Well, Obviously

TO PRESERVE PINE-APPLES

Make a thick, rich syrup; slice the pine-apple after paring it, and boil in the syrup until perfectly clear.

TO PRESERVE PINE-APPLE WITHOUT COOKING

Pare and slice your pine-apple.  Make a thick, rich syrup, and boil it till quite clear.  Clarify your syrup nicely.

Home Cookery; A Collection of Tried Receipts, both Foreign and Domestic, by Mrs. J. Chadwick, 1853.