356 On certain Points in Meteorology and Magnetism, 



I consider worth communicating to you. As long as I can re- 

 member, the equinoctial gales came from the westward, until 

 the westward variation of the magnet ceased to proceed, and 

 it began to retrograde towards the north, when the gales have 

 come from the eastward. Easterly gales have this year pre- 

 ceded the equinoxes, and at this moment it is blowing hard 

 from the east at the place whence I write. This leads me to 

 think that it would be of importance for those who have the 

 charge of meteorological registers, to examine them in refer- 

 ence to changes in magnetic variation during past times, as 

 far back as registers go ; and to note whether any remarkable 

 changes in climate have taken place ; and more particularly 

 to ascertain whether the fact respecting the change in the di- 

 rection of the equinoctial gales has been universal in Great 

 Britain, or confined to the northern parts of the island. Should 

 it be found that there is a connexion between atmospheric 

 phenomena and terrestrial magnetism, and that the move- 

 ments of the magnetic meridian are accompanied by change 

 in the direction of periodic winds, we may come at length to 

 ascertain some laws by which nature is governed hitherto 

 unknown to us. 



I have also observed that the east wind, which has hereto- 

 fore been remarked as the driest, has of late come to us much 

 charged with moisture. 



I beg leave to take this opportunity of remarking, that I con- 

 ceive no dependence can be placed on the thermometric ob- 

 servations made in the garden of the Horticultural Society. 

 It is some time since I pointed out to Professor Lindley the 

 defects of the apparatus. Instead of the thermometer being 

 placed in the shade of a wall, it is exposed near the ground 

 under a wooden roof which absorbs the direct rays of the sun, 

 and radiates heat to the instruments. Thus the indications 

 are too high. 



As it is of importance that the instruments used in meteoro- 

 logical observatories should all agree exactly ; and as it is known 

 that even those constructed by the same maker do not always 

 agree with one another, all the instruments in Europe should 

 be compared. Indeed, one maker should be appointed to 

 construct every instrument used in observatories, so that all 

 may be made to agree with a standard. 



I am, Gentlemen, yours, &c. 

 Coul, Sept. 22, 1835. G. S. MACKENZIE. 



