More on the benefits of this animal

IF anyone cares to consult Dioscorides, he will find that seals’ gall has many uses. ¹ These creatures are so spirited that if they hear the roar of thunder and see flashes of lightning, they climb delightedly on to flat slabs of rock, just like frogs, which are overjoyed should it threaten to pour with rain. ² Whenever sailors from Bothnia, or northern lands generally, purpose to set sail towards Germany in the bitterest winter weather, they coat their ships’ timbers with oil from this animal, so that the water does not freeze round the keels and cause their vessels to founder. ³ Again this oil, known in the vernacular as seeltraan, is excellent for rubbing on the different hides and skins called shammy leather, from which supple boots are made. Thus we may see how in Prussia the leather, treated with this oil, is prepared by means of water-driven wheels to be sold in Flanders, and eventually exported to Italy, France, and Germany. ⁴ Unless oxhides too are rubbed with seal or whale oil, they are inadequate for the manufacture of leggings worn by travellers when it rains, since this keeps out all the damp and makes them last for ages. ⁵ If you rub such grease over shoes or leggings, or on the halters by which horses are tied to their stalls, the mice do not gnaw them away, as they do if you smear them with fat from cattle or rams. And, of course, leather treated in this way has the virtue of never being touched by lightning, wherever you may fasten it. ⁶ Further characteristics of seal oil were noted above in Bk XI, Ch. 23, where I described how during a siege, if it is poured on the channels of water you have opened up in the ice, it stops them from freezing over.