Amid the terrors of such a calamity it is difficult to obtain observations possessing any scientific value. Fortunately, however, there was in the city a physicist trained to observe phenomena of this character, Professor George Davidson of the University of California. Like others, he had been awakened by the first severe shock. At once recognizing the nature of the phenomenon, and desirous of obtaining the exact time of its occurrence, he counted seconds while he ran towards the table on which he had placed his watch, and in this way estimated that the shock occurred at twelve minutes past five in the morning. The closeness of this observation is emphasized by the fact that it differed from the recorded time by only six seconds. He states that the motion, at the time of its greatest intensity, closely resembled that of a rat vigorously shaken by a terrier.
The destruction caused by the earthquake was, however, but a small part of the total loss to the city. Fires were almost immediately started in the ruined houses by the fires in the kitchens and other parts of the houses, by the ignited jets of the illuminating gas, and, perhaps, especially, by the crossing of numerous electric light wires.
The manner in which the woodwork and other combustible materials of the buildings were loosely tossed together by the shocks helped the quick spread of the fires, and this, too, was probably greatly aided by the illuminating gas from the broken gas pipes and mains. Eight severe conflagrations were, therefore, soon raging in different parts of the doomed city. What made these fires especially dangerous was the fact that the earthquake shocks had destroyed the water pipes. Thus the firemen were handicapped in their heroic endeavors to extinguish the flames.
At the time of the fire a strong wind was blowing from the northeast. Since the firemen were unable to check the flames, the fire line rapidly advanced. Its path led towards the best residential parts of the city through portions of the mission section containing a dense population of poor people. The dwellings in this latter section consisted of frame houses, through which the flames rapidly spread.
There was but one way to save the city from total destruction—a free use of dynamite! This was intelligently employed until the supply gave out, when it seemed that the city was doomed to utter destruction. But at the last moment, as it were, came a lucky change in the direction of the wind. Instead of blowing from the northeast, the steady southwest winds set in, and beat back the fire on itself, so by Friday, the 18th being Wednesday, it was under complete control and the rest of the city was saved.
A San Francisco Pavement Torn by the Earthquake
From a Stereograph, Copyright, 1906, by Underwood & Underwood
The extent of the fire is thus described in an article in the "Outlook," for Saturday, April 28th, 1906, as follows: