Its symbolic expression, to a numerical factor pres, is (Hbc) (Hbd) (Hcd) (**bcd**), and it is clearly of degree 6.

The summit C of the branch **BCD** occurs at a percentage exactly corresponding to the formula Hg 2 T1.

Then ABF = angle of elevation; EFB =quadrant angle; **BCD**=angle of sight; EBF=ABF - ABE; and since ABE = **BCD**, it also equals ABF - **BCD**.

Also, let angle ABC =7r - 0, angle **BCD** =ir - 4, angle between BC and AD = G.

**BCD** c is the solubility curve of phenol in water.

7 gives the freezing-point curve of mercury and thallium; here A and E are the melting-points of pure mercury and pure thallium, and the branches AB and ED do not cut each other, but cut an intermediate rounded branch **BCD**.