The Areas of the blue, red, & black wedges are each measured from the

centre as the common vertex.

The blue wedges measured from the centre of the circle represent area for

area the deaths from Preventible or Mitigable Zymotic Diseases, the red

wedges measured from the center the deaths from wounds, & the black

wedges measured from the center the deaths from all other causes.

In September 1854, & May 1855, the black area coincides with the red, in

January & February 1856, the blue coincides with the black.

The entire areas may be compared by following the blue, the red & the

black lines enclosing them.