Sentence:  The new ounces would be all alike, representing 25 Gm. or CC., and would be from one-eighth to one-fifth less than the customary ounces. The <WSD>metric ounce</WSD>, 25.0; one fifth less than 1 apoth. ounce, 31.0. The <WSD>metric ounce</WSD>, 25.0, one-sixth less than 1 av. ounce, 28.35. 
Meaning of the word marked with <WSD> tags:  25 grams.