322 THE FUR SEALS OF THE PRIBILOF ISLANDS. 



Oil the general map of the islands, scale 1:60,000, was done by Dr. Thomas C. Meiiden- 

 hall ill 1891, when he served as one of the Aniericau commissioners in the investigatiou 

 of the fur seals. The topography was supplied by Mr. Stanley-Brown. Dr. INIenden- 

 hall was on St. Paul from July 29 to August 9, and during that time investigated the 

 seal question, made observations for gravity, and did the triangulatioii. A base was 

 measured on the east side of the Lagoon with an ordinary stcol tape, and, from wlat 

 I can learn, no pressure balances were used and no corrections for temperature or 

 curvature were applied, and no signals were erected. 1 should call this triangulatioii 

 a reconuoissauce, and think Dr. Mendenhall claims no more for it. The topography by 

 Mr. Stanley-Brown was filled in by methods which I will refer to later. The survey 

 of St. George on the general chart, scale 1:00,000, was the work of Mr. Stanley- 

 Brown. 



The rookery surveys, scale 1 inch to 264 feet, were made with a plane table 

 according to (ieological Survey methods, and are entirely indeitendent of those pre- 

 viously mentioned. Each sheet stands by itself; tliat is, eacli rookery is a separate 

 survey and the rookeries on the different sheets were not connected. The bases were 

 measured with an ordinary steel tajie and no corrections were made nor pressure 

 balau<'es used. Tlie azimuths were observed by means of a compass attached to an 

 ordinary geologist's clinometer. (!airns were built of loose rock at prominent points 

 and Hags placed in favorable positions for observation points. No regular signals 

 were built, nor were angles observed nor computations made. The plane table was 

 l)laced over each end of the base successively and different points cut in, after which 

 these points were occupied and others made. No high or low water line was observ^ed; 

 the water line was cut in at the height it happened to be when the observations were 

 made. Tlie contoui's were traced with an aneroid barometer. The scale of the original 

 sheets is the same as that published — 1 inch to 264 feet, or 20 inches to the statute 

 mile. 



We tested these maps as thoroughly as our limited time would permit. Tlie 

 sheets accomi)anyiiig the fuller report will show tlie large number of angles observed, 

 and the data, though more or less incomplete, is suflicient to show thoroughly what 

 has been done in the past and what is required for the present and futiiie. I do not 

 think Mr. Stanley-Brown claims great accuracy for his maps. 1 should call them a 

 fair reconuoissauce. They are not accurate in the sense of a (inished survey; they 

 lack detail, and what is given is in most instances badly represented and indefiiiite; 

 the lines and symbols leave one constantly in doubt as to what is intended to be 

 understood. Yet, considering the means employed, the facilities, and the methods, it 

 is surjirising to me that they are as good as they are. These surveys by Mr. Stanley- 

 Brown are no doubt the very best for these islands that have ever been made, and he 

 deserves nothing but praise in carrying out the work under the many trying conditions. 



When the rookeries were so full of seals that a few tens of thousands, more or 

 less, was a matter of no importance, these maps served their purpose and served it 

 well; they were a good general guide. They satisfied the demands at the time they 

 were made, but as the number of seals have been so inucli reducjed and it is necessary 

 to make an estimate within small limits, we are unable with these maps to make an 

 eye survey of the areas occui)ied by the herd. 



The xiresent need recjuires a topographical map of the rookeries so accurate and 

 iu such detail that a person from an accessible position and commanding the rookeries 



