By his neesings a light doth shine - The word rendered "neesings" means properly sneezing, and the literal sense here would be, "His sneezings, light shines." Coverdale renders it, "His nesinge is like a glisteringe fyre." Bochart says that the meaning is, "that when the crocodile sneezes, the breath is driven through the nostrils with such force that it seems to scintillate, or emit fire." Probably the meaning is, that when the animal emits a sudden sound, like sneezing, the fire seems to flash from the eye. There is some quick and rapid motion of the eyes, which in the rays of the sun seem to flash fire. The sneezing of the crocodile is mentioned by Aristotle. Prof. Lee. Amphibious animals, the longer they hold their breath under water, respire so much the more violently when they emerge, and the breath is expelled suddenly and with violence. Schultens. This is the action here referred to - the strong effort of the animal to recover breath when he rises to the surface, and when in the effort the eyes seem to scintillate, or emit light.
And his eyes are like the eyelids of the morning - The "eyelids of the morning" is a beautiful poetic phrase quite common in Hebrew poetry. The eyes of the crocodile are small, but they are remarkable. When he lifts his head above water, his staring eyes are the first things that strike the beholder, and may then with great beauty be compared with the morning light. There is a remarkable coincidence here, in the fact that when the Egyptians would represent the morning by a hieroglyphic, they painted a crocodile's eye. The reason assigned for this was, that before the whole body of the animal appeared, the eyes seemed to rise from the deep; see Bochart on the passage, "Hierez.," and also Herapollo, "Hieroglyph." i. c. 65.

By his neesings a light doth shine - It is very likely that this may be taken literally. When he spurts up the water out of his nostrils, the drops form a sort of iris or rainbow. We have seen this effect produced when, in certain situations and state of the atmosphere, water was thrown up forcibly, so as to be broken into small drops, which has occasioned an appearance like the rainbow.
The eyelids of the morning - It is said that, under the water, the eyes of the crocodile are exceedingly dull; but when he lifts his head above water they sparkle with the greatest vivacity. Hence the Egyptians, in their hieroglyphics, made the eyes of the crocodile the emblem of the morning. Ανατολην λεγοντες δυο οφθαλμους κροκοδειλου ζωογραφουσι. - Horapp. Egypt. Ieroglyph., lib. i., c. 65. This is a most remarkable circumstance, casts light on ancient history, and shows the rigid correctness of the picture drawn above. The same figure is employed by the Greek poets.
Χρυσεας ἡμερας βλεφαρον.
"The eyelid of the golden day."
Soph. Antig. ver. 103.
Νυκτος αφεγγες βλεφαρον.
"The darksome eyelid of the night."
Eurip. Phaeniss. ver. 553.

By his neesings (g) a light doth shine, and his eyes [are] like the eyelids of the morning.
(g) That is, casts out flames of fire.

By his neesings a light doth shine,.... The philosopher (i) observes, that those who look to the sun are more apt to sneeze: and it is taken notice of by various writers (k), that the crocodile delights to be sunning itself, and lying yawning in the sun and looking at it, as quoted by Bochart; and so frequently sneeze: which sneezings, through the rays of the sun, may seem to shine and give light. Though as, in sneezing, water is thrown out through the nostrils, it may be observed of the whale, that it has mouths or holes in its front, through which, as through pipes, it throws out showers and floods of water, as Pliny (l) relates; which, by means of the rays of the sun, as in a rainbow, appear bright and glittering;
and his eyes are like the eyelids of the morning: the break and dawn of day; a very beautiful expression, the same we call "peep of day": Pindar (m) has "the eye of the evening"; break of day, as Ben Gersom says, is about an hour and the fifth part of an hour before the sunrising. The eyes of the crocodile were, with the Egyptians, an hieroglyphic of the morning (n): wherefore this seems better to agree with the crocodile than the whale, whose eyes are not much bigger than those of a bullock; and has eyelids and hair like men's eyes; the crystal of the eye is not much bigger than a pea (o); its eyes are placed very low, almost at the end of the upper lip, and when without its guide, dashes itself against rocks and shoals (p). Though that sort of whales called "orcae" are said to have eyes a foot long, and of a red rosy colour, such as the morning is described by (q); and a northern writer (r) tells us that some whales have eyes, whose circumference will admit fifteen or twenty men to sit therein; and in others it exceeds eight or ten cubits; and that the pupil is a cubit, and of a red and flaming colour; which, at a distance, in dark seasons, among the waves, appears to fishermen as fire kindled. And Thevenot (s) says of crocodiles, that their eyes are indifferently big, and very darkish.
(i) Problem. s. 33. qu. 4. (k) Aelian. l. 3. c. 11. Leo African. Descriptio African, l. 9. p. 761. Pet. Martyr. Decad. 3. c. 4. (l) Nat. Hist. l. 9. c. 4, 6. (m) Olymp. Ode 3. v. 36. (n) Hor. Hiereglyph. apud Scheuchzer. vol. 4. p. 849. (o) Voyage to Spitzbergen, p. 145. (p) Aelian. l. 2. c. 13. Plin. l. 9. c. 62. (q) Hasacus apud Schultens in loc. (r) Olaus Magnus de Ritu Gent. Septent. l. 21. c. 5, 8. so Albertus Magnus de Animal. l. 24. c. 1. (s) Travels, ut supra, (part. 1.) p. 245.

Translate: "his sneezing, causeth a light to shine." Amphibious animals, emerging after having long held their breath under water, respire by violently expelling the breath like one sneezing: in the effort the eyes which are usually directed towards the sun, seem to flash fire; or it is the expelled breath that, in the sun, seems to emit light.
eyelids of morning--The Egyptian hieroglyphics paint the eyes of the crocodile as the symbol for morning, because the eyes appear the first thing, before the whole body emerges from the deep [HorÃ&brvbr; HierogliphicÃ&brvbr; 1.65. BOCHART].

18 His sneezing sendeth forth light,
And his eyes are like the eyelids of the dawn;
19 Out of his mouth proceed flames,
Sparks of fire escape from him;
20 Out of his nostrils goeth forth smoke
Like a seething pot and caldron;
21 His breath kindleth coals,
And flames go forth out of his mouth.
That the crocodile delights to sun itself on the land, and then turns its open jaws to the sunny side, most Nile travellers since Herodotus have had an opportunity of observing;
(Note: Dieterici, Reisebilder, i. 194: "We very often saw the animal lying in the sand, its jaws wide open and turned towards the warm sunbeams, while little birds, like the slender white water-wagtail, march quietly about in the deadly abyss, and pick out worms from the watery jaws." Herodotus, ii. 68, tells exactly the same story; as the special friend of the crocodile among little birds, he mentions τὸν τροχῖλον (the sand-piper, Pluvianus Aegyptius).)
and in connection therewith the reflex action of sneezing may occur, since the light of the sun produces an irritation on the retina, and thence on the vagus; and since the sun shines upon the fine particles of watery slime cast forth in the act of sneezing, a meteoric appearance may be produced. This delicate observation of nature is here compressed into three words; in this concentration of whole, grand thoughts and pictures, we recognise the older poet. עטשׁ is the usual Semitic word for "sneezing" (Synon. זרר 2-Kings 4:35). תּהל shortened from תּהל, Job 31:26, Hiph. of הלל. The comparison of the crocodile's eyes with עפעפּי־שׁחר (as Job 3:9, from עפעף, to move with quick vibrations, to wink, i.e., tremble), or the rendering of the same as εἶδος ἑωσφόρου (lxx), is the more remarkable, as, according to Horus, i. 68, two crocodile's eyes are the hieroglyph
(Note: The eyes of the crocodile alone by themselves are no hieroglyph: how could they have been represented by themselves as crocodile's eyes? But in the Ramesseum and elsewhere the crocodile appears with a head pointing upwards in company with couching lions, and the eyes of the crocodile are rendered specially prominent. Near this group it appears again in a curved position, and quite small, but this time in company with a scorpion which bears a disc of the sun. The former (κροκοδείλου δύο ὀφθαλμοί) seems to me to be a figure of the longest night, the latter (κροκόδειλος κεκυφώς in Horapollo) of the shortest, so that consequently ἀνατολή and δύσις do not refer to the rising and setting of the sun, but to the night as prevailing against or succumbing to the day (communicated by Lauth from his researches on the astronomical monuments). But since the growth of the day begins with the longest night, and vice vers, the notions ἀνατολή and δύσις can, as it seems to me, retain their most natural signification; and the crocodile's eyes are, notwithstanding, a figure of the light shining forth from the darkness, as the crocodile's tail signifies black darkness (and Egypt as the black land).)
for dawn, ἀνατολή: ἐπειδ́περ (probably to be read ἐπειδὴ πρὸ) παντὸς σώματος ζώου οἱ ὀφθαλμοὶ ἐκ τοῦ βυθοῦ ἀναφαίνονται. There it is the peculiar brilliancy of the eyes of certain animals that is intended, which is occasioned either by the iris being furnished with a so-called lustrous substance, or there being in the pupil of the eye (as e.g., in the ostrich) that spot which, shining like metal, is called tapetum lucidum. For ἀναφαίνεσθαι of the eyes ἐκ τοῦ βυθοῦ, is the lustre of the pupil in the depth of the eye. The eyes of the crocodile, which are near together, and slanting, glimmer through the water, when it is only a few feet under water, with a red glow.
Nevertheless the comparison in Job 41:18 might also be intended differently. The inner (third) eyelid
(Note: Prof. Will refers the figure not to the third eyelid or the membrana nictitans, but to that spot on the choroidea, glistening with a metallic lustre, which the crocodile has in common with most animals of the night or the twilight, therefore to the brilliancy of its eye, which shines by virtue of its lustrous coating; vid., the magnificent head of a crocodile in Schlegel's Amphibien-Abbildungen (1837-44).)
of the crocodile is itself a rose red; and therefore, considered in themselves, its eyes may also be compared with the "eyelids of the dawn." What is then said, Job 41:19, of the crocodile, Achilles Tatius, iv. 2, says of the hippopotamus: μυκτὴρ ἐπὶ μέγα κεχῃνὼς καὶ πνέων πυρώδη καπνὸν ὡς ἀπὸ πηγῆς πυρός. Bartram has observed on the alligator, that as it comes on the land a thick smoke issues from its distended nostrils with a thundering sound. This thick, hot steam, according to the credible description which is presented here, produces the impression of a fire existing beneath, and bursting forth. The subjective truth of this impression is faithfully but poetically reproduced by the poet. On כּידוד (root כד, escudere). התמלּט signifies no more than to disentangle one's self, here therefore: to fly out in small particles. אגמון, Job 41:19, is rendered by Saad., Gecat., and others, by qumqum (קומקום), a caldron; the modern expositors derive it from אגם = agama, to glow, and understand it of a "heated caldron." But the word signifies either heat or caldron; the latter signification, however, cannot be linguistically established; one would look for אגּן (Arab. iggâne, a copper Germ. Waschkessel). The noun אגמון signifies, Job 40:2, the reed σχοῖνος, and in the Jerusalem Talmud, Sota ix. 12, some menial service (comp. Arab. ugum); Ew. rightly retains the former signification, like a pot blown upon, i.e., fired, heated, and beside it (in combination with it) reeds as fuel, which in themselves, and especially together with the steaming water, produce a thick smoke. The Waw is to be compared to the Arabic Waw concomitantiae (which governs the acc.).

Sneesings - This the crocodile is said frequently to do. Eyes - To which they seem very fitly compared, because the eyes of the crocodile are dull and dark under the water, but as soon as they appear above water, cast a bright and clear light; like the morning light, suddenly breaking forth after the dark night.