APRIL. Illuminating Power in Amount of Impurity. Standard Sperm Candles. Sulphuretted Ammonia per 100 feet, Sulphur Hydrogen. grains. per 100 feet, grains. 1 22.1 None None 17.0 2 23.0 „ „ 13.7 3 Not received 4 22.1 „ 0.4 14.2 6 Not received 7 21.7 „ 2.4 16.8 8 21.5 „ 0.6 17.8 9 22.5 „ 1.2 16.9 10 22.2 „ ... 17.2 11 22.3 „ None 17.2 13 22.7 „ 0.4 17.3 14 21.0 „ 0.4 17.3 15 21.0 „ 1.4 17.1 16 22.9 „ 0.7 17.4 17 21.6 „ 0.4 19.0 18 21.2 „ 0.2 17.9 20 22.2 „ 0.0 19.5 21 Not received 22 22.5 „ 0.2 9.5 23 22.5 „ 1.4 18.7 24 22.2 „ 0.6 18.1 25 23.0 „ 0.4 18.2 27 22 2 „ 0.0 18.0 28 22.0 „ 0.0 18.1 29 21.2 „ 1.0 15.4 30 Not received Mean 22.04 „ 0.56 17.37