【明報專訊】Why are rugby balls oval? In the 1820s, rugby balls were made with pig bladders (膀胱) and hand-stitched leather casings, so they took after the shape of a pig bladder. The shape of a rugby ball was not as distinctive as it is now. Rugby balls varied in size because pig bladders were not of the same size. Modern rugby balls are made with latex bladder (球膽) and casings of natural rubber or synthetic materials stitched with polyester threads.

■Glossary

oval (adj) 橢圓形的

distinctive (adj) 特殊的

latex (n) 乳膠

[Smarties' Power English Vol 183]