248 AGRICULTURAL REPORT. 



dard solutiou of mercuric uitrate. As only traces of cliloriuc were present, uo (intima- 

 tion of it was made, and no correction of the results of the determination of tlio urea 

 was necessary except for the dilution of the solution. 



Total dry substance. — This was estimated by keeping a wei{jhcd quantity of the urine 

 at 100^ C. in a tube, while a current of washed and dried air was passed over it, and 

 afterward through a measure^ quantity of standard acid, in order to absorb the am- 

 monia. This operation was continued as long as there was any loss of weight on the 

 part of the residue iu the tube; the amount of ammonia absorbed by the acid was 

 then estimated by the usual titnration, and the weight of the same, calculated as car- 

 bonate, was added to the weight of the residue iu the tube. The amount of ammonia 

 was, however, very small. 



The ash.— A weighed quantity of the urine was carefully charred, the coal was ex- 

 haiisted with distilled water, the aqueous extract liltered out, the coaly insoluble 

 residue burned at a red heat, its ash added to the aqueous extract, the whole evapor- 

 ated to dryness, and the residue gently ignited. 



Phosphoric acid. — This was estimated in a portion of the filtrate from the albumen 

 that was prepared for the determination of the urea, by the volumetric process, with 

 a standard solution of uranic acetate. 



No sugar could be detected in the urine, by digestion with Fehling's solution, 

 Yours, respectfullv, 



G. C. CALDWELL, 

 Professor of Agricultural Chemisinj. 



Professor Law. 



FISH CULTURE. ; 



By Seth GnEEX, Pochester, XeiD Yorl: 

 BROOK TROUT CULTURE.* 



Ill this paper we shall speak briefly of improvements made during the 

 past year, of the increase and present aspects of the business, and give 

 some hints for general information. 



No very great or startling discoveries have been made lately in the 

 science of fish culture. Still there has been a steady advaice in the 

 practice of the art. ]Sfew methods have been discovered o applying 

 known facts; economy of time and labor have be^n well consdered,"and 

 much has been done toward lifting the science from the regioi of experi- 

 ment into that of a paying business. The discovery most tdked about 

 has been that of the so-called dry impregnation, said to ha-^e been dis- 

 covered by a Eussian gentleman, and brought to the knowledge of pis- 

 ciculturists iu this country by Mr. George Shepard Page, of ijfew York. 

 The story of the discovery is as follows : The Eussian gentleman hiving 

 attempted many times to impregnate his eggs in the usual way kiowu 

 to Eussian gentlemen, failed in that way to impregnate more thai a 

 very small percentage. Having made numerous experiments witi a 

 view to a better result, he arrived substantially at the following on- 

 clusions : 



First. That immediately upon its exudation into water, the egg beiig 

 then in a flabby state, commenced to absorb water, and with it milt,'f 

 present ; and that the egg retains its power of absorption of the watc 

 and milt (and consequent impregnation) for a period of about fifteen i) 

 twenty-five minutes after exudation from the fish, the tendency towar* 



^The section on trout culture is written in conjunction with A. S. Collins, my formei 

 partner and successor at Caledonia, New York. 



