PULMONAR--(1) For the symptoms you describe, try the Gobi Desert Sanatoria. The low levels of most of the Saharan Sanatoria are against them except at the outset of the disease. (2) We do not recommend boarding-houses or hotels in this column. BEGINNER--On still days the air above a large inhabited city being slightly warmer--i.e., thinner--than the atmosphere of the surrounding country, a plane drops a little on entering the rarefied area, precisely as a ship sinks a little in fresh water. Hence the phenomena of “jolt” and your “inexplicable collisions” with factory chimneys. In air, as on earth, it is safest to fly high. EMERGENCY--There is only one rule of the road in air, earth, and water. Do you want the firmament to yourself? PICCIOLA--Both Poles have been overdone in Art and Literature. Leave them to Science for the next twenty years. You did not send a stamp with your verses. NORTH NIGERIA--The Mark Boat was within her right in warning you off the Reserve. The shadow of a low-flying dirigible scares the game. You can buy all the photos you need at Sokoto. NEW ERA--It is not etiquette to overcross an A. B. C. official's boat without asking permission. He is one of the body responsible for the planet's traffic, and for that reason must not be interfered with. You, presumably, are out on your own business or pleasure, and must leave him alone. For humanity's sake don't try to be “democratic.” EXCORIATED--All inflators chafe sooner or later. You must go on till your skin hardens by practice. Meantime vaseline. REVIEW The Life of Xavier Lavalle (Reviewed by Rene Talland. École Aëronautique, Paris) Ten years ago Lavalle, “that imperturbable dreamer of the heavens,” as Lazareff hailed him, gathered together the fruits of a lifetime's labour, and gave it, with well-justified contempt, to a world bound hand and foot to Barald's Theory of Vertices and “compensating electric nodes.” “They shall see,” he wrote--in that immortal postscript to The Heart of the Cyclone--“the Laws whose existence they derided written in fire beneath them.” “But even here,” he continues, “there is no finality. Better a thousand times my conclusions should be discredited than that my dead name should lie across the threshold of the temple of Science--a bar to further inquiry.” So died Lavalle--a prince of the Powers of the Air, and even at his funeral Cellier jested at “him who had gone to discover the secrets of the Aurora Borealis.”