1909] BY MEANS OF KITES AND BALLOONS. 21 



Too careful attention cannot be given to the condition of the reel 

 preparatory to making a flight, and in general all apparatus must be 

 well looked to. Failure in any one of the many details to be 

 attended to at this time and during the flight is almost certain to 

 result in somfe catastrophe. The field work has, for this reason, all 

 the interest of our best college games and the man who is not 

 equipped physically and mentally to enjoy such games will hardly 

 enjoy or make a success of flying kites and balloons. The fact that 

 for the past eighteen months no day (Sundays excepted) has passed 

 in which one or more records of upper air conditions above Mt. 

 Weather were not obtained speaks well for the spirit and efficiency 

 of the men engaged in this work at that observatory. 



The power plant at present in use is equipped with a 35 H.P. 

 double cylinder gasoline engine, a 25 KW. dynamo, and an electro- 

 lyzer by means of which water is separated into oxygen and hydro- 

 gen, the latter for use in the captive balloons, and a gas compressor 

 which may be used to compress hydrogen for shipment or to make 

 liquid air with which to get sufficiently low temperatures to test 

 sounding balloon instruments. A new combination steam power and 

 heating plant is in process of building. 



The computation of altitudes from the pressure trace of the 

 meteorograph record by Laplace's formula and the evaluation of 

 the other elements at these altitudes is another matter altogether and 

 yet not devoid of interest. From five or six up to twenty or twenty- 

 five levels are computed in each trace, i. e., enough to show all pecu- 

 liarities or changes in the temperature gradient or air currents, alti- 

 tudes of clouds passed through, depth of cloud and fog layers and 

 the highest points reached. From these data the temperature grad- 

 ient, i. e., the change of temperature with altitude, usually expressed 

 in degrees centigrade per 100 meters, is plotted for each day and the 

 upper air isotherms continuously charted. The whole, with more 

 or less comment, is published quarterly in the Bulletin of the Mt. 

 Weather Observatory, A study which has for its purpose the sum- 

 marizing of the first year's data is still in progress. Valley stations 

 are maintained on either side of the mountain. At these, data are 

 collected for comparison with the surface readings obtained on Mt. 

 Weather, 1,000 feet above them. 



