From G. H. Darwin   8 July 1873

When filled by you the dram measure weighed 281^.92 grains & when empty & moist it weighed 226^.20 gr.

Therefore you have been using 55^.72 gr. as a dram

It should however have been 54^.7 gr   So that you have been using a dram too large by 1 gr. of distilled water

G H. D.

July 8. ’73

The weight of fluid used by you at 2 oz was 865^.5 gr. on one occasion & 866^.5 gr on a second occasion taking the average it was 866 gr. 2 oz: weigh 875 gr.

So that you have been using as 2 ounces an amount of water too small by 9 gr.¹