Note 85 — I. Preservation of Objects composed of Inorganic Substances.

It has been found that the formation of this layer of slime may be avoided by the use of tubs which are lined with sheet zinc. The addition of 10-20 cubic centimetres of formalin [40% solution of formaldehyde] to every hundred gallons of water also prevents or restrains the formation of slime. It is not necessary to add formalin each time the water is changed.