NATURAL HISTORY. 203 



tained for examination by rubbing a piece of soft clean paper over the 

 Burtkce aflt'Cted. 



Specimens of all these substances should be gathered, and, when 

 moist, dried tvilhout squeezing. The quantity may vary from a few 

 grains to an ounce, de[)ending on the mode of transportation to be 

 adopted. Eoertj specimen, as collected, should have the dale, locality , 

 def)fh below the sicr/ace, collector, dec, marked imniediatelij upon the 

 envelope. 



It is also very important to collect filterings from river, brackish, 

 and sea waters. To do this, take a circular piece of fine chemical 

 filtering paper, six inches, or thereabouts, in diameter, (the patent 

 blotting paper will answer if the other cannot be procured,) and weigh 

 it caretLilly in a delicate balance. Pass a quantity of the water, vary- 

 ing witli its turbidity^ from a pint to a gill, through the paper, and 

 allow this to dry. Mark the pai)er or its envelope with the original 

 weight of the paper, the amount of water passed through, date, place, 

 &c. It is-desirable to have specimens thus prepared for every locality 

 and for every month in the year. They may be sent, as well as light 

 packages of dried muds, &c., by mail, and should be transmitted as 

 epeedily as possible. 



When the water of lakes and ponds has been rendered turbid by 

 minute green or brown specks, these should be gathered by filtration 

 through ])aper or rag, which may then be dried, or, still better, have 

 this matter scraped ofi" into a small vial of alcohol. 



ON THE FISHES OF NEW YORK. 



BY THEODORE GILL, ESQ. 



New York, April 14, 1856. 

 The Secretary of the Smithsonian Institution. 



SipT: Learning that you were collecting facts in behalf of the 

 Smithsonian Institution with regard to the geogra|)hical distribu- 

 tion, habits, ifec, of the various animals of North America, a short 

 time since I tendered my services to you, through my friend, Mr. 

 John Gr. Bell, and offered to prepare for you a brief list of the fishes 

 observed by me in the markets of the city of New York. This offer 

 Mr. Bell has informed me you were pleased to accept; and I have 

 therefore drawn up such a catalogue, which I now forward to you. 



For u)ore than a year I have, with the exception of one or two in- 

 terru[ttions of shctrt dutaiion, visited Fulton market at least twice a 

 week, and occasionally Washington market. 



As it is intere^*titlg to know Nomething respecting the localities in 

 which the observations recorded were made, although in this case not 

 important, a shoit account is given of the two chief places which have 

 been the theatres of my labors. 



