A CHAPTER IN FIRE INSURANCE. 761 



4. Elevators, stairways, and other openings from floor to floor 

 should be cut off by properly constructed hatches, doors, or other 

 means, automatic in action, if possible. 



5. Openings in party-walls and exposed windows should be pro- 

 tected by wooden doors or shutters, covered with tin, preferably 

 self-acting, 



6. Rooms in which special danger exists should be plastered on 

 wire lathing close to the surface of the ceiling, and following the 

 line of the timbers. All iron posts in exposed places, or iron or stone 

 posts, on which the safety of a building greatly depends, should be 

 protected from fire, either with wood or tin, or by wire lath and plas- 



tenng. 



Of materials for walls, brick is best, and sandstone next best. 

 Limestone calcines and crumbles at high temperatures, and granite 

 breaks and cracks most dangerously. When gas is used in lighting a 

 mill, it is proper to have a controlling valve external to the mill, so as 

 to cut off the supply in case of fire. Sometimes gas is carbureted 

 with gasoline, in which case, fifteen minutes before a mill ceases work 

 at night, the uncarbureted gas is alone permitted to be used, so as to 

 take up any liquid deposited in the pipes. When electric lighting is 

 adopted, approved rules for its installation and use must be observed. 



Whenever possible, mills should not exceed one story in height. 

 When so constructed, they can be better lighted than lofty buildings, 

 and they are much less liable to costly vibration. This latter source 

 of loss in a mill four or five stories in height may absorb a fifth of the 

 motive power. A one-story mill, in case of fire, is much more safe and 

 manageable than a lofty structure. It is pleasant to find so potent 

 economic arguments against the tendency which, in recent years, has 

 piled up factories so high, and crowded them together so closely. 



Steam-pipes, for heating purposes, have been found quite as effect- 

 ive when suspended from the ceiling as when placed upon the floor ; 

 while, in the former case, they do not fm-nish lodgment to cotton- 

 waste, paper, shavings, and other combustible material. Similar refuse 

 is apt to gather dangerously about a steam-pipe rising through a floor 

 — the means of safety here being its inclosure in a cast-iron shield of 

 conical form. Steam-pipes require careful protection from contact of 

 inflammable substances. Of non-conducting covering materials, asbes- 

 tus, hair-felt, cork, fossil-meal, magnesia, and rice-chaff are the best. 



The rules hei'e presented in mere outline are given in detail by 

 Mr. C. J. H. Woodbury, inspector of the Boston Manufacturers' 

 Mutual Insurance Company, in his work on the " Fire Protection of 

 Mills." They are the outcome of the long and varied experience of 

 the Mutual Companies of New England. Of these companies, the one 

 I have just mentioned is the foremost, and I am indebted to its presi- 

 dent, Mr. Edward Atkinson, for data included in this sketch. From 

 an analysis of the causes of fires in which his company was interested 



