136 



SCIENCE 



[N. S. Vol. XXIX. No. 734 



there can be little question that it has en- 

 couraged unwise construction, not only in 

 San Francisco but in other parts of the 

 malloseismic district. 



The policy of concealment is vain, be- 

 cause it does not conceal. It reflects a 

 standard of commercial morality which 

 is being rapidly superseded, for the suc- 

 cessful salesman to-day is he who repre- 

 sents his goods fairly and frankly. It is 

 unprofitable, because it interferes with 

 measures of protection against a danger 

 which is real and important. 



To understand the practical importance 

 of the earthquake danger, let us for a mo- 

 ment consider it from the insurance point 

 of view. To determine rate of premium, 

 an insurance company first computes the 

 risk, and this computation is based on past 

 eixperience, comparing the actual losses 

 with the amount exposed to loss. We 

 know, with fair approximation, the loss of 

 life by earthquake in California from the 

 year 1800, and can compare it with the 

 population. As to the property loss, our 

 knowledge is relatively indefinite, but it 

 suffices for the present purpose. 



Consider first the value of insurance 

 against the danger of death by earthquake. 

 Seven hundred and nine deaths are re- 

 ported to have been caused by the San 

 Francisco earthquake, and about 76 deaths 

 by earlier earthquakes, making a total of 

 785.^° The total annual population for 

 the same period, that is to say, the sum of 

 the populations for the several years, was 

 about 51,500,000." Using these data, the 



"■The casualties in 1906 are given as reported 

 by the State Board of Health; those in earlier 

 years were compiled from Holden's " Catalogue 

 of Earthquakes on the Pacific Coast, 1769 to 

 1897." 



"To obtain this figure the populations of the 

 state on census years were platted on section 

 paper and a curve of population dravm through 

 them, thus graphically interpolating estimates for 

 intervening years. For years earlier than 1850 



annual premium on a policy for $1,000, 

 payable only in the event of death by 

 earthquake, is computed at one cent and a 

 half, plus the cost of doing the business 

 and the profit of the company. The 

 minuteness of the earthquake risk may be 

 further indicated by saying that it is one 

 tenth of the risk of death by measles. If 

 a timid citizen of California should emi- 

 grate in order to escape the peril from 

 earthquake, he would incur, during his 

 journey, a peril at least two hundred times 

 as great, whether he traveled by steamship, 

 sailing vessel, railway car, motor car, 

 stage, private carriage, or saddle; and if 

 in emigrating he removed from San Fran- 

 cisco to Washington City he would incur, 

 by change in environment as regards 

 typhoid fever, an increment of peril 

 eighteen times as great as the earthquake 

 peril he escaped.^^ 



The danger to property is much more 

 serious. Using the same method of com- 

 putation as before, and availing myself of 

 the expert knowledge of local statisticians, 

 I have made a parallel estimate of the 

 earthquake risk to buildings in California, 

 and find it to be about five hundred times 

 as great as the risk to life. If a company 

 were to undertake the insurance of build- 

 ings against injury by earthquake, and 

 base its premium on the experience of the 

 state from 1800 to 1908, the average 

 premium on a policy of $1,000 would be 

 about $7, plus the cost of doing the busi- 

 estimates were based on data contained in Hit- 

 tell's " History of California." The census returns 

 do not include Indians. In making estimates of 

 the population previous to 1S50 the Mission In- 

 dians were included. The estimate includes the 

 year 1908. 



" The U. S. Census returns for the years 1901-5 

 give the following death rates, per 100,000, from 

 typhoid: San Francisco, 27.0; Washington, 56.6. 

 The statement in the text of course applies only 

 to the risk of death from typhoid; the death rate 

 from all causes was higher, in the same years, in 

 the western city than the eastern. 



