SCIENCE. 



233 



forests, houses, other property are borne down stream. 

 One gorge alone has been known to sweep away $3,000,000 

 worth of property, besides making a tremendous destruction 

 of life. A gorge will often require three days to pass a 

 given point. 



Another enemy to investigation and to embankments are 

 the snags which infest the river. These, in their worst form, 

 are large trees with roots and limbs. So rapidly are they 

 loosened and borne down that the government is required 

 to keep several snag boats constantly at work. Perhaps the 

 greatest of all enemies to embankments is the period of 

 high water. At this time most of the country adjoining the 

 river, known as the " bottom lands," is flooded to a greater 

 or less depth. This is a most dangerous period, the result 

 of which is awaited with anxiety by land-owners involved. 

 The various floods occurring since 1850, principally in that 

 year, and those of 1864 and 1874, have carried away 200 

 miles of embankment between New Orleans and Cairo 

 alone, which will cost the government alone $6,000,000 to 

 repair. 



There are many schemes offered for the construction of 

 permanent embankments. Some are practicable to an 

 extent, and others are but empty air. It is 

 evident, however, that the government can never 

 secure sufficient funds to inaugurate a system of em- 

 bankments which shall have a foundation resting on the 

 bed-rock below the river's bottom. Captain Charles 

 M. Scott proposes a method which is, in brief, to weight 

 and sink a reach of trees with their roots in such a manner 

 as shall change or keep the current within bounds. A 

 careful consideration of this method shows that after every 

 high-water season these trees would be " reaching " in all 

 directions along the river. Captain James B. Eads once 

 proposed a system of ditches which shall narrow the river 

 in wide places and compel the current to cut a deeper 

 channel. As I understand this method, it is hardly practi- 

 cable. There are other methods proposed. That of Cap- 

 tain Cowden is, perhaps, worthy of trial, though I am com- 

 pelled to believe that it must be accompanied by a perma- 

 nent system of levees. A very simple method, which has 

 a semblance of practicability, is being experimented on 

 near Omaha and at Nebraska City by Major C. R. Suter. 

 An examination of this exhibits a simplicity which may 

 circumvent the action of the water. No rip-rap is sunk and 

 no piles are driven down. The sloping bank is covered 

 with a mattress of brush. Stones are piled on this to a 

 thickness of seven or eight feet, which holds the bank in 

 its place and retains its sloping form. The water seems to 

 have little inclination to work under this as in the case of 

 a perpendicular embankment. I believe it is the invention, 

 for the most part, of Professor L. E. Cooley, late professor 

 of Engineering in the Northwestern University at Evanston, 

 111., and now in charge of the works at Nebraska City, 

 Major Suter also employs a simple and inexpensive method 

 of changing the current of the river where it is wearing 

 away the bank. A line is fastened to a buoy near the cen- 

 tre. Branches of trees are tied along one-half of this, 

 leaving the other half bare. Anchors are attached at both 

 ends of the rope and the half without bushes is run up the 

 river as a guy, while the buoy holds up the centre of the 

 rope at the surface. A line of brush then runs from the 

 surface diagonally to the bottom. A series of these is 

 placed out in the stream near where the damage is being 

 done. The sediment coming down stream catches on the 

 brush, sinks and forms a bar, and either breaks the force 

 of the current or throws it out into the stream away from 

 the endangered bank. This latter method has long been in 

 use by the Corps of Royal Engineers with success. 



Hegar's formula for an effective non-poisonous preserva- 

 tive and antiseptic is as follows : 



I£ Salicylic acid 20 parts. 



Boracic acid 25 " 



Potassium carbonate 5 " 



Dissolve in hot water 500 " 



Glvcerine 200 " 



Then add oil of cinnamon, oil of cloves, each 



15 parts, dissolved in alcohol 500 " 



It is an exterminator of moths and vermin and has a 

 pleasant odor. 



ON THE NUTRITIVE VALUE OF FISH.* 



By Prof. W. O. Atwater. 



This paper gives the results of an investigation made 

 under the auspices of the Smithsonian Institution and the 

 United States fish commission. They included analyses 

 of a large number of specimens of more common food 

 fishes, whose details, though quite extended, were mainly 

 of theoretical value. Some of the applications, however, 

 were of much practical interest. In 100 pounds of the flesh 

 of fresh cod we have 83 pounds of water and only 17 pounds 

 of solids, while the flesh of the salmon contains only 66^ 

 per cent, of water and 33^2 P er cent, of solids ; that is to say, 

 about one-sixth of the flesh of cod and one-third of that of 

 salmon consists of solid, that is, nutritive substances, the 

 rest being water. Lean beef, free from bone, contains 

 about seventy-five per cent, water and twenty-five per cent, 

 solids. The figures for some of the more common sorts of 

 fish were : 



Solids, 

 per cent. 



Flounder 172 



Cod 16.9 



Striped bass 20.4 



Kluefish 21.8 



Halibut, lean ." 20.6 



Solids, 

 per cent. 



Halibut, fat 30.7 



Mackerel 22.2 



Shad 30. 7 



Whitefish 30.4 



Salmon 33.6 



If we take into account not the flesh only but the whole 

 fish as sold in the market, including bones, skin and other 

 waste, the actual percentages of nutritive material, is, of 

 course, smaller. Thus the following percentages of edible 

 solids were found in samples analyzed : 



Flounders 7.1 Shad 14.8 



Cod 10.5 hhad _ 18.7 



Mackerel 11.4 Lake trout 13.6 



Halibut, lean 15.6 Salmon 25.6 



Halibut, fatter 27 2 



The subject has of late attracted unusual attention. The 

 chemico-physiological investigation of the past two decades 

 has brought us where we can judge with a considerable 

 degree of accuracy from the chemical composition of a 

 food-material what is its value for nourishment as compared 

 with other foods. The bulk of the best late investigation 

 of this subject has been made in Germany where a large 

 number of chemists and physiologists are busying them- 

 selves in the experimental study of the laws of animal nutri- 

 tion. They have already got so far as to feel themselves 

 warranted in computing the relative values of our common 

 foods, and arrange them in tables, which are coming into 

 popular use. The valuations are based upon the amounts 

 of albuminoids, carbo-hydrates and fats, each being rated at 

 a certain standard, just as a grocer makes out his bill for a 

 lot of sugar, tea and coffee, by rating each at a certain price 

 per pound, and adding the sums thus competed to make the 

 whole bill. A table was given showing the composition of 

 alist of animal foods. Thus it appeared that, while medium 

 beef has about three-fourths water and one-fourth solids, 

 milk is seven-eighths water and one-eighth solids. Assum- 

 ing a pint of milk to weigh a pound, and speaking roughly, 

 a quart of milk and a pound of beefsteak would both con- 

 tain the same amount — about four ounces — of solids. But 

 the quart of milk would not be worth as much for food as 

 the pound of steak. The reason is that the nutrients of the 

 steak are almost entirely albuminoid, while the milk con- 

 tains a good deal of carbo-hydrates and fats, which have a 

 lower nutritive value. According to the valuations given, 

 taking medium beef at 100, we should have for like weights 

 of flesh free from bone : 



Medium beef 100. o 



Fre-h milk..- 23.8 



Skimmei milk 18.5 



Butter 124.0 



Cheese 155.° 



Hens' eggs 72.0 



Cod (fresh fish)... 68.0 



Flounders 65.0 



Halibut 88.0 



Striped bass 79.0 



Bluefish 85.0 



M ackerel 86.0 



Halibut 88. c 



Lake trout 94.0 



Eels qc.o 



Shad 



99.0 



Whitefish 103.0 



Salmon ._ 104.0 



Salt mackerel m.o 



Dried codfish 346-0 



These figures differ widely from the market values. But 

 we pay for our food according, not to their value for nourish- 

 ing our bodies, but to their agreeableness. Taking the 

 samples of fish at their retail prices in the Middletown, 

 Conn., markets, the total edible solids in suiped bass came 

 to about $2.30 a pound, while the Connecticut river shad's 



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



