[Footnote 11: Wild Sports or the West.]
[Footnote 12: L’Union Medicale—name
withheld by request of the
[Footnote 13: London Lancet.]
Though the pathological conditions of hydrophobia and serpent poisoning are by no means parallel, the rationale of the methods employed in opening the emunctories of the skin are the same; and were it not for its powerful protracting effect and depressing action upon the heart, we might perhaps secure valuable aid from jaborandi (pilocarpus), since it stimulates profusely all the secretions; as it is, more is to be hoped for in the former disorder than in the latter. It would be desirable also to know what influence the Turkish bath might exert, and it would seem worthy at least of trial.
* * * * *
TO FIND THE TIME OF TWILIGHT.
To the Editor of the Scientific American:
Given latitude N. 40 deg. 51’, declination N. 20 deg. 25’, sun 18 deg. below the horizon. To find the time of twilight at that place. In the accompanying diagram, E Q = equinoctial, D D = parallel of declination, Z S N a vertical circle, H O = the horizon, P = North pole, Z = zenith, and S = the sun, 18 deg. below the horizon, H O, measured on a vertical circle. It is seen that we have here given us the three sides of a spherical triangle, viz., the co-latitude 49 deg. 9’, the co declination 69 deg. 35’, and the zenith distance 108 deg., with which to compute the angle Z P S. This angle is found to be 139 deg. 16’ 5.6”. Dividing this by 15 we have 9 h. 16 m. 24.4 s., from noon to the beginning or termination of twilight. Now, in the given latitude and declination, the sun’s center coincides with the horizon at sunset (allowance being made for refraction), at 7 h. 18 m. 29.3 s. from apparent noon. Then if we subtract 7 h. 18 m. 29.3 s. from 9 h. 16 m. 24.4 s., we shall have 1 h. 57 m. 55.1 s. as the duration of twilight. But the real time of sunset must be computed when the sun has descended about 50’ below the horizon, at which point the sun’s upper limb coincides with the line, H O, of the horizon. This takes place 7 h. 16 m. 30.8 s. mean time. It is hoped the above will be a sufficient answer to L.N. (See SCIENTIFIC AMERICAN of Dec. 1, 1883, p. 346.)