32 
POPULAR SCIENCE REVIEW. 
in 1864, when compared with the horizontal parallax, assign 
to Mars a diameter scarcely exceeding the earth’s radius ; ethers 
give a diameter greater ; others, in 1865, give a diame- 
ter less than the earth’s radius ; some, in 1866, give a dia- 
meter equal to this dimension; others a diameter exceeding it 
by Jq, others by others by \ ; and, finally, others by that 
is, by 1,150 miles. 
