Exodus 16:14

ותעל שכבת הטל וגו׳ AND WHEN THE LAYER OF DEW WENT UP etc. — When the sun rose the dew which was lying upon the Manna ascended sunward, as is the manner of dew — that it ascends sunward; even if you were to fill an egg-shell with dew and close up its opening and place it in the sun, it (the egg-shell with the dew in it) will rise of its own accord into the air, (in consequence of the tendency of the dew to rise upwards). — But our Rabbis explained that these words imply that the dew rose from the ground into the air. — When the layer of dew went up the Manna became visible, and they looked, (cf. Midrash Tanchuma, Beshalach 20; Shemot Rabbah 38:4) והנה על המדבר דק AND BEHOLD, UPON THE SURFACE OF THE DESERT there was etc. דק, a THIN object, מחספס uncovered — and there is no other example of this word in the Scriptures. One may also explain מחספס as having the same meaning as חפיסה in (Mishna Bava Metzia 1:8) חפיסה ודלוסקמא, “a valise and chest”, in Mishnaic Hebrew, and the meaning would be, that when it became uncovered from the layer of dew they saw that there had been a thin object enclosed in it i. e. enclosed between the two layers of dew. Onkelos translates it by מקלף peeled (flaky), taking מחספס in the sense of, and from a similar root as, (Genesis 30:37) “peeling off (מחשף) the white”. ככפר AS HOAR FORST — כפר is old French gelide. The Targum renders דק by דעדק כגיר, the word גיר occurring in (Isaiah 27:9) “גיר-stones” — this is a kind of black colour — just as we enumerate amongst the kinds of earth which may be used for covering the blood of a wild animal or bird after it has been slaughtered “powdered chalk (גיר) and orpiment” (Chullin 88b). Onkelos renders the entire phrase by “powdered like גיר, like hoar-frost upon the ground”, meaning that it was as fine as גיר and lay congealed as frost in the ground. This is therefore the meaning of דק ככפור: “spread out fine but yet one atom hanging to another like hoar-frost”. דק is old French tenuis — meaning that it formed a thin incrustation on top. The word וכגיר which Onkelos has in his translation is an addition to the Hebrew text, there being no word corresponding to it in the verse.

וַתַּ֖עַל שִׁכְבַ֣ת הַטָּ֑ל וְהִנֵּ֞ה עַל־פְּנֵ֤י הַמִּדְבָּר֙ דַּ֣ק מְחֻסְפָּ֔ס דַּ֥ק כַּכְּפֹ֖ר עַל־הָאָֽרֶץ׃

And when the layer of dew was gone up, behold, upon the face of the wilderness there lay a fine flaky substance, as fine as the hoar frost on the ground.