Seward daily gateway., 1932-05-06

Bay and begins mapping that DOT tion of the Territory under the direction of s. M. Farrar and his assistant, c. Blattmann.
 Primarily, the photographic work, such as has been carried on about the Seward harbor, is for the purpose of providing an accu- rate typographical map for the use of the Coast and Geodetic Survey and other departments. However, it is altogether possible that Ste phen R. Capps, who in the present instance has become marine prospector-principally in finding a part of the ship where it rolls least-will add to. his experiences that of reading the geologic phe- nomena from the air.
 Prospecting for precious minerals by airplane is now a recognized departure of mineral science. Air planes are being used extensively in preliminary work, thus bridg- a wide gap between the grizzled knight of the burro and plenty of whiskers and the places where gold and other precious metals may be found.
 Equipment Same as For Mapping
 The equipment for this work consists of practically the same inn plements employed in mapping from the air. This consists of a fast, powerful, stable cabin plane, one which will not yaW and which will, in the words of the pilot, fly "hands off," and specially de- signed photographing apparatus.
 The photographic map obtained with this camera is compoSit or mosaic made from a series of skill fully matched vertical shots which must be true vertical exposures taken at the same distance from the earth and at right angles to the earth's surface, both in line of flight and in lateral direction.
 The pilot working usually in high attitudes is handicapped by a scar city of oxygen and impeded by his necessary heavy clothing. Never theless, he must fly an even keel, compensate for every vagary of wind, updraft or downdraft. He must see and retain in his memory the location of ground objects, perhaps over 50-mile strip, that a layman would not discern if they were pointed out to him. He must instruct his photographer when to start taking pictures. He must re- member his boundaries; always he must fly predetermined compass course.
 The camera man, to keep his in- strument at a true vertical, is aid ed by gimbal joint and spirit level which he must in turn ad- just for unavoidable, sudden move ments of the ship.
 Perfect Coordination Required
 Quite frequently in mountainous country, vertical air movements known as bumps" will be encoun- tered A downdraft can drop a ship abruptly hundreds of feet in one second. In the next instant, like a shot, an updraft can lift it again 500 feet above the original position. So constantly, the cam era man must be on the alert.
 Shots are so made that they will overlap 60 per cent in the line of flight and 50 per cent literally. The geologist is thus able to study individual shots to follow a ledge or stream from one photograph on to the next.
 Every flaw in the landscape is shown by nature; these flaws are what the geologist seeks, to best advantage, in the full dress of green vegetation. Vegetation var ieS in character with soil so that the line of demarkation between a fault and adjacent soil is shown distinctly.
 So great must the care be in talk ing these aerial photographs, either for mapping or prospecting, that they must be taken as near as pos sible at the same time of day, otherwise shadows may change the