16 Meteorological Observations on Parisnath Hill. [No. 1. 



The curve of the real hourly mean temperatures, Fig. 4, a. presents 

 on the 1st and 3rd April some slight inequalities, which must be 

 corrected, in order better to exhibit the real shape of the curve. 

 We know that the ascent from the minimum in the morning to the 

 maximum in the afternoon, must be gradual and continuous, unin- 

 terrupted by irregular and sudden deviations. The corrections will 

 have to be regulated by the turning points of the curve, which it is 

 therefore of importance to fix beforehand. 



In a similar case* the maximum hour of the real mean tempera- 

 tures of the air between the stations has been found, in a greater 

 height, to fall after the maximum hour of the mean temperatures of 

 the stations. 



In the present case the shape of the curves of both days distinctly 

 forbids us to look for the maximum after 2 p. M. On the 1st there 

 is a doubt between 1 and 2 p. m., but on the 3rd the hour of 2 p. m. 

 decisively predominates. The hour of 2 p. m. also preponderates in 

 the hourly means of the stations, and, such being the case, theore- 

 tical reasons, as well as experience, speak strongly against the 

 occurrence of the real maximum of the air between the stations 

 before that hour. In the present instance the height of the stratum 

 of air is so small, that a near coincidence of the hour of its maxi- 

 mum temperature with that of the maximum temperatures of the 

 stations cannot be considered irregular, and we may safely admit 

 the hour of 2 p. M. as that of the maximum temperature in the curve 

 of the real hourly means. 



The hour of the minimum, 7 A. M., which is clearly indicated as 

 such on the 1st and not contradicted on the 4th, was not altered, 

 as there are reasons, which will be mentioned further on, for consi- 

 dering a further slight decrease of the temperature of the air for a 

 sliort time after sunrise, as a not unusual occurrence. The correc- 

 tions were effected graphically, by adopting, wherever the continu- 

 ous line was broken, a mean course between the deviations on either 

 side, supposed to have been caused by the real mean temperatures 

 having been found too high or too low. They are put opposite the 

 respective hours in Col. III. of the table. On the 1st April only 

 the hours 12 and 1 required readjustment, all others having been 

 taken as correct. 



* A. and H. Schlagintweit, k. o. 



