Many of the vessels here bear legible inscriptions relating to alchemical work: I could read Magiscana Perlaram, Sal Momia, Mercuria Coralatus fe, Aqua Paradiso & others. Of all the works in the Four Elements series, this is the one that is clearly about man-made things (not nature) and in particular its theme seems to be transformation and artifice. Apart from the money and the weapons, which are in the center, the two sides each treat means of transformation, what we would call mechanical on left and chemical on right. The kunstkammer-ish collection on left seems to have an unusual number of tools in it--lots of little tools for hand crafts, the tools that are used in various ways to make the vessels that are also shown. Pliers and hammers and various things that grasp or saw; there are more of those in with the weapons. Copy in Paris, Louvre, inv. #4007 (copper, 47 x 68); copy Stuttgart, Wurttembergische Staatsgalerie,1931 cat. #613 (copper, 46 x 67). This image/series was replicated less often than the Lyons and Doria Pamphili ones, but there are indeed some copies.

First mentioned letter of Feb. 1, 1608: He would have started inventing the element of fire but it is too cold (possibly a joke).
Mentions in letter to Bianchi of June 13, 1608: the Fire will be diabolical in invention and full of work (details).

Sept. 26, 1608 to Borromeo: In a few days he will send the Element of Fire. In the painting there are all kinds of armory/metals of gold and Silver.

Dec. 12 1608, to Bianchi: Brueghel has delivered into the hands of sig. Lavelli "un casetto" containing 3 paintings: a Saint Anthony, beautiful and rare flowers, and the Element of Fire.

Letter to Borromeo, 4 July 1609. “gli doi paisetto per terra et aqua, poi che l’aria et fuoco sonne fatte con figurini nudi. Detta doi con glia tri farra farre di cornice belli, et io darra certa botte del pinello, che tornerane a Milano transformate. L aria et fuoco io spera aver finite questo mesa al agosto, et subito serra inviata” (Crivelli, pg. 139).

August 1 to Bianchi: expects to finish Fire this month.

Letters to Borromeo, 27 August 1609. “et con il tempo comencira l altri dui Aqua et terra.” (Crivelli, pg. 147).

Letter to Borromeo, May 1610. “VS me scusera che ho tardato tanto con questo mio quadretto Ellemento del fuco” (Crivelli pg. 152)

Letter to Borromeo, 25 March 161. “Con mio piacer intende in content che VS ha in el quareto ellementa del fuoco. Glia tri tre Aria Terra et Aqua non serrane mancho che el primo” (Crivelli, pg. 166).

Letter to Borromeo,19 April 1613. “di server Su. S. lll.ma nel quadro di quel elemento che commanda si faccia, con ogni affettione et industria; per conto el paradise non ho da dir altro” (Crivelli, pg. 205).