182 Mr. Hinds on Climate in eormemon 



for the sun's rising a little to the south of true east. They 

 will act but feebly, both from the cool air they have to tra- 

 verse, and from the very trifling elevation of the sun, this 

 latter circumstance causing them to arrive at a very unfa- 

 vourable angle. The sun gradually reaches the southern side, 

 and continues to ascend in its course. The surface becomes 

 warmed, heat is imparted to the atmosphere, and they con- 

 tinue to receive warmth till some time after midday. The 

 eastern side, however, is momentarily less exposed, and those 

 it has received have been only the cooler rays of the morning, 

 whilst the west is gradually becoming bared to the sun, after 

 it has attained its meridian height and power, and the sur- 

 rounding objects are all well warmed. Hence we perceive 

 the advantage of a southern aspect in the northern hemisphere, 

 and the superiority of a west over an east. We have sup- 

 posed the sides of the mountain to have an inclination of 45° ; 

 if the meridian elevation of the sun only attains 30°, we shall 

 have its rays impinging at an angle of 75°, and one capable 

 of imparting very considerable warmth. By substituting 

 any known mountain, and converting our plane sides into the 

 customary irregularities and depressions, valleys and ridges, 

 the great advantages of aspect will be more manifest, espe- 

 cially after watching the daily passage of the sun over it, and 

 gaining an acquaintance with the vegetable productions* 



Were it not for the atmosphere, the temperature through- 

 out the day would follow the different dispositions of the sun 

 with regularity. Instead, however, the early sun gives out 

 very little sensible warmth, its real heat being absorbed by 

 the atmosphere after its reflection from the surface of the 

 earth. Even at midday, when it might be supposed that the 

 sun was diffusing most heat, the temperature of the air has 

 not reached its maximum. The time of this varies with the 

 latitude between the hours of 1 and 3 p.m. In the afternoon, 

 when the air is thoroughly warmed, and the sun approaches 

 the western skies, the warmest portion of the day has arrived, 

 and the atmosphere retaining the heat with some tenacity, the 

 subsequent depression of temperature takes place slowly. Every 

 one must at times have felt the power of the declining sun's rays 

 through a heated atmosphere when they fall on the uncovered 

 parts of the body. This different diffusion of apparent heat, 

 at periods when the sun holds similar situations with regard 

 to the earth, has its effect on aspect, and bestows some supe- 

 riority on a position exposed to the afternoon's sun; thus 

 somewhere between the south and west points will be found 

 preferable ; the mean, south-west, is perhaps the best ; in 

 low latitudes approaching a little to the south, and in high 



