264 Proceedings of the British Association 



of the suggestions should be complied with, as far as possible. There 

 is only one subject of regret connected with this remarkable eclipse, 

 namely, that it will deprive us of the assistance of several astronomers 

 who would undoubtedly have joined this meeting but for the necessity 

 of being ready, at definite points, for the observation of the phenomena. 



Among subjects related in some measure to astronomy, I may first 

 allude to M. FoucauU''s experiment on the rotation of the plane of a 

 simple pendulum's vibration ; an experiment which has excited very 

 great attention both in France and in England, as visibly proving, if 

 proof were necessary, the rotation of the earth. It is certain that M. 

 FoucauU's theory is correct ; but it is also certain that careful adjust- 

 ments, or measures of defect of adjustment, are necessary to justify 

 the deduction of any valid inference. For want of these, the experi- 

 ment has sometimes failed. The Council of the Association have long 

 regretted the very great delay which has occurred in the publication of 

 the geodetic results of our great National Survey ; and they were pre- 

 pared some time since to represent strongly to the government the ex- 

 pediency of taking immediate steps for complelincr the few calculations 

 which yet remained to be made, and for publishing the whole in a form 

 which should be available for discussions of the figure of the earth. 

 On communicating with the Royal Society, they learned that that body 

 had made an urgent recommendation to the same tenor, and that in 

 consequence, government had consented to place on the estimates a 

 sum of money expressly for the purpose of completing and publishing 

 the scientific portions of the survey. I have received official informa- 

 tion that this work is now in active progress; and I cannot but remark 

 on it as a striking instance of how much may be sometimes effected 

 for the purposes of science by simply completing what is nearly com- 

 plete. The great Swedish and Russian Arc of Meridian, from the 

 North Cape to the Danube, is so far advanced that its completion is 

 expected in the present year. 



At the last meeting of the Association, a Committee was appointed 

 expressly to urge on the government, what had long excited the alien- 

 lion of the Association, the defective state of the survey as regards 

 Scotland. I am happy in stating that there is strong reason to hope 

 that a large sum will in future be appropriated to the Scotch Survey- 



The next subject to which the influence of the Association was ener- 

 getically directed is, Terrestrial Magnetism ; with which Meteorology 

 has usually been associated. Although the active employment of sev- 

 eral of the Colonial Magnetic and Meteorolooical Observatories has 

 terminated, (those only of Toronto, Hobarlown, Cape of Good Hope, 

 Madras and Bombay being retained, and only in partial activity,) the 

 work connected with them has not yet ceased. Much has yet to be 

 done in the printing and discussion of the observations: — a work going 

 on under the care of Col. Sabine. In tacit association with the repre- 

 sentative of the government, the agents of the Association are employed 

 at the Kew Observatory, under the superintendence of Mr. Ronalds, in 

 devising or examining new instruments. The Daguerrotype method 

 of self-registration (which is perhaps liable to this objection, that the 

 original records are destroyed) has been extended to the vertical-force 

 instrument. Apparatus has been arranged for the graduation of original 



