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Webster 1913 Edition

Adj.

Containing one part of four; in the ratio of one to four;

as,

subquadruple

proportion

Bp. Wilkins.

Adj.

[sub and quadruple.] Containing one part of four; as subquadruple proportion.

subquadruple ‎(not comparable)

Containing one part of four; in the ratio of one to four.
- Bishop Wilkins
  As one of these under pulleys abates half of that heaviness of the weight, and causes the power to be in a subduple proportion; so two of them abate half of that which remains, and cause a subquadruple proportion, three a sextuple, four a suboctuple.