SELF-REGISTERING ANEMOMETER AND RAIN-GAUGE. 137 



to the first row of diagrams on Plate VIII. will render this fact very strikingly 

 apparent ; these are all drawn to one scale, so that the comparative motion 

 of the air from each point, for the different years, may be seen at a glance ; 

 they are on precisely the same plan as those I brought before the British 

 Association in 1840*, the difference being that the mileage of each wind 

 is in this case regarded instead of the force. To this mode of making dia- 

 grams of the wind, the title of " Wind Stars" has lately been given by Captain 

 Fitzroy. I had prepared similar diagrams for each month and quarter of 

 the year, but have reserved these until a longer range of averages had been 

 obtained. 



In the second row of diagrams, Plate VIII., the hours during which each 

 wind has lasted are compared, instead of the number of miles ; in these, the 

 resemblance the different years bear to one another is even more striking. 



The average hourly rate at which each wind travels, is shown in the third 

 row of diagrams, Plate VIII.; from this it will be seen that all those winds 

 having a westerly bearing travel very much the fastest : those from the S. to 

 the E. proceed at a much slower rate, while such as come from the North- 

 east average but a little more than one-third the rate of the Westerly winds 

 (for the exact rates see Table III., Column 6). 



With reference to the results obtained from the Rain-registers, the first 

 row of diagrams, Plate IX., gives a comparative view of the amount of rain 

 which accompanied each wind, while the second row exhibits the number of 

 hours it occupied in falling; from these the hourly rate is at once obtained, 

 and the result is shown in the third row of diagrams on the same Plate. In 

 addition to this, the quantity of rain compared with the amount of air that 

 passed over the station has been taken out (see Table III. column 2), and a 

 diagram (see Plate X. fig. 2) is given, showing the mean quantity of rain 

 that falls to every thousand miles of air from each point of the compass. 

 By this it will be observed that the North-Flasterly winds, -which are smallest 

 in amount, bring with them a much larger proportion of rain than those from 

 any other point. 



Table V. — Whole amount of rain that fell between each hour. 

 See Plate X. fig. 1, and Table IV, col. 4. 



