Prepare the strawberries as for canning. Peel and slice the pineapple, remove the eyes, and cut into small pieces.
Add the water to the sugar in a preserving kettle, and allow it to come to a boil. Drop the pieces of pineapple into the sirup and cook them until they are tender.
To this add the strawberries and cook for 5 or 10 minutes longer.
The conserve should then be sufficiently cooked to put into the jars.
If the juice seems too thin, fill the jars, which should be hot sterilized ones, about three-fourths full of the fruit, and then return the sirup to the heat and boil it until it is the right consistency.
Remove the boiling sirup from the stove, and pour it over the fruit in the jars until they are full.
Allow the conserve to cool, and then seal, first with paraffin and then with metal or paper covers.