physiologist, Professor Rudolph Wagner, I consider it due to the Royal Society and to myself to call to the Society's remembrance the fact, that, in the memoir above referred to as having been laid before them in 1835, the spot in question is not only pointed out and par- ticularly delineated, but its physiological importance hinted at.
The laying of a paper before a Society is an act of publication. With the communication of my paper to the Royal Society in 1835, the publication of Professor Wagner's paper in Miiller's Archiv was contemporaneous merely.
It is true, that though Professor Wagner's observations were only first published in Miiller's Archiv for 1835, there is a note by the editor, saying that the paper was received by him in 1834 ; but it is also true, — and of this, were it necessary, proof could be easily ad- duced, — that my paper was written also in 1834.
In conclusion, I beg to apologize to the Royal Society for ob- truding on their notice what may appear matter rather of personal than general interest.
3. — Description of the Electro-magnetic Clock. By C. Wheat- stone, Esq., F.R.S.
The object of the apparatus forming the subject of this commu- nication, is stated by the author to be that of enabling a single clock to indicate exactly the same time in as many different places, distant from each other, as may be required. Thus, in an astronomical observatory, every room may be furnished with an instrument, sim- ple in its construction, and therefore little liable to derangement, and of trifling cost, which shall indicate the time, and beat dead seconds audibly, with the same precision as the standard astronomical clock with which it is connected ; thus obviating the necessity of having several clocks, and diminishing the trouble of winding up and regu- lating them separately. In like manner, in public offices and large establishments, one good clock will serve the purpose of indicating the precise time in every part of the building where it may be re- quired, and an accuracy ensured which it would be difficult to obtain by independent clocks, even putting the difference of cost out of consideration. Other cases in which the invention might be ad- vantageously employed were also mentioned. In the electro-mag- netic clock, which was exhibited in action in the Apartments of the Society, all the parts employed in a clock for maintaining and regu- lating the power are entirely dispensed with. It consists simply of a face with its second, minute and hour hands, and of a train of wheels which communicate motion from the arbor of the second's hand to that of the hour hand, in the same manner as in an ordinary clock train ; a small electro-magnet is caused to act upon a pecu- liarly constructed wheel (scarcely capable of being described without a figure) placed on the second's arbor, in such manner that whenever the temporary magnetism is either produced or destroyed, the wheel, and consequently the second's hand, advances a sixtieth part of its revolution. It is obvious, then, that if an electric current can be al- ternately established and arrested, each resumption and cessation
