British Association for the Advancement of Science. 109 



readings were made every week, and corrected for the tempera- 

 ture of the stem and scale, and the resuks were projected in the 

 form of curves. Among other vakiable results, it is deduced 

 from the observations of 1838, that the oscillations of annual 

 temperature would be virtually extinguished at a depth of 49 

 feet in traf tufa, 62 feet in incoherent sand, or 91 feet in compact 

 sandstone. 



Mr. Snow Harris reported on the progress of the meteorological 

 obse?'vations made by order of the Association at Plymouth, with 

 the barometer and thermometer. The following general results 

 were mentioned. The mean height of the barometer at the Ply- 

 mouth dock-yard, 60 feet above sea level, at 60° F. was from the 

 latest results, 29.8967 in. It occurred in the mean hourly pro- 

 gression four times in the day, viz. at 2h. 20m. and 8h. 10m. 

 A. M. ; and at 12h. 30m. and 6h. 15m. P. M., at which times the 

 waves crossed the mean pressure line. The hours of greatest 

 pressure were 10 A. M. and 9 P. M. — of least pressure, 5 A. M. 

 and 3 P. M. With reference to the influence of the moon on the 

 barometer, Mr. H. had reduced about 4000 of the observations, 

 so as to show the pressure for the time of the moon's southing, 

 and for each hour before and after ; but he could not discover 

 any differences which could be supposed to arise from the moon's 

 influence. 



Dr. Andrew lire described a new Calorimeter, by which the 

 heat disengaged in combustion may be exactly measured, and he 

 gave, also, some introductory remarks on the nature of different 

 coals. In these researches, which are still in progress, the first 

 determination sought is the proportion of volatile and fixed mat- 

 ter afforded by any kind of fuel. This shows how far the coal 

 is a flaming or gas coal, and what quantity of coke it can pro- 

 duce. The second point to be determined is the amount of sul- 

 phur contained in the coals, a matter of great importance, as re- 

 gards their domestic use, their employment by the iron master 

 and the manufacturer of gas. Dr. Ure's future researches are in- 

 tended to embrace every variety of fuel, and the results will 

 doubtless be highly important. 



Prof. Stevelly communicated his method of filling a barometer 

 without the aid of an air-pump ; and of obtaining an invariable 

 level of the surface of the mercury in the cistern. He heated 

 the mercury as hot as it could be used, and filled the tube in the 



