before sunrise. When the line on which this 18° is measured is shortest then the twilight will be the shortest, and vice versa. This causes the shortest twilights to occur in the winter months in northern latitudes, and longest in summer. By an examination of the chart we find the measure of twilight, darkness and daylight of the 24 hours to be: Jan. 1, Length of day Sh. 54m. June 21, Length of day. .15h. 34m. Length of twilight. .1h. 45m. Length of twilight. 2n. 30m. The remainder of the space will more than make the 24 hours, which is due to refraction of light, which causes an increase in the apparent length of the day, as also of duration of the twilights. This apparent error is greatest in the winter months, as the Sun then shines through a denser and deeper atmospheric envelope. THE HORIZON AT SEA LEVEL. Distances of objects visible at varying elevations from one foot to one thou *DISTANCE FROM THE EARTH IN LIGHT YEARS OF CERTAIN *EXPLANATION.-The term "Light Year" is the time required for light to travel from these bodies to the earth. Their actual distance, in miles, being too great for use or comprehension, the distance, in miles, may be found by multiplying the velocity of light (183,000 miles per second) by the number of seconds in a year. and that product by the light years. Thus: Alpha Centauri 3.6X183,000X365X24X 60X60 miles distant. Cal. for Wash, D. O., Calendar for Charleston, 8. So. New York, Conn., R. I., Pa., N. J. Northern part of Ohio, Ind., and Ill., 8o. Iowa, Neb., N. Col., Utah, Nev., Cal. Moon Bun Bun rises H. W. Sun Sun rises. sets. and N. Y. rises. sets. sets. sets. ton. H.M.S.H. MH. MH. MH. MH. MH. MH. MH. MH. MH. M│H.MH. MH. MH. MH. MH. MH. MH.M 1Tu 12 3 24 2 2W 7 37 4 31 6 19 7 30 4 38 6 32 ev 25 7 25 4 43 6 37 8 32 7 19 449 6 41 7 3 5 5 6 54 8 43 12 3 53 7 37 4 32 7 19 7 30 4 39 7 30 1 4 7 25 4 44 7 34 9 5 7 19 4 50 7 38 7 8 5 6 7 49 9 20 H.M.S.H. MH. MH. M H.MH.MH.MH.M H.MH.MH.MH.M H.MH.MH.M H.MH.MH.MH.M 12 13 41 719 5 9 8 25 7 14 5 14 8 29 12 13 49 6 55 5 33 8 36 9 38 32 1Fr 1 18 7 10 5 18 8 31 9 25 7 65 22 8 32 33 2 Sa 84 8S 35 4 Mo 7 18 5 11 9 34 7 18 5 15 9 35 2 2 7 9 5 19 9 35 10 5 7 5 5 23 9 35 6 54 5 34 9 37 10 19 12 13 56 7 16 5 12 10 43 7 12 5 17 10 41 2 48 7 8 5 20 10 41 10 48 7 45 24 10 40 6 54 5 35 10 38 11 4 12 14 2 7 15 5 13 11 52 7 11 5 1811 48 3 37 7 7 5 22 11 46 11 35 7 3 5 25 11 44 6 53 5 36 11 39 11 52) 5 19 mo. 4 32 7 6 5 23 mo. ev 27 7 2 5 26 mo. 6 52 5 37 mo. ev 44 12 14 13 7 13 5 16 1 '5 7 8 5 20 12 57 5 29 7 5 5 24 12.55 1 28 7 1 5 27 12 52 6 51 5 37 12 43 1 46 88 7 Th.. 12 14 17 7 11 5 18 2 20 7 7 5 22 2 9 6 33 7 4 5 25 2 6 2 44 7 0 5 28 2 2 6 50 5 38 1 512 54 89 8 Fr 40 9 Sa 41/10 S 42 11 Mo 43 12 Tu 44 18 W 45 14 Th .... 12 14 20 7 10 5 19 3 35 7 6 5 23 3 19 7 87 7 8 5 26 3 14 4 12 6 59 5 30 3 10 6 50 5 39 2 57 4 7 12 14 23 7 9 5 20 4 41 7 4 5 25 4 26 8 42 7 1 5 28 4 22 5 28 6 58 5 31 4 17 6 49 5 40 4 2 5 13 12 14 24 7 7 5 22 5 42 7 8 5 26 5 27 9 42 70 5 29 5 23 6 31 6 57 5 32 5 18 6 48 5 41 5 3 6 14 5 33 6 13 6 47 5 42 6 0 7 8 12 14 25 7 4 5 25 sets 7 0 5 29 sets 11 30 6 58 5 31 sets 8 15 6 55 5 34 sets 6 46 5 43 sets 7 57 12 14 25 7 3 5 26 6 38 6 59 5 30 6 45 mo. 6 56.5 32 6 47 9 3 6 54 5 35 6 49 6 45 5 44 6 56 8 45 12 14 24 7 1 5 27 7 50 6 58 5 31 7 53 12 20 6 55 5 34 7 54 9 49 6 52 5 36 56 6 44 5 45 8 0 9 34 12 14 21 ... 7 0 5 29 8 59 6 56 5 32 9 0 1 7 6 54 5 35 9 0 10 34 6 51 5 38 9 0 6 43 5 46 9 1 10 20 211 20 6 50 5 39 10 2 6 42 5 46 9 59 11 8 12 14 15 6 57 5 32 11 10 6 53 5 35 11 5 2 401 6 51 5 37 11 3 mo. 6 49 5 40 11 2 6 41 5 47 10 56 11 59 49 18 Mo 12 14 10 6 55) 5 33) mo. 652 5 36 mo. 3 28 650 5 38 mo. 12 7 6 47 5 41 mo. 6 40 5 48 11 52 mo. 6 54 5 34 12 14 6 51 5 37 12 6 4 17 6 48 5 40 12 812 57 6 46 5 42 12 1 6 39 5 49 mo. 12 50, 61 20 W. 12 14 0 6 52 5 36 1 16 6 49 5 39 1 5 5 8 6 47 5 41 1 2 152 6 45 5 43 12 58 6 28 5 50 12 47 142 52 21 Th 12 13 53 6 50 5 37 2 15 6 48 5 40 2 3 6 0 6 46 5 42 1 58 2 51 6 43 5 44 1 54 6 37 5 51 1 41 237 58 22 Fr. 12 13 46 6 49 5 39 3 11 8 46 5 41 2 57 653 6 44 5 43 2 53 3 48 6 42 5 45 2 48 6 36 5 52 2 34 3 30. 54 23 Sa 12 13 38 6 47 5 40 4 2 6 45 5 42 3 48 7 46 6 43 5 44 3 431 4 44 6 41 5 46 3 38 6 35 5 52 3 23 4 20 55 24 S 12 13 90 6 45 5 41 4 52 6 43 5 44 4 38 S 35 6 41 5 45.4 33.5 26 6 39 5 47 4 28 6 84 5 53 4 13 5 7 56 25 Mo 12 13 21 6 44 5 43 5 85 6 42 5 45 5 22 9 22 6 40 5 47 5 17 6 5 6 38 5 491 5 13 6 32 5 54 4 591 5 52 57/26 Tu 68 27 W 59 28 Th.. 12 13 11 6 42 5 44 6 13 6 40 5 46 6 1 10 7 6 38 5 48 5 57 6 43 6 37 5 50 5 53 6 31 5 55 5 41 6 34 12 18 1 6 41 5 45 rises 6 38 5 47 rises 10 50 6 36 5 49 rises 7 18 6 35 5 51 rises 6 30 5 56 rises 7 15 12 12 50 6 89 5 47 6 14 6 37 5 49 6 19 11 31 6 35 550 6 21 7 52 6 34 5 52 6 22 6 29 5 571 6 28 7 55 H.M.S. H. MH. MH. MH. MH. MH. MH. MH. MH. MH. MH. MH. Calendar for Mo Calendar for Boston, Mann, Moon MH. MH. MH. MIH. MIH. MH. M Moon Sun Sun rises rises. sets. and Sun Sun rises. sets. and sets. to n. 60 1Fr 12 12 39 6 37 5 48 7 23 6 36] 5 51 7 25 ev 12 6 85 5 53 7 26 8 29 6 33 554 7 27 6 28 5 59 7 29 8 35 |