Meteorological Society. 291 



once in several years. It consists of carbonic acid 38*, soda 40*9, 

 water 20*6, insoluble matter '5, and a trace of a sulphate ; and thus 

 corresponds in composition with the Trona, or striated soda from 

 the Lakes of Fezzan, analyzed by Mr. R. Phillips*, and approaches 

 somewhat nearer to the equivalent numbers of the sesquicarbonate 

 established by that analysis. The water of the Lonar lake contains, 

 besides a little potash, muriate of soda 29 grains, sesquicarbonate 

 of soda 4*2 nearly, and sulphate of soda '1, in 1,000 grains of 

 water. No lime was detected in it, nor any magnesia. The 

 absence of the former Mr. Malcolmson says, is easily accounted 

 for, as the sesquicarbonate of soda and the water itself precipitated 

 the sulphate and muriate of lime, notwithstanding the mutual de- 

 composition they undergo when in a semifluid state. In account- 

 ing for the production of the natron, he adopts the theory of Ber- 

 thollet for the formation of that salt in the lakes of Egypt, viz., a 

 mutual decomposition of the muriate of soda and carbonate of lime, 

 when in a pasty state; but as the natron of Fezzan and the Lonar 

 lake contains half an equivalent more of carbonic acid than can be 

 furnished by carbonate of lime, he proposes a modification of that 

 theory, and suggests that the carbonic acid by which the lime is held 

 in solution in the mud, furnishes the acid, and perhaps indicates the 

 existence of an unstable sesquicarbonate of that substance. * ' Where- 

 ever," adds the author, " 1 have met with natron, or obtained de- 

 tailed accounts of its occurrence, muriate of soda and carbonate of 

 lime existed in the soil, and the natron was found on the surface of 

 the moist earth or mud." 



METEOROLOGICAL SOCIETY. 



Jan. 9, 1838. — A paper on the meteorology of the Island of 

 Teneriffe, lat. 28° 37' N., long. 16° 15' W., by Lieut. Grey (Asso- 

 ciate Member of the Society) in charge of the Australian expedition, 

 was read. 



" The island of Teneriffe," says Lieut. Grey, " is of volcanic origin; 

 and as its famed peak is at the present moment, and has been siijce 

 the island was known to Europeans, in a state of solfatara, I en- 

 tertained a hope that if a series of observations had been made they 

 might possibly throw some light upon the influence that volcanic 

 action exercises upon atmospheric phsenomena." 



Lieut. Grey ascertained that the late Dr. Saviiion of Laguna, a 

 town on the island of Teneriff^e, about 1 800 feet above the level of 

 the sea, and three miles from the shore, had made a series of ther- 

 mometrical observations during a period of eight years (from 181 1 to 

 1818 inclusive) without an interruption of a single day, from which 

 observations a mean of the whole year was obtained of 62'^" 75 Fahr., 

 and 68°-75 Fahr. the mean of July, the month of Lieut. Grey's visit 

 to the island. 



Lieut. Grey immediately caused two sets of observations to be 



* Journal of the Royal Institution, vol.vii. p, 294. 

 2F2 



