January 10, 1902. J 



SCIENCE. 



57 



depth of a hundred fathoms for the 

 dredge, and three hundred fathoms for the 

 deep plankton net, reached about the limits 

 of practicability. Manila rope nine six- 

 teenths of an inch in diameter was used 

 for all the dredging and deep plankton 

 work. 



HYDBOGEAPHIC APPARATUS. 



The sounding apparatus consisted of the 

 ordinary leads of twelve and twenty 

 pounds weight, galvanized steel vnre, No. 

 10, of the American Steel and Wire Com- 

 pany's grading, and a hand reel, used both 

 for paying out and for reeling in, and for 

 registering the depth. The Miller-Casella 

 thermometer was used for all temperatures 

 below the surface. Surface and atmos- 

 phere temperatures were mostly taken by 

 an ordinary chemical instrument. The 

 bucket for taking subsurface samples of 

 water consists of a brass tube 47 mm. in 

 diameter and 500 mm. in length. The closed 

 lower end is provided with a valve opening 

 inward. The upper end is open during the 

 descent of the instrument, so that the 

 water may pass freely through it. The 

 bucket is attached to the sounding-line 

 above the lead and thermometer, the line 

 being passed through the length of the 

 tube and the middle of its bottom. The 

 instrimient having been sent dovsoi to the 

 depth from which the water sample is de- 

 sired, is then closed by a messenger 

 sent dovsTi on the line. The appa- 

 ratus was not satisfactory, but was the best 

 obtainable under the circumstances. No 

 observations on the composition of the 

 water were attempted, beyond the deter- 

 mination of its specific gravity. For this 

 work the most sensitive hydrometer avail- 

 able was one with a range of scale 1.000 to 

 1.040. This not being sufficiently accurate 

 for wholly reliable results, the main de- 

 pendence was placed upon weighing the 

 water samples. 



It was, of course, impossible to use either 



salinometer or scales on board the launch, 

 but precautions were taken not to allow the 

 water samples to remain long in the bot- 

 tles before being tested. Temperature cor- 

 rections were made in all cases. The 

 salinity observations are the least satisfac- 

 tory, probably, of any of the work seri- 

 ously attempted. The difficulties of this 

 phase of hydrogaphic investigation are 

 well known to all experienced in it; and 

 greater refinement of both appliances and 

 methods than the funds at our disposal this 

 summer would permit would be necessary 

 to make it satisfactory. 



THE LOCATION OF STATIONS. 



An essential feature in such a survey as 

 is here contemplated must be a study of 

 the change in the life of particular locali- 

 ties with the passage of time. The dis- 

 placement of species and groups of species 

 by others through physical or biological in- 

 fluences; their increase in numbers of in- 

 dividuals ; their migrations, etc., are among 

 the most important, but least understood, 

 questions of marine biology. Data for 

 sound generalizations on these questions 

 must meet two general conditions: First, 

 they must be gathered at fairly frequent in- 

 tervals throughout an entire year at least; 

 second, they must be gathered from the 

 same identical spot, so far as this is possible. 

 The locating and picking up of stations be- 

 comes, consequently, a matter of prime im- 

 portance. After consultation with several 

 experienced hydrographers, particularly to 

 be mentioned being Professor George David- 

 son, Mr. Otto Von Goldern, U. S. Engineer 

 Corps, and Lieut. Commander G. C. Calkins, 

 U. S. N., it seemed best to depend upon 

 the sextant for this work. It was believed 

 that greater accuracy could be secured 

 than vdth the compass, and that it would 

 be more practicable and less expensive than 

 the range-pole method. In the hands of 

 Professor Raymond for the first portion of 



