Arizona republican., 1900-09-10

are so many naVigab!e rivers.
 It is the ingrained waywardnGss of q | river to co very much as it pledses, gouging out an embankment here and filling in channel there, sometimes undermining a tower and often break ing dams and piers placed in its way 10 keep it in order. Vast sums of mon- ey have been spent by all the great na- tions, and spent injudiciously, as the Germans believe, in dredging channels, and in protecting the banks Oi 'ivers. Prof. Engels called attention to our own Mississippi river and spoke of the great cost Of keeping it within bounds, and at the same time of making it sG fe for navigation. In Germany the queS- tion is even more important than it is with us, for he reason that the country is more dcnseIy peopled, the land is more valuable and changes in the course of flow in a river are therefore more destructive and costly. More over, the rivers of Germany are not, generally speaking. so swift and long as they are iii America, and it is need less to keep tEem at the height of ef- fectivenees as 10 navigability.
 It was with this idea of bringing sci entific methods to bear on these prob lens that the Flussbau Laboratorium was established about three years ago. Prof. Engels began his work in the typical German way-that is, by invss-
 tigating his subject thoroughly in the weight of science before attempting to offer practical suggestions. A large
 room is set aside in the basement of the Dresden Technical school, and here, elevated some four feet from the floor, Prof. Engels has had constructed an
 iron trough or tank about seven feet in width and two feet deep, reaching the full length of the room. At the up per end of this trough a large river
 tank is placed. with appliances for per
 hitting the water which 1t contains to flow into the trough in any required
 volume in such a way that it will eX-
 actly iInita te the even flow of a river
 The experimental trough is filled to| some depth with sand and the course of Q river is laid out, angling down the
 trough through the sand. It is at first of even depth throughout, and the
 banks are protected by small bags of
 shot Into this miniature river the
 water is allowed to flow at a given speed, and Prof. Engels studies closely
 all those places where the sandy bot
 tom is washed out, where it is filled in,
 where the banks have a, tendency to
 cave away and where new banks are
 building up. As the water flows IL
 naturally carries much sand entirely
 out of the trough. All this is caught
 and preserved in a most ingenious
 manner. A the water leaves the
 trough it is carried over tin ribs, be-
 hind which the sand is deposited. final
 ly falling. entirely clear of all soil, inso
 a large tank at the lower end of the
 trough. Here a pump is constantly at
 work driving the water which thus
 comes through the "river'' back to the
 upper tank, thus using it over and over
 and enabling the river to flow on with
 out interruption for weeks.
 Prof. Engels showed me sands of va
 ricu5 colors which he used for showing
 the exact position of deposit of sand
 wash in his rivers. A red sand fed
 slowly into the mouth" of the river
 would show in bars and banks half
 way Cown or more, indicating exactly
 where the river was. at any given time,
 adding land. 4 little later. blue sand
 used in the same way might show the
 fuirati0n CT still other bars, and the
 removal of the red sand bars previ-
 oUsly produced. Controlling the water
 as he does. Prof Engels can have a
 freshet at any time he sees fit. noting
 it's effect on his r:ver, or he can initiate
 the sluggish flow of dry autumn. If his river is exceedingly crooked he can produce a new channel artificially as it
 might be produced by a sudden great
 flushing of water, and he can build dams, br5akwaters, piers, docks, bridges. and so or, and note in each case the effect which these produce Cn 1 the river. whether they tend to deepen
 or to obstruct the channel, the iniiu- ! ence of each as regards the formation of bars and banks, and so on, and how deeD piling must be driven to escape under washing by burrowing river all facts of the utmost importance to 1 engineers. The sand washed entirely ! out of the trough and caught by the tin ribs can | ? gathered up and meas ured the quantity thus obtained fur nisning valuable data as to the rate Cf | deposit of rivers of various volume and | velocity Of flow. Prof. Engels also ! studies the effect of flow not only in rivers having sandy channels, but he also uses gravel and stone, construct l ing islands and gravel ribs, and watch l ing the effect of each on the river.
 ! Many of the rivers of Germany have | been plotted with great accuracy not i only as to their shore lines. but with | regard to the contour of their channel
 beds. With these maps and contours | in hand Prof. Engels is now engaged in | laying out to an exact scale various | sections of the more important German rivers. He duplicates exactly every curve, builds in every crib and break water. and then turns on the water at 1 the ordinary rate of flow of the river under inves tigation. When l visited the laboratory a stretch of the Eibe | hld just been completed, and a beauti- fully neat piece of work it was, the
 cribs all accurately placed and the | banks held in place with bags of shot. | Tie water was turned on. and Prof. ! Engels indicated With great enthusias n
 where the bars were, being built up, where the channel was deepening, | where holloWs were being filled in, and
 90 on. Then he proceeded to indicate