780 STATK BOARD OF AGRICULTURE. 



Cousiderinjr fii'st tables 80 to HO inclusive which contain the daily and 

 monthly maximnra and minimnm and also the averajre monthly ampli- 

 tude, of the different types of soil for the second year during which they 

 were not covered with a layer of sand, it will be seen (1) that during the 

 winter months when the soils wore frozen the fluctuation, or the dif- 

 ference between the maximum and minimum, was practically negligible 

 in all soils and at all three depths. With the exception of a few cases 

 the monthly amplitude was of equal magnitude not only in all the soils 

 but also in all the various depths, and it amounted as a rule to about 

 1°F. During a few days towards the middle of February, however, it 

 amounted to several degrees at the upper 6-inch depth, in some of the 

 soils. 



(2) Immediately upon thawing in the spring the magnitude of fluctu- 

 ntion began to increase. Tt became greatest in the sand and grnvel and 

 slightly smaller in the loam and clay and least in peat. It continued to 

 increase until June when it reached its maximum in all the soils at all 

 three depths. As an average for this month it ran as follows for the 6. 

 12. and 18-inch depths resTiectivelv : gravel 14.63°. 5.78°, 2.52°; sand 

 14.67°, 5.51°. 1.87°: loam 11.58°, 1.71°. 0.37°; clay 11.67°. 2.50°. 0.58°; 

 and. peat 4.10°. 0.86°. 0.80°F. At certain individual days during this 

 month it ran as high as 20°F in the case of sand and gravel and only 

 about 5°F in peat, at the 6-inch depth. From June on it began to de- 

 crease in every soil and at every depth and continued to diminish until 

 the soils froze again. 



(3) The soils which attained the lowest minimum temperature also 

 attained the highest maximum and they arrange in the following descend- 

 ing order: sand or gravel, loam, clay, and peat. The difference, however, 

 between the lowest minimum temperature of the different soils was not 

 vprv large, the highest average variation for any month was only about 

 8°F. The difference, however, between the maximum of these soils was 

 quite anpreciable and especially betwen the sand or gravel and neat in 

 which it amounted in some months, after complete thawing had taken 

 place, to about 0°F. In other words the magnitude of the minimum 

 temperature attained bv the diverse classes of soils was about the same 

 or very close, while that of the maximum varied somewhat and especially 

 between the sand or gravel and peat. 



The close equality of the minimum temperature in the diverse classes 

 of soil, therefore, contradicts the common belief that the light soils 

 become greatly colder or reach a far lower temperature during the night 

 than the heavier soils and especially peat, while the rather marked dif- 

 ference in the maximum temperature ffoes to indicate that it is mainly 

 this which is responsible for the variation in the average temperature ob- 

 sen^ed in the various tvnes of soil durino; the soring and summer months. 



The data on the dailv nnd monthly maximum and minimum and 

 monthly range for the third year are contained in Tables 51 to 62 in- 

 clusive. It should be remembered that the soils during this year were 

 covered with a thin layer of sand. 



The order and magnitude of the fluctuation of the different soils dur- 

 ing the third year agree with those of the second vear lust discussed, 

 but the ordpv an*! map-uitude of the minimum and maximum ^disafrree 

 most markedly. Indeed, the latter were just reversed in the third year. 

 The magnitude of the maximum became more equal in the various soils 



