Intelligence and Miscellaneous Articles. 153 



Observatories, and also of the temperature at the Cape, St. Helena, 

 Hobarton, Toronto, Greenwich, Leith, and Melville Island. The 

 author infers that the temperatures taken at six-hourly intervals give 

 for their sum four times the mean temperature of the day, ivhateverbe 

 the commencing hour ; and thus travellers and voyagers observing at 

 5\ ll*", 17''and23'", will get the mean temperature of their position at 

 2 P.M. Hence, from the communications of the captains of Merchant- 

 men, the Atlantic oceanic temperatures might be mapped in the 

 course of a j-ear, and the isothermal curves on this broad level sur- 

 face be accurately laid down (see Journ. R. Geograph. Soc. ix. 

 p. 369). Excepting at Melville Island, Rj is the greatest coefficient, 

 i/*, is nearly constant, and 



H + Sf R,. sin (?7 + 1//;) + cos 8 ^ cos 2 t (F sin i + G cos 

 will give the yearly formula : the homonymous hours are expressed 

 by H + 2^ R/ sin (it-\--^i) as in the oceanic tides nearly. At Melville 

 Island, i//3=45° nearly and R, is the greatest. The semester from 

 midwinter to midsummer is also nearly expressed by 



P + Q sin ©long, for Rj. 

 Having obtained the empirical R and ;//, or A and a, any theoretic 

 formula can be tested by the results. 



XXIII. Intelligence and Miscellaneous Articles. 



RESEARCHES ON THE SULPHURETS WHICH ARE DECOMPOSABLE 

 BY WATER. BY E. FREMY. 



'T'HE object of this paper is to make known the production and 

 ■■ principal properties of a class of sulphurets hitherto little ex- 

 amined, and the study of which is alike interesting to chemists and 

 geologists, from the light which it throws on the formation of 

 mineral waters. 



When we consider the action of water on the sulphurets. we find 

 that these compounds may be divided into three classes : the first 

 comprises the sulphurets of the alkalies and of the alkaline earths 

 which dissolve in water ; the second is formed of the insoluble sul- 

 phurets ; the third consists of the sulphurets of boron, silicon, mag- 

 nesium and aluminium, which are decomposed by water : these latter 

 are scarcely known, owing to their preparation having hitherto been 

 accompanied with great difficulties. In order to a thorough inves- 

 tigation of all the questions which arc connected with the decom- 

 position of the sulphurets by water, I first sought for a method by 

 which they might be easily prepared. This method I will now describe. 



It is well known that sulphur exerts no action upon silica, boracic 

 acid, magnesia and alumina. I imagined it might be possible to 

 replace the oxygen in these substances by sulphur by the interven- 

 tion of a second affinity, as that of carbon for oxygen. Such decom- 

 positions, produced by two affinities, are not rare in chemistry ; and 

 in some yet unpublished experiments on the fluorides, I had observed 

 that the suljjhurct of carbon completely decomposed the fluoride of 

 calcium mixed with silica, i)roducing sulphuret of calcium. I was 

 therefore led to presume that flic sulphuret of carbon, acting by its 

 two elements upon the preceding oxides, would remove the oxygen 



