FOG STUDIES ON MOUNT TAMALPAIS. 



535 



FOG STUDIES OX MOUNT TAMALPAIS. 



By ALEXANDER McADIE. 



nr ATE on a February afternoon the passengers on a large Pacific 

 -L^ Mail steamship sighted the Farallones and doubtless thought as 

 the pilot came aboard that the long run across the broad ocean not 

 always true to its name was safely over and danger past. The 'Rio de 

 Janeiro' came to anchor a little before six o'clock on Thursday night, 

 February 21, 1901, and the weather being foggy, the captain wisely 

 remained at anchor until about 4 a. m. when the fog lifted. The lights 

 of the Cliff House two or three miles away could be seen and the vessel 

 started on a northeast course with Lime Point dead ahead. There is 

 some difference of testimony as to whether the Captain or Pilot gave 

 the order to go ahead. The fog closed down again and the Pilot steered 

 by the whistle hoping to get the echo from Point Diablo. Xo echo 

 was heard. The vessel was not moving at full speed, the First Officer 

 was standing on the starboard side listening for the Fort Point bell and 

 the Captain and Pilot were on the bridge. No soundings however 

 were taken. At about 5 :30 a. m. the vessel struck the Fort Point 

 Reef, backed off and within twenty minutes had gone from sight with 

 130 of the 210 persons aboard. 



The two diagrams herewith show the general approach to the Bay 

 of San Francisco and in more detail the probable path steered by the 

 'Rio' with zones of inaudibility of the fog signals. 



When all is said and done it appears that the fog was the prime 

 cause of this appalling accident. Now, while an accident of such 

 magnitude gives startling emphasis to the need of studying fog, a sum- 

 mation of the minor accidents for a single year due to fog in any large 

 seaport would be equally impressive. One cannot cross the sea, run 

 down the coast or even go over a bay upon a ferry-boat without experi- 

 encing at times this troublesome condition. Nor is it only when on 

 the water that we are at the mercy of the fog. Study the statistics of 

 railway accidents and you will be surprised how often, in the column 

 giving the cause of collision or other accident, the word fog appears. 

 Can we help ourselves? Yes; and the first step is to study patiently 

 and systematically the various types of fog formation. Already the 

 ability to communicate by means of wireless telegraphy between vessels 

 at sea and the land removes the greatest element of danger to vessels 

 caught in fog. The 'Rio de Janeiro' was lost at the entrance to 



