158 Intelligence and Miscellaneous Articles. 



tology of the West Indies, and the deficiency of carefully described 

 species of recent corals, were stated to have involved this subject in 

 great obscurity. Dr. Duncan, however, remarked that the paper by 

 Dr. Nugent, published more than forty years ago, showed the exist- 

 ence in Antigua of three consecutive Coral-formations, called by him 

 (in ascending order) — 1, the inclined strata; 2, the Chert; 3, the 

 Marl. 



After describing in detail the seventy species and varieties of 

 Fossil Corals from the West Indian Islands Avhich he had been able 

 to determine, Dr. Duncan exhibited in the form of tables the re- 

 lation which this fossil fauna bears to the existing fauna of the 

 Caribbean Sea, and to that of the Pacific, South Sea, and Indian 

 Ocean, showing that it is more nearly related to the latter than to 

 the former. He also showed that it bears a closer relation to the 

 European Miocene coral-fauna than to the recent West Indian ; and 

 he therefore considered it to be most probably of Miocene age. 

 The author concluded by describing what he believed to be the 

 chief features of the physical geography of the Miocene Period, 

 substituting a series of Archipelagos for the Atlantis of Professor 

 Heer, and stating that the Pacific Ocean must have been at that 

 period in immediate connexion with the Caribbean Sea. 



XXII. Intelligence and Miscellaneous Articles. 



ON AN APPARATUS FOR THE STATICAL MEASURE OF GRAVITY. 



To the Editors of the Philosophical Magazine and Journal. 



Observatory, Trevandrum, 

 Gentlemen, May 21, 1863. 



T SHALL feel obliged if you will publish in your Magazine the ac- 

 -*■ companying translation of a note which I have addressed to M. 

 Elie de Beaumont, Perpetual Secretary of the French Academy of 

 Sciences. 



I am, Gentlemen, 



Your obedient Servant, 



John Allan Broun. 



Ghats of Travancore, India, 

 April 20, 1863. 



Sir, — I have just read a description by M. Babinet of an apparatus 

 for the statical measure of gravity, read before the Academy of 

 Sciences on the 9th of February, 1863. This apparatus was also 

 devised by me several years ago, and it was constructed at my 

 request in 1861 by Mr. Adie, optician, 395 Strand, London. 



Ten years ago I employed a method of determining the coefficient 

 of the bifilar-magnetcmeter scale, in which small weights were added 

 to or taken from the weight of the suspended magnet*. This 

 method induced me to think that the variation of the lunar attrac- 

 tion might have some share in the result found for the effect of the 

 moon upon the horizontal magnetic force. A short calculation proved 



* See 'Report on the Observatories of H. H. the Rajah of Travancore ' 

 (1857), a copy of which was presented to the Academy. 



