232 



SCIENCE. 



The path along which they walk is a path which they did 

 not engineer. It is a path made for them, and they simply 

 follow it. But the propensities and tastes and feelings 

 which make them follow it, and the Tightness of its direc- 

 tion towards the ends to be obtained, do constitute a unity 

 of adjustment which binds together the whole world of 

 Life, and the whole inorganic world on which living things 

 depend. 



I have called this adjustment mechanical, and so, in the 

 strictest sense, it is. We must take care, howtver, not to 

 let our conceptions of the realities of Nature be rendered 

 indistinct by those elements of metaphor which abound in 

 language. These elements, indeed, when kept in their 

 proper places, are not only the indispensable auxil aries of 

 thought, but they represent those perceptions of the mind 

 which are the highest and the most absolutely true. Thty 

 are the recognition — often the unconscious recognition--of 

 the central unities of Nature. Nevertheless, the)' are the 

 prolific source of error when not closely watched. Because 

 all the functions and phenomena of Life appear to be strictly 

 connected with an apparatus, and may therefore be regarded 

 as brought about by adjustments which are mechanical, 

 therefore it has been concluded that those phenomena, even 

 the most purely mental, are mechanical in the same sense 

 in which the work is called mechanical which human ma- 

 chines perform. Are not all animals "automata?" Are 

 they not " mere machines?" This question has been re- 

 vived from age to age since philosophy began, and has been 

 discussed in our own time with all the aid which the most 

 recent physiological experiment can afford. It is a question 

 of extreme interest in its bearing on our present subject. 

 The sense in which, and the degree to which, all mental 

 phenomena are founded on, and are the result of mechani- 

 cal adjustments, is a question of the highest interest and 

 importance. The phenomena of instinct, as exhibited in 

 the lower animals, are undoubtedly the field of ob?eivation 

 in which the solution of this question may best be found, 

 and I cannot better explain the aspect in which it presents 

 itself to me, than by discussing it in connection with certain 

 exhibitions of animal instinct which I had occasion to ob- 

 serve during the spring and summer of 1S74. They were 

 not uncommon cases. On the contrary, they were of a kind 

 of which the whole world is full. But not the less directly 

 did they suggest all the problems under discussion, and not 

 the less forcibly did they strike me with the admiration and 

 the wonder which no familiarity can exhaust. 



IMPROVEMENT OF THE MISSISSIPPI RIVER.* 

 By Pkof. W. H. Ballou. 



The Mississippi River is the most gigantic parasite 

 known to men. The least possible estimate, computed 

 from data in hand, shows that the annual average for the last 

 thirty years, of money exp< tided ( n it for improvements, 

 and lost through its depredations, exceeds $7,000,000. 

 Fully one-thud of this sum is used by the government, 

 States and private individuals to keep the stream and its 

 tributaries in an ''improved .condition." The table will 

 show the average of the expenditures obtained for the last 

 thirty years : 



Expenditures of the- States of Mississippi, Louisiana and 

 Arkansas on levees since 184Q. $100,090,000 



Expended by 'he government and private individuals — 

 estimate _.. _ _ 50,000,000 



Damage by floods, ice gorges, etc., to levees, property, life 

 etc . 80,000,000 



Total $230,090,000 



Average per annum, $7,660,61 6. 



To this may be added 26,772.379 acres of land granted to 

 the above States l>y the governmtnt in 1849, the value 



being about $10 per acre. 2C7,77l,7' ; o 



To,al ---- $497.8i3,7<,o 



Average per year, >!'">,<>■. 



Only those who are acquainted with the stream audits 

 peculiarities have an idea how unmanageable it is. The 

 unstable t ondition of the soil of the country through which 

 it Hows renders it an object of distrust to the inhabitants of 



its border. Such is the Heat heiotis (ondition of its rela- 

 tions that for sixty-two years the ingenuit) of man has con- 

 trived no check on ii action, The causes of this condition 



* Read before the A. A. A. S., Boston, 1880. 



of things are found partly in the river-bed. The sedimen- 

 tary deposit varies from 60 to 100 feet in depth. It is gen- 

 erally composed of silt, with a mixture of clay and sand, 

 which, having been deposited by the river, is at its disposal 

 to lie still or be shifted about. It is evident that no ordi- 

 nary construction can long stand unless it has a foundation 

 penetrating this bed to a rock stratum. The great bridge 

 at St. Louis, for instance, has its piers resting on the lime- 

 stone bed-rock, under a sedimentary deposit of seventy 

 feet. The railway bridge at the mouth of the Minnesota 

 river has its piers lodged on a slender stratum of hard earth 

 sixty feet beneath the river's bottom. It is further admitted 

 that in boring through this stratum a soft layer was struck, 

 which would not uphold the red's weight. At Cairo, 111., 

 in 1877, the United States corps of engineers, under Lieu- 

 tenant D. W. Lockwood, made borings to a depth of 87 

 feet without encountering any stratum harder than sand. 

 At this point the machinery broke down and operations 

 were suspended. At a depth of 33 feet the auger pene- 

 trated a Cottonwood log, hardly ready to decay, showing 

 conclusively the facility with which the river makes its own 

 bed. At the same place it is stated on good authority that 

 piles, one on another, have been driven to a depth of 125 

 feet without encountering a rocky stratum. 



The story of its great width is even more remarkable. 

 Near Cairo, 111., the river moved a mile out of its course in 

 one year, and is continually changing at that point. Still 

 more remarkable are the operations of the Missouri river. 

 At one time Council Bluffs enjoyed its presence in the im- 

 mediate proximity, and the benefits of its commerce, in conse- 

 quence of which the city became the terminus for Western rail- 

 ways in preference to Omaha, three times its size. These rail- 

 roads erected depots and stationed offices of general Western 

 superintendents there. The Union Pacific constructed an 

 immense bridge, and in common with other railways built a 

 union depot at the Bluffs. No sooner was the work com- 

 pleted, than the Missouri performed the rare feat of moving 

 its course to Omaha, three miles away. There is no end to 

 instances of this kind on a smaller scale. It may be safely 

 asserted that from its narrowest point the Mississippi varies 

 to twenty miles in width. It is no wonder, then, that the 

 present embankment system is inadequate. Appropriations 

 are only asked at present for embankments as far north as 

 Cairo. It is evident, however, that the sedimentary bed ex- 

 tended nearly to the source of the Mississippi, and that 

 not only must the no miles from New Orleans to Cairo be 

 embanked, but also the greater shore line above the latte 

 city on both this river and the Missouri. An explanation 

 of the frequent destruction of levees, dikes and embank- 

 ments is found in the method of their construction. When 

 the current leaves the middle and runs along one side of 

 the stream, the bank is rapidly torn down. At this point 

 the corps of engineers proceed to build a dike to resist the 

 destructive force. A rip-rap is first constructed which con- 

 sists of a raft covered with long poles, placed cross-wise in 

 alternate layers. This is loaded with heavy stones and 

 sunk near the shore. Outside of it long poles are driven 

 to a depth of twenty or thirty feet, and sometimes to twice 

 these depths. Brush and stones are heaped upon their 

 foundation until a perpendicular embankment is completed 

 on a level with the top of the bank. One would think that 

 this ponderous dike would stand for ages. But so vaccil- 

 lating is the silt bed underneath that the water keeps work- 

 ing the outer edge with powerful results. The embank- 

 ment settles, sometimes '.oppling over, and again dropping 

 suddenly from sight. Often the water works in behind 

 these constructions and leaves them out in the stream. 

 Thus it happens that the river is at work at innumerable 

 points, tearing away its banks and defying the structures 

 in use to hold it in check. 



In its work of destruction the current has some formid- 

 able aids. In the winter ice floats down continually. So 

 immense are these cakes at limes that three, and even two 

 coining down stream abreast will get caught on the sides of 

 the river, in some narrow channel, and form a bridge. This 

 bridge effectually holds back all oncoming ice. The great 

 and small cakes coming down in large quantities join 

 under, over and behind the bridge, piling up to a great 

 height, forming a gigantic gorge. This mass finally breaks 

 away ; no powei ye( inaugurated by the hand of man isable 

 to withstand it. Embankments, boats, live stock, people, 



