A Meteorological Observatiom^f^'^\^\ 327 



It will be easily understood that the inverse experiments might be 

 made with equal success. The porous vase might be surrounded 

 with hydrogen and filled with air, when the interior pressure would 

 increase instead of diminish. 



Almost all the gases which I have studied furnish the same mani- 

 festations with less energy, and it appeared to me that the pressure 

 always diminished with the gas which filters best, and increased with 

 that which is the worst to filter. These experiments, like all those 

 on the endosmose of liquids, must be explained, as it appears to me, 

 by the theory proposed by M. Magnus, which makes endosmose 

 depend, in the first place, on an unequal power of filtration of the 

 two liquids in presence ; and secondly, on a special force which sets 

 them in motion, — a force which may be an affinity, an electrical 

 action, or even a simple molecular action. — Comptes Rendus, July 28, 

 1856, p. 234. 



METEOROLOGICAL OBSERVATIONS FOR AUG. 1856. 



Chiswick. — August 1, 2. Slight haze : very hot. 3. Hot and sultry. 4. Over- 

 cast : very hot. 5. Cloudless and hot. 6. Cloudy : slight haze : very fine. 7. 

 Clear : hot and sultry. 8. Cloudy : overcast : very fine : rain. 9. Slight rain. 



10. Cloudy and fine. 11. Very fine : cloudy : rain. 12. Cloudy : very fine. 13. 

 Very hot : heavy rain at night. 14. Cloudy and fine : rain. 15. Cloudy and fine. 

 16. Very fine : thunder, lightning and rain at night. 17. Slight rain at half-past 

 eight A.M. : excessively heavy rain commenced, nearly an inch fell in one hour : 

 cloudy at night. 18. Cloudy. 19. Overcast : rain. 20. Foggy : overcast : heavy 

 rain at night. 21. Densely clouded : boisterous, with heavy clouds and showers. 

 22. Partially overcast : cloudy : very fine. 23. Fine. 24. Cloudy and fine. 25. 

 Slight showers. 26. Very fine. 27. Uniformly overcast : very fine. 28. Cloudy 

 and fine : rain. 29. Very fine. 30. Slight fog: very fine. 31. Very fine : rain 

 at night. 



Mean temperature of the month 63°-40 



Mean temperature of Aug. 1855 00-00 i%, 



Mean temperature of Aug. for the last thirty years 61 '97 



Average amount of rain in Aug 2-413 inches. 



Boston. — Aug. 1 — 3. Fine. 4. Cloudy. 5, 6. Fine. 7. Fine : thunder, light- 

 ning and rain a.m. and p.m. 8. Fine. 9. Cloudy : rain a.m. and p.m. 10. Cloudy. 



11, 12. Fine. 13. Cloudy. 14. Cloudy : rain a.m. 15, 16. Fine. 17. Rain 

 A.M. and P.M. 18. Cloudy : rain a.m. and p.m. 19. Cloudy. 20. Cloudy: rain 

 A.M. and P.M. 21. Rain a.m. and p.m. 22. Cloudy : rain a.m. 23. Cloudy. 

 24. Rain. 25. Cloudy. 26. Cloudy: rain p.m. ;\,J^j.,j91oudy: rain a.m. 28. 

 Cloudy : rain A.M. and P.M. 29 — 31. Cloudy. V'^,.. , ,|, 



Sandwich Manse, Orkney. — Aug. 1. Drizzle a.m. : fog p.m. 2. Clear, fine a.m. : 

 clear p.m. 3. Bright a.m. : cloudy p.m. 4. Bright a.m. : clear, fine, aurora p.m. 

 5, 6. Bright a.m. : clear, fine p.m. 7. Bright a.m. : cloudy, fine p.m. 8. Cloudy 

 a.m. and p.m. 9. Cloudy a.m. : cloudy, fine p.m. 10. Bright a.m. : cloudy p.m. 

 11. Drops A.M. : drizzle P.M. 12. Bright a.m. : thunder-showers p.m. 13. Clear 

 a.m. : bright p.m. 14. Bright a.m. : vapour, fine p.m. 15. Damp a.m. : drizzle p.m. 

 16. Damp a.m. : clear p.m. 17 — 22. Cloudy a.m. and p.m. 23. Cloudy a.m.: 

 cloudy, drops P.M. 24. Bright a.m.: cloudy p.m. 25. Rain a.m. : showers p.m. 

 26. Showers a.m. : drizzle, showers p.m. 27. Cloudy a.m. and p.m. 28. Rain 

 a.m. : drops p.m. 29. Showers a.m. : drops p.m. 30. Clear a.m. : cloudy p.m. 

 31. Rain a.m. : clear, aurora p.m. fis^ 



Mean temperature of Aug. for previous twenty -nine years ... 55°-03 r. 



Mean temperature of this month 53-22 ^' 



Mean temperature of Aug. 1855 56-10 ^^^ 



Average quantity of rain in Aug. for previous sixteen years ... 3-01 inches. 



