26 



SCIENCE. 



[Vol. VII., No. 153 



nations, 

 suits : — 



The following table exhibits the re- SUCCESS IN 



HATCHING THE EGGS OF 

 THE COD. 



Station. 



Distance 

 in 

 miles. 



Interval 

 of trans- 

 mission. 



Velocity 

 in miles 

 per second. 







Willot-'s Pninf T, f 



*» lllvrU o l uiiii, u.x.. ... 



Pearsalls, " 



Bay Shore, " .... 

 Patchogue, " 



8.33 

 16.78 



00. DO 



48.52 



8.5 

 66 



15.4 



0.98 

 2.54 



4, 0~ 



3.15 



Goat Island. R.I 



Harvard obs'y, Mass. . 



144.89 

 182.68 



58.8 

 219.8 



2.46 

 0.83 



West Point, N.Y 



42.34 



I 13.6 

 1 10.9 

 I 10.9 



311 



3.88 

 3.88 



Hamilton coll., N.Y.... 



174 37 



( 45.0 

 1 45.2 



3 88 

 3.86 





484- 



51 



0.94 





These wave velocities are any thing but accord- 

 ant, and no satisfactory reason can be given for their 

 variation ; but they all agree in showing velocities 

 that are higher than those deduced from observa- 

 tions on natural earthquakes ; and from this Gen- 

 eral Abbott feels confirmed, in his deductions from 

 the explosions of certain torpedoes and at Hallett's 

 Point in 1876, that the more violent the initial 

 shock, the higher is the velocity of transmission. 

 At Flood Rock the charge was about six times as 

 great as at Hallett's Point, and the velocity was 

 from two to three times as great, over essentially 

 the same route. Beyond this, the generalizations 

 are not satisfactory. It is true that the velocities 

 through Long Island, which is largely built of un- 

 consolidated drift, are, on the whole, less than the 

 accordant series up the Hudson valley, through 

 rock ; and the Goat Island and Harvard velocities, 

 which must have been almost entirely through 

 rock, seem to show a falling-off in the transmis- 

 sion as the wave weakened over increasing dis- 

 tune e. But Hamilton is almost as far as Harvard, 

 and yet its velocity is as great as at West Point ; 

 and Princeton must have felt a rock-wave at a 

 moderate distance, and still its velocity had about 

 the rate of that at Willet's Point and Harvard, 

 which are very dissimilarly situated. It certainly 

 cannot be thought that the initial velocity was 

 slower than that at any later moment, except in 

 so far as the nature of material traversed would 

 affect it : therefore the apparent increase along 

 Long Island should he looked for in the less per- 

 centage of distance traversed through the drift in 

 reaching the further stations. But beyond this 

 suggestion, hypothesis wanders too freely; and, 

 Etnleafl the stations yet to be heard from solve the 

 question, the explosion at Flood Rock has hardly 

 taught us more than that earth-waves are very 

 complicated, and that there is yet much to learn 

 about them. 



For four seasons experiments have been carried 

 on for the purpose of discovering a practical 

 method of hatching out the eggs of the cod, — one 

 of the most fertile and valuable of the food-fishes 

 found off our coast. During the period mentioned 

 no less than forty forms of apparatus have been 

 devised and operated, with varying success, by 

 different persons connected with the work of the 

 IJ. S. fish commission. Up to the present time no 

 device has fulfilled the required conditions, even 

 approximately, with such success as the apparatus 

 just devised by H. C. Chester, superintendent of 

 the Wood's Holl station, of the commission. 



This apparatus is essentially automatic, and 

 needs so little attention that one man will by its 

 aid readily care for a hundred million eggs. It 

 consists of a trough seven feet six inches in length, 

 two feet in width, and two feet four inches in 

 depth. At about one foot from either end, ver- 

 tical wooden partitions, extending to within four 

 inches of the bottom of the trough, are secured. This 

 leaves a space about five feet six inches in length 

 between the partitions. In this space six or eight 

 large glass jars are supported upon a frame, with 

 their tops downward. Those used for the purpose 

 at Wood's Holl are ordinary cylindrical, four- 

 gallon specimen jars, with a half -inch hole drilled 

 in the centre of the bottom. The stoppers of the 

 jars are removed, and a single thickness of coarse 

 cheese-cloth is secured over the mouth w T ith strong 

 twine. The jar is then inverted, and lowered into 

 the trough, so that its bottom is about even with 

 the top of the trough. Strips nailed across the top 

 of the trough serve to keep the jars upright. 



The accompanying figure, showing the device in 



rfa 



longitudinal vertical section, modified and designed 

 on a somewhat smaller scale than the device now 

 in use, and accommodating only four jars (two in a 

 row), will enable the reader to get a clear concep- 

 tion of the way in which the apparatus is used. 

 The trough A is filled with unfiltered sea-water 



