The water of the Fountain of the Sun was, at different periods of each twenty-four hours, successively _hot_ and _cold_: “Aquam enim habet, cum horis diei miris subinde vicibus re variantem. Nam sub lucis ortum tepidam emittit. Die hinc progrediente pro horarum succedentium ratione, frigescit. Sub æstum vero meridianum frigedo ejus summa est. Quæ rursùs parili modo remittit usque ad vesperam. Tunc appetente nocte rursùs incalescit, ad mediam usque noctem, ubi exæstuat. Exinde calor sensìm deficit: donec unà cum exortâ luce pristinam teporis vicem recuperârit.” Diod. Sic. Tom. II. edit. Wesseling, p. 199. Mr. Horneman appears to have made no inquiries on this curious subject; but tells us, that having asked, “if there was any spring of fresh water near?” he was shewn to the one he describes, undoubtedly the _nearest_, and probably the same as seen by Mr. Brown, who says, (p. 24 of his Volume of Travels), “that one of the springs which rise near the ruins described, is observed by the natives, to be _sometimes cold and sometimes warm_.” Mr. Brown does not appear to have considered the Oasis of Siwah as that of Ammon. He had no favourite discovery to set forth and confirm by particular remarks and circumstances: he had not an interest in his account of the changeable temperature of this spring, but that of truth. The periodical variation from hot to cold, and from cold to heat, may rather, therefore on his relation, be assumed as fact; and be taken as a matter of proof concurrent with the grove, the spring itself, the distance from the ruins, and the beauty of the situation, _all_ answering to the descriptions of the _Fountain of the Sun_, given by ancient writers, and, in reference to the ruins, rendering the conjecture more probable, that they are those of the Temple of Ammon.