764 THE POPULAR SCIENCE MONTHLY. 



room and office, the point at which a dangerously high temperature or 

 fire exists. 



For the protection of city blocks, a system of hydrants and pipes 

 placed on roofs has been suggested ; water at an ample pressure to be 

 constantly available. Very solid brick division-walls, carried up a few 

 feet above the roof, are desirable in such blocks. 



It may now be in order to state the progress of the mutual system 

 of underwriting, whose methods have been briefly presented. On 

 January 1, 1885, the nineteen associated Factory Mutual Insurance 

 Companies had at risk no less a sum than 1375,000,000, an amount 

 nearly twice as large as that at risk seven years before. During these 

 seven years the cost to the insurers in the leading company, the Boston 

 Manufacturers', had declined twenty-three per cent, as compared with 

 the cost during the years from 1850 to 1878. In the early part of this 

 latter period the volume of business was small, and the losses propor- 

 tionally greater than they afterward became. During 1884 the net 

 premiums paid by insurers in the Mutual companies averaged 28*28 

 cents per $100 insured. 



A few words as to the details of effecting the mutual insurance of 

 factories : Although the cost is currently but 28 cents per $100 per 

 annum, the companies charge rates averaging 80 cents, the difference 

 being returned as dividend. In addition to the payment of premium, 

 each insurer becomes liable for an assessment five times as great as the 

 premium. No such assessment has ever been called for in the history 

 of the Factory Mutual Companies. No policy is granted until compli- 

 ance with the companies' rules for construction, quenching apparatus, 

 and discipline in its use, has been ascertained by an inspector. His 

 further business is to pay frequent and unannounced visits to insured 

 premises, to see that all is as it should be. Disobedience to rules, or 

 culpable negligence, may be deemed sufficient cause for canceling a 

 policy. When an ordinary mill or factory adopts the means of safety 

 laid down by the mutual underwriters, it is computed that the outlay 

 is saved in premiums in two years. 



In the foregoing paragraphs a form of scientific underwriting has 

 been briefly described, which has important bearings on the general 

 question of insurance and the reduction of the fire-tax. New England 

 Mutual underwriters have ample scope for their activity in the pur- 

 suit of their business, and are very cautious in pointing any morals to 

 stock-insurance companies. Mutual underwriting is well adapted to 

 the kind of risks it accepts. These are large mills usually isolated. 

 They fall "into comparatively few classes, for which rules for construc- 

 tion and fire-appliances can be readily prescribed. Each passing year 

 finds manufacturers more and more alive to the advantages of the 

 mutual system, the last interest which has begun to adopt it being 

 that of the rubber-factories. 



Mutual underwriting can not be directly applied to the miscella- 



