250 MR. G. V. VERNON ON TEMPERATURE AT OLD TRAFFORD. 



XVI. On the Mean Weekly Temperature at Old Tr afford, 

 Manchester, for the Seventeen Years 1850 to 1866. 

 By G. V. Vernon, F.R.A.S., F.M.S. 



Head before the Physical and Mathematical Section, January 3rd, 1867. 



As I am not aware that there have been any carefully 

 deduced values of the mean temperature of this neighbour- 

 hood, perhaps the data accompanying this paper may serve 

 until such time as a more extended series can be obtained. 

 I may state that the thermometers used have all been 

 standard ones compared at Greenwich, and all the observa- 

 tions have been reduced to that standard. The thermo- 

 meters are placed upon a stand 4 feet from the ground, 

 and carefully protected from radiation and other dis- 

 turbing influences. 



Unavoidable omissions in my register I have been 

 enabled to supply by the kindness of my friend Mr. John 

 Curtis, F.M.S., whose thermometers are placed similarly 

 to my own, and within a very short distance from my sta- 

 tion. The mean values have generally been determined 

 from the readings of the maximum and minimum ther- 

 mometers in the shade, combined with readings of a stan- 

 dard thermometer, read once a day, these observations 

 being all made at 8 a.m. : in reducing them, Mr. Glaisher's 

 corrections for diurnal range have invariably been applied. 

 Whilst upon this subject I would like to suggest the great 

 desirability of having these corrections deduced from a 

 much longer series of observations ; for although on the 

 whole I find them to agree pretty closely, yet at times 

 great dififerences exist, especially in comparing the mean 

 temperature deduced from maximum and minimum read- 

 ings with those of a standard thermometer read at certain 

 fixed hours. 



