Perhaps a more curious case, in which an unexpected use was made of the register, occurred at the time of the terrible Abergele accident to the Irish mail train. Mr. Lund, a passenger in the train, was killed, but nothing could at first be found upon him as a likely means of identification. He happened, however, to have a registered chain, and upon telegraphing to my firm the number on the label his name and address were at once discovered.
It may be of use to add a few particulars respecting the amount of coin that can be stowed in a certain space, in order that it may be easily calculated how much any safe will hold. The Bank of England reckoning for the room required to stow away gold coin in bags is 79 cubic inches to 1,000l. One cubic foot will contain no less than 21,875l. In order to allow a slight margin and to be on the right side, it may be considered that 80 cubic inches will contain 1,000l. in bags of sovereigns.
For silver coin the Bank reckoning is that 157 cubic inches will hold 100l., and that one cubic foot will hold 1,235l. in bags. To allow a margin as before, it may be said that 160 cubic inches contain 100l. in silver coin.
CHAPTER IV.
SAFES AGAINST FIRE.
PERHAPS there is a greater demand for fire-resisting than for thief-resisting safes, and certainly it is in the former character that they are most often put to the test. The consideration, therefore, of what is the best form of construction to cope with fire is most important; while it is also a much simpler matter than when strength against thieves is required.
In fire we have an element whose character is known, and which cannot attack us in some new way for which we are not fully prepared. All that it can do to a safe is to exercise upon it a certain heat, the intensity of which may be pretty nearly determined, and which cannot in actual practice last beyond a certain time. Probably heat that will melt iron in a large mass is seldom produced in the burning of an ordinary dwelling-house; but in a warehouse with inflammable contents such fierce heat often exists, so that a safe should be proof against it for two or three hours. Unless a safe were very bulky it could not well preserve its contents without any damage for a much longer time; and indeed it is not necessary, for no safe is very likely to be exposed to an intense all-round fire longer than three hours; by that time it will either have fallen into rubbish, or the débris from above will have covered it in, and protected it from immediate contact with the fire. It will be seen from this that it is advisable not to build a safe partially into a wall or recess; the chances being that it will be kept in its place long enough to have the full force of the fire expended upon its exposed portion, and then fall a greater distance and upon harder material than if it had fallen when the wooden floor first gave way.
The first quality that a fire-resisting safe should possess is strength in its construction sufficient to prevent its being damaged by a heavy fall, or sustaining injury through the plates warping from heat. This cannot be obtained unless the outer plates are at least a quarter of an inch thick (or upwards, in big safes), strongly joined at all the edges by stout angle-irons well rivetted to them. Other and more expensive methods are used to join the edges, and are doubtless better than the foregoing; but this is at once a cheap, effectual, and most generally used method.
Secondly, it is essential to make the safe as nearly airtight as possible, to do which it is only necessary that the door should fit very closely at its edges, and that its inside face touches at every possible point the interior of the safe.
The third thing to be considered is the fire-proofing—the most important feature of the safe. Almost everything that one can think of has been either proposed or used for proofing—water, wood, paper, plaster-of-Paris, chemicals of all sorts, and many other things besides. But of all these what may be termed a combination of water and wood, in the forms of alum and sawdust, has been most extensively used.
There are two walls of wrought iron in the safe, and the intervening space has to be filled with a fire-resisting material, which may be either of a refractory nature, such as fire-clay, sand, or any other practically infusible slow conductor of heat; or it may be an absorbent substance containing chemicals that will evolve moisture when heated. The former of these two methods is now seldom used except by makers of cheap common safes, who sometimes use clay, ashes, or mould. The evaporating system is generally adopted, and as a rule the absorbent material is common sawdust, with which is mixed ordinary alum, the water of crystallisation in the alum being gradually parted with under the continued heat generated by fire. Mahogany sawdust is preferred, as being less combustible than that of white woods.