524 C. PIAZZI SMYTH ON THE 



which he knew I was working at in the subsequent spectrum, — steadily on the. 

 collimator's slit, for as long as I could make effective use of it. 



This important assistance so greatly increased my powers for work, as to 

 enable me after all just to accomplish the three spectra, pack up the instrument, 

 and return to Edinburgh within a day of the date required. 



METEOKOLOGICAL APPENDIX TO PAKT I. 



The originals of the following Meteorological observations, so important as a guide to 

 water-gas lines, and their varying manifestations from day to day, though telluric, in the 

 Solar Spectrum, have been kindly handed to me by Col. Knight; and were taken by himself 

 at his Observatory, within a few yards of Kurn Hattin, Harestock, Winchester,— in 

 Latitude = 51° 4' 43"'4 N. 

 Longitude = h 5 m 21 s '53 W. 



Height of cistern of barometer above mean sea-level— 316 feet 7 inches. 

 The daily time of observation being 9 h A.M., and the means referring always to that hour 

 except in the case of self-registering instruments ; whence, 

 in June, Mean Barometric Pressure, reduced to sea-level and Temperature 68°, =30445 inches 



1884. Mean Temperature of Air in shade, = 58°-3 F. 



Mean of Self-registering Maximum Thermometer, .... = 65° - 9 F. 



Mean of Self-registering Minimum Thermometer, .... = 48°4 F. 



Mean Semi-daily Eange of Temperature in shade, . . . . = 8°-9 F. 



Mean Depression of Wet-bulb temperature in shade, . . . = 4°"7 F. 



Water-gas in a cubic foot of Air, computed, .... 



Mean Pielative Humidity (Saturation = 100), computed, . 



Water-gas still required to saturate a cubic foot of Air, computed, 



Total Sunshine, by Eecorder, in a.m. hours, .... =80 hours 45 minutes 



Total Sunshine, by Eecorder, in P.M. hours, . . . . =92 hours 14 minutes 



Wind, Measured mean miles per hour, . . . . . = 6 - 74 



Wind, Direction E. to W. as 3 to 6 ; and S. to N. as 4 to 16, . =N. by W. nearly 



and in July, MeanBarometricPressure,reduced to sea-levelandTemperature68°F., = 30 - 064 inches 



1884. Mean Temperature of Air in shade, = 62°-2 F. 



Mean of Self-registering Maximum Thermometer, . . . = 68° - 6 F. 

 Mean of Self-registering Minimum Thermometer, . . . = 52 0- 5 F. 

 Mean Semi-daily range of Temperature in shade, . = 8 o, F. 



Mean Depression of Wet-bulb Temperature in shade, . . = 4° - 3 F. 



Water-gas in a cubic foot of Air, computed, . . . = 4 - 6 grains 



Mean Eelative Humidity (Saturation = 100), computed, . . =76 - 

 Water-gas still required to saturate a cubic foot of Air, computed, = 16 grains 

 Total Sunshine, by Eecorder, in A.M. hours, . . . =60 hours 38 minutes 



Total Sunshine, by Eecorder, in p.m. hours, . . . =84 hours 37 minutes 

 Wind, Mean measured miles per hour, . . . . = 8 - 24 

 Wind, Direction, E. to W. as 2 to 10 ; and S. to N. as 14 to 3, = S.S.W. nearly.* 



* From observations taken by my friend, Mr Kand Capron, F.R.A.S., at Guildoun, Guildford, 



= 4-0 grains 



= 73-0 



= 1*5 grains 



