62 Royal Society, 



amount of deviation due to that mass, but found that, instead of the 

 cards crossing, the needles deviated in contrary directions so as to 

 remain in one straight line, as if they had been rigidly connected. 



To obviate this, for the magnet having its unmarked end pointing 

 south was substituted one having its marked end in that direction, 

 but of less power than that of which the marked end pointed north ; 

 and two magnets rigidly connected in the same straight line, with 

 their marked ends remote, were balanced concentric with the other 

 two. The author considers that the result of this combination would 

 be, that this astatic bar would, by the repulsion between its poles 

 and those of the other magnets, take up a position at right angles 

 to the magnetic meridian, the other magnets pointing due north and 

 south. Further, that the north pointing and south pointing ends of 

 the compound needle on the half cards being poles of the same name, 

 that is, both marked, any mass of iron which attracted one end 

 would also attract the other, and thus the half cards which they 

 carried would be caused to cross each other; so that the whole 

 being properly adjusted, the deviations caused by the* iron on the 

 two needles will be equal, and the error of deviation of either one 

 will be half the angle between the two. A figure of this complicated 

 compass accompanies the description. 



In conclusion, the author states that the practicability of rendering 

 the instrument so simple and accurate as to be generally useful, de- 

 pends on experiments and investigations yet to be made ; and 

 then enters upon a calculation, from which, however, no definite 

 results are deduced. 



June 17. — "On the Impregnation of the Ovum in the Amphibia 

 (Second Series revised), and on the direct agency of the Spermato- 

 zoon." By George Newport, F.R.S., F.L.S. &c. 



The author remarks that, having in a former paper shown that the 

 spermatozoon alone is the impregnatory agent, he endeavoured in a 

 subsequent communication to the Royal Society, a report of which 

 is printed in the Proceedings for June 1851, to arrive at some con- 

 clusion as to the nature of its influence ; and, from the facts he was 

 then acquainted with, he announced the view that the spermatozoon 

 appeared to be the organ of a special form or condition of force in 

 the animal body. At that time he had no evidence that the sperma- 

 tozoon penetrates into the coverings of the egg, as he had constantly 

 found it attached only to the surface. Since then he has detected 

 it within the substance of these coverings, and sometimes even par- 

 tially imbedded in the vitelline membrane beneath them ; but he has 

 no evidence that it enters the vitelline cavity. While therefore the 

 fact of penetration into the envelopes necessitates some revision of 

 the details of the view announced, he still regards the spermatozoon 

 as the organ of a special condition or form of force in the animal 

 structure. 



He then proceeds to show the relative duration of vitality in the 

 spermatozoon and the egg, and points out that that of the former 

 is shorter than is usually supposed ; that at the temperature of 

 55° Fabr. it usually is lost in from three to four hours after removal 

 from the body into water ; but that at a lower temperature it is 



