Proverbs 25:20

[As] he that taketh away a garment in cold weather
Either takes it off of himself, or another person, when it would be rather more proper to put another garment on, and so is exposed to the injury of cold weather; [and as] vinegar upon nitre:
nitre was found in Egypt, beyond Memphis, as Strabo says ^F16; there were two mines of nitre, which produced much, and thence it was called the Nitriotic Nome: others say, nitre has its name from Nitria, a town in Egypt ^F17, which gives name to the Nitrian desert, where there is a lake called Latron; from the bottom of which, that sort of nitre, called Natron, arises to the top, as is apprehended, and there, by the heat of the sun, condenses into this kind of substance ^F18, which will react with an acid; and so vinegar poured upon it will irritate and disturb it, cause it to react, and make a noise and a hissing. This must be understood only of this sort of nitre, of the nitre of the ancients; not of the moderns, which is no other than saltpetre; for though this will ferment with vinegar, saltpetre will not ^F19: nitre is dissolved by a liquid, but not any, only that which is cold, as Aristotle observes ^F20, as is vinegar; and therefore, with great propriety, this is joined to what goes before; so [is] he that singeth songs to a heavy heart;
rather distresses and afflicts him the more; as he cannot sing himself, he cannot bear to hear others sing; such rather should be condoled and wept with than to have songs sung to them. Some understand the words in a sense the reverse; the word rendered taketh away, in the first clause, has the signification of adorning with a garment; hence they render it, "as he that putteth on a garment ^F21 for ornament in cold weather, and as vinegar to nitre, so is he that singeth songs to a heavy heart"; that is, as an additional garment drives away cold, and vinegar dissolves nitre, so singing songs to a heavy hearted man drives away sorrow; as in the case of Saul, such an effect had music on him, ( 1 Samuel 16:21 ) ; or rather, to put on a thin garment for ornament in cold weather is as absurd and unseasonable as to put vinegar to nitre, or to a wound, as Schultens, and to sing songs to a heavy heart; all absurd.