112 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



In this table the unit of B is one two-hundredth of an 

 inch. 



From this table the following data have been taken: 



Maximum temperature = 74°.o, July 3 



Minimum temperature = 55°.i, June 12 



Maximum range = i8°.9 



Maximum barometer = 5194, June 14 



Minimum barometer = 5145, June 12 



Maximum range = 49. 



During this period of observing, the maximum differ- 

 ence between the dry and the wet bulb thermometers was 

 75°. 5 — 48°.o = 22 . 5. This was on June 29. The 

 minimum was 65 .0 — 56°.o = 9°.o, which occurred 

 June 27. 



Concerning the maximum temperature noted above, 

 74 . o, it should be remarked that this was the first reading 

 of the period, and was taken several minutes before the 

 sun had set. 



Besides the regular thermometers in the air space be- 

 tween the north walls, three other thermometers were sus- 

 pended from the ceiling of the observing room. All three 

 were swung under the observing slit, near the plane of 

 the meridian. One was directly over the instrument, and 

 three or four feet from the ceiling. The other two were 

 hung, one north and one south, about half way between 

 the instrument and the north and south walls respectively, 

 and at such a distance above the floor that the plane of the 

 axis of the instrument and the line of sight of the telescope, 

 pointed at about 83 zenith distance (north and south 

 respectively), would intersect the thermometers near their 

 bulbs. 



Before being thus placed, these thermometers were 

 compared with Green 494, so that their readings could be 

 reduced for comparison with those of the external ther- 

 mometer (Green 494). 



During the course of an evening's observations these 

 three thermometers were read just after reading the regular 

 thermometer. The average difference between the inside 

 and the outside thermometers was found to be the same 



