In 1876 Mortimer Collins referred to “The dusty and deliquescent pedestrian.” In 1845, Charles Darwin noted “Those salts answer best for preserving cheese which contain most of the deliquescent chlorides.” In 1874 Mordecai Cubitt Cooke pointed out that “It is very difficult to observe the structure of the hymenium, on account of its deliquescent nature.” And in 1866, in a textbook on botany, John Lindley and Thomas Moore included “Deliquescent..as the head of an oak tree.”
There are two things to observe here. First, that the word “deliquescent” seems to have been extremely popular in the 1800s, but since then has fallen into disuse. Second, that the word “deliquescent” seems to have meant several fairly different things all at the same time. Or did it?
“Deliquescent” comes from the Latin word “dēliquēscĕre,” meaning to dissolve, melt away, or disappear. In chemistry, deliquescent retains that precise meaning; it refers to a substance, particularly crystalline, that dissolves, usually in water. A popular high school (or earlier) chemistry demonstration is to expose some hygroscopic, deliquescent crystals to the air and watch them disappear as they absorb water vapor (that’s the hygroscopic part) and melt into a solution.
But “deliquescent” has a figurative meaning too, and that also goes back to the original Latin. It can be used in relation to people (or other subjects) to mean exhausting. That’s what the Collins’ mention of pedestrians is about.
The guy with the most interesting name in the above quotations, Mr. Cooke, is talking about a fungus, where “hymenium” is a layer of tissue where spores are produced. In many types of fungus, it seems that as soon as the spores appear the hymenium dissolves in to liquid. The “fruitfulness” of the fungus (technically producing spores is “fruiting”) simply dissolves. This has also been used as a figurative expression, at least by John Braine in the 1957 Room at the Top: “There was a middle-aged woman at the far side of the room with black dyed hair and a sort of deliquescent distinction.”
That leaves us with the reference to an oak tree. And here there really is a different usage; in botany, when the stem of a plant has lots and lots of branchings, producing ever-smaller stems, that’s also called “deliquescence.” Even this has been used figuratively. An issue of Artforum in 2009 suggested that “This past fall, with the consecutive openings of six ‘Asian biennials,’ the deliquescent 1990s and early-2000s trend toward establishing new large-scale exhibitions in increasingly far-flung locales bore fruit, such as it is.”
I’m not entirely sure who or what Artforum meant by “Asian biennials,” but the gist of it seems to be that art shows are proliferating like the branches at “the head of an oak tree.” Hopefully the sites are carefully chosen and waterproof, or they might find that the deliquescent exhibitions were created with deliquescent paint.
