126 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



coal. None of the waste products in this establishment are utilized, all 

 being discharged into the river by a sewer at the foot of G street. The 

 amount discharged is not less than 100 gallons per minute, and carries 

 with it a considerable portion of the same oily residuum that has been 

 already mentioned as coming from the establishment for the utilization 

 of the coal tar products. 



The characteristics of this substance are such that in the ordinary ebb 

 and flow of the tides it must be very widely disseminated over the bot- 

 tom of the river. As it comes from the sewer it seems to be lighter than 

 the water, and floats off in a dark stream along down the shore. Agi- 

 tated for a while by the rippling of the water, it sinks ; this result being 

 due either to the fact that the cohesion of the layer is broken, or more 

 probably that becoming incorporated with the mud and sediment, its 

 specific gravity is increased to such a slight extent as to be hardly ap- 

 preciably heavier than the water in which it is floating. These peculiar 

 characteristics must necessarily determine its general distribution over 

 the bed of the river in front of Georgetown, and in a lessening quantity 

 as far down as the limits of the District extend. 



We are confronted, therefore, with the fact that this substance, so 

 generally distributed over the bottom of the river, may and doubtless 

 does influence unfavorably the conditions of life for all those minute 

 forms which have their nidus on the bottom, and which furnish the sub- 

 stratum or basement upon which the existence of higher forms of life 

 in the river necessarily depends. The abundant organic life which 

 flourishes in the ooze upon the bottom furnishes the food of the minute 

 forms which float or swim in the water above, and which, in their turn, 

 furnish the food for the young of fish such as the shad, herring, rock, 

 perch, &c. 



It is evident, therefore, that even if the discharge of waste products, 

 such as have been above enumerated, into the river should seem to have 

 no injurious effect in driving the larger fish from the river, yet indi- 

 rectly, by modifying unfavorably the conditions of the bottom, it may, 

 by destroying their food, make impossible the development and growth 

 of the embryo fish, which must be nurtured in this area in quantities 

 sufficient to keep up the annual supply for the fisheries. 



It is, in my opinion, absolutely necessary, in connection with the leg- 

 islation now contemplated in reference to the fisheries in the District 

 of Columbia, to prohibit absolutely, and under severe penalties, the dis- 

 charge of gas tar or other waste chemical products into the Potomac. 

 It is useless to protect the spawning of the shad and herring in District 

 Maters if we at the same time permit the conditions which determine 

 a sufficient supply of food for them in the waters to be unfavorably 

 influenced by the pollution of the stream by these products. 



Washington, D. 0., May 19, 1884. 



