"The frame thereof seemed partly circulare,
And part triangulare," &c.
Warton (_Observations on the Fairy Queen_, vol. i. p. 121.) says that
the philosophy of this abstruse stanza describing the Castle of Alma is
explained in a learned epistle of Sir Kenelm Digby addressed to Sir
Edward Stradling. In a foot-note he states that this epistle was--
"First printed in a single pamphlet, viz., _Observations on XXII
Stanza, &c._, Lond. 1644, 8vo. It is also published in Scrinia
Sacra, 4to. pag. 244. London, 1654."
Could any of your readers, acquainted with Sir Kenelm Digby's works,
give his explanation of this stanza? There is no note on it in the
one-volume edition of Spenser lately published by Moxon. The best
explanation of it that I have seen is in the _Athenaeum_, August 12,
1848.