A couple of points before I address the word itself:

- The colon in the passage appears incorrectly placed. It appears at the end of the first line of the quoted passage, when in fact it is part of the preceding passage. Until you figure it out, it can completely throw you off. I could not figure it out until I saw the same question on two different screens. The colon appeared at the end of the line on both screens, although the the last word in the line is different in each screen, based on different parameters (zoom level, resolution, font, font size, etc.). I then conducted an experiment by copying the text at the end of the first line continuing to the beginning of the second line. When I pasted that chunk elsewhere, the colon was nowhere to be found. It was not part of the copied text, because it belongs at the beginning of the line, not at the end.

- By now, I assume you have figured out that the writer of the text you are translating throws around all kinds of rhetorical flourishes here and there to give his writing the apperance of erudition, but he/she has no command of the devices that he/she employs. He/she just piles figures of speech upon figures of speech like there is no tomorrow. People who write this way have not earned the right to be taken absolutely seriously when translated. If you surrender your faith to every metaphor he/she employs, you will produce a terrible jumble in English. That is probably not a bad thing in itself, unless the idea is to produce a readable text.

Now to the word itself. This one is actually not bad at all. The figure alludes to a filtering process where a purified liquid is strained through a strainer of some kind. I believe that in this instance, the "distillation" metaphor works better in English, pointing to purification much more clearly and idiomatically.

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Note added at 16 hrs (2008-12-31 15:38:49 GMT) Post-grading
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I have just noticed that. Reading through it again, I see no direct object of the verb if we construe it in the active voice, unless it appears somewhere in the continuation of this long sentence. If we construe it in the passive voice, then the most logical subject of this verb is the word اتساقاً. If that is the case, then the translation wold be "is distilled." This mixes up the metaphor even more than I had thought.

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Note added at 17 hrs (2008-12-31 15:59:48 GMT) Post-grading
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Reading through the passage once again, I believe that the writer was groping for a different word. The word that would make sense here is ينضح, not يرشح. The writer must have the same mental decrepitude that I am beginning to experience in my sunset years, especially when I do interpreting work. If this theory holds, then Nadia Ayoub's suggestion, although bereft of any explanation, was on to something. And the frustration expressed by MOODI about the incongruity of this word as written is another indication of how this sentence simply does not work with this word.

I am now more inclined towards Nadi's "exudes."