







Temperature of the Air. 









263 



TABLE II. — Means of the Maximum and Minimum Temperature of the Air for each Day 



in 1843, 



as 









deduced from the Self-Regisi 



jcring Thermometers. 









Uvil 

 Jay. 



January. 



February. 



March. 



April. 



May. 



June. 



July. 



August. 



September. 



October. 



November. 



December. 





o 



o 



o 



o 



o 



o 



O 







o 







o 



c 



1 



330 



4M 



31-8 



51-5 



46-2 



45-7 



55-8 



56-4 



62-1 



59-7 



35-1 



34-6 



2 



320 



390 



32-6 



52-5 



44-8 



56 



3 



57-9 



59 



3 



64-9 



53-9 



37-4 



36-7 



3 



32-8 



32-3 



33-9 



50-2 



48-3 



46 



2 



61-3 



59 



7 



64-3 



48-5 



36-6 



44-2 



4 



390? 



29-9 



30-7 



44-4 



50-1 



45 



3 



56-7 



59 







56-4 



56-4 



44-3 



48-5 



5 



35-5 



321 



36-7 



45-8 



46-1 



43 



3 



59-5 



56 



1 



52-7 



58-6 



38-9 



49-4 



6 



37-5 



33-0 



42-4 



44-7 



47-2 



46 



8 



59-8 



55 



5 



61:6 



58-7 



43-1 



42-3 



7 



37-5 



38-2 



40-5 



45-8 



49-3 



52 



2 



56-7 



54 



6 



56-2 



55-9 



44-6 



48-1 



8 



31-5 



40-6 



32-6 



41-9 



45-3 



54 



2 



57-0 



63 



2 



58-7 



48-9 



37-6 



45-9 



9 



31-9 





34-5 



39-1 



47-1 



53 







58^2 



60 



8 



62-0 



44-4 



33-1 



45-2 



10 



35-3 



34-7 



38-1 



35-1 



44-4 



55 



8 



58-9 



54 



5 



58-7 



44-8 



37-1 



44-4 



11 



33-2 



35-5 



41-7 



35-7 



48-4 



51 



9 



59-7 



57 







62-6 



40-5 



43-0 



47-2 



12 



261 



37-6 



47-2 



350 



47-8 



50 



6 



56-3 



59 



6 



64-3 



41-7 



38-2 



44-9 



13 



29-2 



32-9 



40-0 



34-2 



54-0 



. 47 



6 



59-3 



61 



3 



55-4 



36-8 



42-8 



46-8 



14 



34-8 



26-9 



37-8 



453 



54-6 



52 







57-8 



57 







51-6 



39-4 



35-8 



47- 1 



15 





23-3 



38-3 



50-5 



45-8 



56 



2 



60-0 



56 



5 



6M 



34-8 



371 



50-7 



16 





26-7 



37-3 



50-5 



45-2 



54 







59-3 



63 



4 



59-7 



341 



37-0 



37-8 



17 



37-2 



26-6 



44-3 



52-1 



44-7 



51 



9 



55-2 



66 







58-8 



35-6 



43-7 



43-8 



18 



43-2 



21-6 



51-5 



49-0 



44-3 



51 



8 



58-4 



65 



1 



57-3 



35-2 



37-1 



42-2 



19 



44-3 



28-0 



46-9 



55-5 



40-9 



48 



9 



54-1 



65 



4 



51-8 



33-3 



38-0 



44-0 



20 



43-2 



33-6 



44-7 



'46-4 



49-0 



56 



7 



51-0 



58 



2 



57-7 



43-3 



40-5 



45-2 



21 



35-1 



34-3 



47-8 



'50-5 



45-1 



57 



8 



55-8 



52 



2 



61-0 



48-8 



43-5 



42-2 



22 



35-7 



360 



50-7 



48-9 



45-3 



56 



3 



54-9 



56 



6 



54-0 



48-4 



42-8 



45-0 



23 



40-0 



36-3 



50-3 



45-1 



46-2 



59 







51-7 



51 



3 



550 



49-3 



33-9 



49-1 



24 



45-0 



37-3 



40-6 



44-3 



47-7 



53 



1 



511 



53 



2 



57-1 



45-9 



31-9 



52-2 



25 



45-3 



35-7 



43-9 



45-8 



47-8 



51 



6 



52-0 



56 



9 



48-3 



39-2 



324 



48-1 



26 



45-3 



360 



400 



42-9 



511 



53 



7 



60-6 



56 







46-5 



37-1 



39-5 



48-0 



27 



49-0 



35-9 



34-1 



44-8 



51-7 



48 



7 



58-3 



53 



4 



44-3 



34-3 



49-4 



44-0 



28 



47-5 



36-0 



38-2 



46-4 



46-0 



49 



6 



57-9 



54 



6 



44-7 



41-9 



48-9 



43-7 



29 



48-0 





35-9 



43-7 



43-1 



51 



9 



59-0 



56 



4 



42-4 



41-7 



45-8 



460 



30 



47-0 





38-5 



49-2 



47-3 



53 



9 



57-6 



52 



5 



55-5 



321 



39-2 



450 



31 



46-5 





50-5 





45-3 





59-2 



59 



6 





36-2 





44-6 



[ean 



38-7 



33-4 



40-5 



45-6 



47-1 



51-9 



571 



57-8 



56-2 



43-9 



39-6 



451 



Annual Variation of Temperature. — The mean temperature is least for the month of February and greatest 

 for the month of August ; the means for April, May, and December differ little from the mean for the year. 

 The monthly means differ slightly in Tables I. and II. ; one cause of this difference will evidently be found in 

 the means for Sundays, included in Table II. ; when these means are deleted, the monthly means from the 

 self-registering thermometers are as follow : — 



Jan. 

 39°-0 



Feb. 



33°-4 



March. 



40°-2 



April. 



45°-3 



May. 



46°-9 



June. 



52°1 



July. 



57°- 1 



August. 



57°-9 



Sept. 



55°-7 



Oct. 

 43°-4 



Nov. 



3 9° 8 



Dec. 

 44°-9 



These quantities differ from the means, Table I., from the observations of the dry bulb thermometer by 



Jan, 



+ 0'-3 



Feb. 

 + 0°-4 



Alarch. 



+ l°-2 



April. 



+ 0°-7 



ilay. 

 + 0°-4 



June. 



+ 0°-l 



July. 



+ 0°-3 



August. 



+ 0°-6 



Sept. 

 + 0^-5 



Oct. 



Nov. 



+ 0°-2 



Dec. 



-0°-3 



Tliese differences evidently have a law, the amount being greatest near the equinoxes and least near the solstices.* 



* These differences and their variations are probably due to three causes ; first, difference of exposure of the register and dry 

 bulb thermometers ; second, difference in the form of the diurnal curve for the various months ; third, less conducting power of the 

 spirit of wine of the minimum thermometer than of the mercury of the maximum. From the last, the registered minimum will, in 

 general, be higher than the true minimum, and so much the more when the change of temperature is most rapid, or when the diurnal 

 range is greatest, namely, near the Equinoxes. See Table 111. 



