Cadmium. Chlorine. 64.27 per cent. 35.61 per cent. These proportions are nearly those of a compound having the composition Cd₄Cl₇, in which the calculated percentages are: Cadmium. Chlorine. 64.34 35.66 (Foot note). In the paper in the American Chemical Journal XII, 488, which records this work the analyses and percentages were calculated on the basis of the atomic weight of cadmium = 111.7. Although my work since this date has shown that 112.07 is the true value, yet I think it preferable to use the old number here since the changes to be introduced would be very slight and the same results are thereby kept uniform in the two publications. In order to determine whether the close approximation to definite atomic proportions might not be accidental, the material was reheated with an excess of the metal for twenty hours. The product was analyzed. Amount of chloride used 1.45970 gr. ” ” cadmium found .93904 ” ” ” chlorine ” .52329 ” Cadmium. Chlorine. 64.33 per cent. 35.85 per cent. A second preparation of the substance was made in all respects like the first. Two analyses were made. First Analysis: Amount of chloride used .61010 gr. ” ” cadmium found .39235 ” ” ” chlorine ” .21725 ” Cadmium. Chlorine. 64.31 per cent. 35.61 per cent. Second Analysis: Amount of chloride used .20616 gr. ” ” cadmium found .13266 ” ” ” chlorine ” .07352 ” Cadmium. Chlorine. 64.35 per cent. 35.66 per cent. A third preparation was made like the first and second and analyzed. Analysis: Amount of chloride used .2832 gr. ” ” cadmium found .18244 ” ” ” chlorine ” .10123 ” Cadmium. Chlorine. 64.42 per cent. 35.74 per cent. When the new substance is heated it fuses to a red liquid and then breaks up into metal and the chloride of cadmium. Its reactions are in general those of a strong reducing agent. Treated with nitric acid, oxides of nitrogen are liberated. With dilute hydrochloric, sulphuric and acetic acids it gives free hydrogen. In the presence of dilute acids it reduces mercuric to mercurous chloride, or to metallic mercury. Three determinations of the reducing power of the substance were made with a freshly prepared specimen, by dissolving weighed portions in hydrochloric acid and measuring the hydrogen liberated. The following results were obtained: Hydrogen found. Hydrogen calculated for Cd₄Cl₇. 1ˢᵗ determination 15.67 c.c. 15.65 c.c. 2ⁿᵈ ” 11.80 c.c. 11.82 c.c. 3ʳᵈ ” 23.00 c.c. 23.03 c.c.