foundation that shall be absolutely trust worthy. We might even say for that matter that old Atlas, whom the aneients believed supported the world on his shoulder, made a true arch of his legs in order to support 1t.