II. A Letter from Mr. Henry Baker, F. R. S. to the President, containing an extract of a letter from Mr. William Arderon, F. R. S. to Mr. Baker, giving an accent of the present condition of the Roman camp at Castor in Norfolk, with a plan of it; and also a representation of an halo or mock-sun observed by the same gentleman July 11, 1749.

Sir, I Take the Liberty to lay before you an Account lately sent me by my ingenious Correspondent Mr. William Arderon , F. R. S. of the present Condition of the Roman Camp at Castor , in the Country of Norfolk