Land Magnetic Observations, 1905-10 



Table 1. Details and Constants of Magnetometers Used. 



' The magnets are hollow steel bars with cross-scjction of octagonal periphery on the outside and circular on inside. 



' The magnets are hollow cylinders. 



'The magnets are solid cylinders; long magnet system (No. 1) is marked by one dot on magnets; long magnet 



system (No. 2), by two dots on magnets. 

 *The values given under the heading P are values of P' assuming that (1 + P'r'^) = (1 + Pr~' + Qr~*), 

 'Values used after the accident of March 28, 1910, are P = + 15.56 and Q = - 570. 



