'Grass' is natural truth, and 'flower of the field' is spiritual truth, as in Isaiah 40:5, 6. Green grass, in the Word, signifies the good and truth of the church, and of faith, which first springs up in the natural man. This is also signified by 'herb in the field.' Grass and the pulse of the herb, as in Psalm 32:2, signify what is most vile. Grass signifies science from a spiritual origin, or that by which spiritual truth is confirmed. 'Reeds and rushes' signify science from a sensory origin, or the things which confirm the fallacies of the senses, as in Isaiah 25:7. This science, considered in itself, is only a part of the lowest natural degree, which may be justly called material and bodily, in which there is little or no life. Green grass also signifies that which is alive with man. 'Grass burnt up' signifies the things which are dead in him. Grass signifies the scientific principle. Just as green grass serves animals for support, spiritual truth serves men for spiritual nourishment.

(références: Apocalypse Explained 507)

508. Verses 8, 9. And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea; and the third part of the sea became blood. And there died the third part of the creatures in the sea having souls; and the third part of the ships was destroyed.

8. "And the second angel sounded" signifies influx out of heaven, and the second consequent change with the evil (n. 509); "and as it were a great mountain burning with fire," signifies the love of self and of self-intelligence therefrom n. 510; "was cast into the sea," signifies into the natural man (n. 511); "and the third part of the sea became blood," signifies that in consequence everything therein became falsity of evil n. 512.

9. "And there died the third part of the creatures in the sea having souls," signifies that in consequence every living knowledge [scientificum] in the natural man perished n. 513; "and the third part of the ships was destroyed," signifies that all knowledge of truth and good from the Word and from doctrines from the Word also perished (n. 514).