... 45' 36 N. Height above sea level, 325 feet. The instruments employed in the observations are Negretti and Zambra, the eminent opticians of Hattod Garden, London, and have been compared with standarn instruments, and the observations have been corrected for index errors, temperature, and for diurnal range, while the hygrometrical deductions have been obtained from Glaisher's Tables. The mean ...