Here's John Clute, from the newly-gone-live Science Fiction Encyclopedia (Third Edition), on Ingram:
INGRAM, KENNETH. (1882-1965) UK barrister, lay theologian, and author of some novels in the field of the fantastic, including two fantasies: The Symbolic Island: A Novel (1924), an abstractly mystical tale; and Midsummer Sanity (1933), in which Faerie and mortal Earth intersect at the summer solstice, at which point the denizens of the former convey wisdom to the denizens of the latter. Of sf interest are England at the Flood Tide (1924), which espouses a UTOPIAN Britain in which natural aristocrats rule a willing populace, and women have property rights; and The Premier Tells the Truth (1944), in which a truth DRUG causes fruitful disarray in the distant NEAR FUTURE. The Coming Civilization Will it be Capitalist? Will it be Materialist? (1935) is a nonfiction speculation.I discover that Ingram died precisely two days before I was born, so no overlap there. Phew! And of course, you know about the new online SFE3? If not, then haste to the site. There's good browsing there, as well as the answer to almost all SF-related questions.
Still, 'an abstractly mystical tale' isn't right for this novel (I picked up a copy in a Bracknell charity shop). It's much more specific and sciencefictional than that; and although it is certainly over-schematic and, frankly, not very good, it does have some interesting moments. So, a group of varied characters -- amongst them a middle-aged Civil Servant, a Capitalist, a retired Colonel, a Vicar (and his wife), a journalist with Socialist sympathies, and a philosopher -- are holidaying on a pleasant island off the coast of Cornwall. The neighbouring island, Tresala, houses the experimental laboratories of industrialist Lord Steinher, where is being developed a new super-weapon that, we're told, will 'revolutionise war'. As the novel starts Steinher himself is visiting the holiday island and is away from his labs, which is lucky for him, because a few pages in Tresala blows up ('a deafening thunder, a blinding crash, a convulsion ... the island of Tresala had suddenly been blotted out from existence and in its place was a wild crater belching out terrific angry clouds of smoke' 27). This smoke is actually some unnamed but new element, the active ingredient of the wonder-weapon; it settles around the island in a circular belt ('the belt destroys anything up to twenty-six thousand feet above it!' according to Steinher, which is a neat trick) and the people on the island are marooned. Some embrace the modestly utopian possibilities of their isolation; others fall back on authoritarian structures of control -- Steinher and the Colonel proclaim a militaristic regime, though others oppose them. The staff at the island's hotel, where everyone is staying, go on strike. Characters do that Magic Mountain-ish thing of talking about their various different world-views at one another with a persistence that approaches interminability. A storm threatens to move the killing 'band' of the poisonous wonder-weapon to the island, but in the event it dissipates the stuff and a steamer is able to get to the island and rescue everybody. The author's thumb slips into the balance at the end: the Vicar, having discussed religion with a Catholic on the island, has a sort of mystic vision and decides to convert. Ingram's slightly peculiar thesis is that, alone of all religions, Catholicism grants access to a 'sixth sense': '... the Catholic Religion produces, or rather develops a sixth sense in man. Other religions have a remarkable influence, but they do not quite do this' . That's the frequency, Kenneth? Really? Hmmm.