I did a couple of other measurements of each of these, they came out the same to 2 decimal places. Must get the pipette calibrated again.

Running the numbers we get

5.38 / 4.78 = 1.125

Or near as dammit 1.12 for the density of this heavy water. If it had absorbed much normal water it would be less dense, so I can assume that within the limits of a 10 min experiment on a Tuesday morning before my second cup of Tea, that this heavy water is pretty pure.

#science