With its occult overtones and highly-strung language, this early disaster novel is more reminiscent of Poe and Lovecraft than it is of Wyndham or Christopher, for example.
It starts well. There is a spot of intrigue in London then our narrator, Adam Jeffson, sets sail for the Arctic in a ship packed to the gunwales with period details. After a spot more intrigue en route he reaches the North Pole, which is depicted here as a satisfyingly weird landscape. Amusingly, a completely redundant editor's note informs us that this description is not based on a true account. *
Meanwhile, a purple cloud envelops the rest of the world and poisons everybody. Returning south, Jeffson finds a macabre scene awaiting him, which he describes with some flair. He searches for other survivors, but finds none. This is unfortunate, not so much for him as for us, as the dearth of other characters results in a lack of drama in the long middle section of the book. The narrative drive fades away and Jeffson collapses into decadence. I suppose one should make allowances, given the extremity of his situation, but this is a man whose idea of a worthy activity is to build a bungalow of gold. His prose style doesn't help either. His habit of repeating, repeating words for emphasis starts to drag, and he has a fetish for detail, particularly concerning objects of the Near East, that transcends the evocative and ventures well into the realm of the tedious.
Eventually Jeffson finds a fragment of plot amidst the ruins of Istanbul, but it's too little, too late. Having started with enthusiasm, after 260 pages I was glad to leave his company.
* Excessive annotation is common fault of Penguin Classics, but this book is the worst example I've found. The notes are occasionally informative, but more usually inconsequential. Worse, some of them refer forward to events later in the book. I advise casual readers to ignore the asterisks, which litter the text like bird droppings.