Meteorological Observations, 159 



The specific gravity of liquid carbonic acid is so variable tbat, 

 from 32*^ to 86° Fahr., it runs through the scale of density from 

 water to the aethers. Its dilatibility, the pressure and weight of its 

 vapour, are four times greater than that of atmospheric air; its ca- 

 pillarity, and particularly its compressibility, are a tlrousand times 

 greater than that of water. From these.faCts the author has been led 

 to a uniform and constant law, by which he connects phsenomena 

 which at first sight seem to be quite independent of each other, — 

 V Institute Oct. 5, 1836. 



MELLITIC ACID. 



MM. Liebig and Pelouze, in endeavouring to determine the com- 

 position of mellitic acid, made some experiments on the salt it 

 forms with oxide of silver, which have led them to think that this 

 acid should be considered as a hydracid, their experiments confirm- 

 ing in this respect the views of M. Dulong on oxalic acid. 



Mellitate of silver dried in vacuo over sulphuric acid contains hy- 

 drogen, which it does not lose at a temperature below 356° Fahr. j 

 it is then expelled as water, and the salt changes its colour. This 

 is the case with no other salt of silver, as they are all anhydrous. 

 In this case the formation of water seems to be owing to the reduc- 

 tion of the oxide, and not to a simple volatilization of water existing 

 in the salt. According to known analyses, mellitic acid contains 3 

 equivalents of oxygen. MM. Liebig and Pelouze, however, sup- 

 pose it contains 4 of oxygen and also 1 of hydrogen ; that this hy- 

 drogen enters into the constitution of all the raellitates, except mel- 

 litate of silver, which has been heated to 356°, regarding this last 

 salt as a compound of metallic silver with the radicle of the hy- 

 dracid — Vlnstitut, Oct. 5, 1836. 



METEOROLOGICAL OBSERVATIONS FOR DECEMBER 1836. 



Chistvick, — Dec. 1, Foggy. 2. Rain : stormy. 3. Rain. 4. Overcast : 

 rain at night. 5. Overcast : clear. 6. Cloudy and fine. 7. Stormy showers. 

 8. Showery: clear with lightning at night. 9. Cloudy and cold. 10. Clear 

 and frosty : slightly overcast. 1 1. Slight fog: rain. 12. Rain : stormy at 

 night. 13, 14. Cloudy and cold. 15, 16. Fine. 17. Slight frost ; over- 

 cast. 18, 19. Fine. 20 — 22. Foggy. 23. Cloudy. 24. Clear and cold. 

 25 — 27. Snowing and stormy. 28. Overcast. 29. Snowing. 30. Hazy : 

 snowing : cloudy and cold. 31. Hazy : cloudy and cold. 



The heavy snow storm, which, at London, commenced on the 25th, is 

 perhaps the most remarkable of any recorded at the same period of the 

 season. It appears to have been general, not only over Britain, but also 

 over a great part of Europe. A fall of snow is mentioned as having been 

 experienced at Bilboa in Spain, on the night of the 24th. — R. Thompson. 



Boston.— Dec. 1. Fine. 2. Cloudy. 3, 4. Fine. 5. Rain. 6. Fine. 

 7, 8. Fine : ruin early a.m. 9— 1 1 . Fine. 1 2. Cloudy : rain a.m. 



13 — 15. Fine. 16. Fine: rain early a.m. 17. Fine. 18, l9. Cloudy. 

 20 — 23. Fine. 24. Cloudy : snow r.M. 25. Fine : snow a.m. and p.m. 



26. Snow. 27. Cloudy. 28. Snow. 29. Cloudy. 30. Snow. 31. Cloudy: 

 melted snow. 



N.B. The 24th, 25th and 26th an immense fall of snow, which was 

 drifted in some places ten feet deep. The mail twenty hours behind the 

 usual time. — S. Veall. 



