# 1911 Encyclopædia Britannica/Safes, Strong-rooms and Vaults

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​SAFES, STRONG-ROOMS AND VAULTS. The term “safe,” whilst really including any receptacle for the secure custody of valuables provided with a lock or other device intended to prevent any person except the owner or some person authorized by him gaining access thereto, has gradually come to be confined to such receptacles when fitted with a vertical door, as distinguished from a lid, and of such a size that they can be moved into position, by the use of proper appliances, in one piece. Such receptacles, when so large as to require that their parts should be assembled in situ, fall under the term “strong-rooms,” or in the case of safe-deposits “vaults,” and when constructed with hinged lids, as distinct from doors, under the terms “cash-box,” “deed-box” and “coffer.” The term “coffer” is probably the most ancient, and in earlier days included, as it still does in France, what are now known as safes. Although it is practically certain that boxes provided with locks or coffers must have followed closely on the development of locks (q.v.) and been in use in ancient Egypt, yet no examples remain to us of earlier date than the middle ages. The earliest examples extant were constructed of hard wood banded with hammered iron, and subsequent development took place rather on artistic than on practical lines up to the time of the introduction of boxes entirely of iron. On the continent of Europe the iron box was developed to a very high standard of artistic beauty and craftsmanship, but with no real increase of security. Several specimens of these coffers supposed to be of 17th-century workmanship are preserved in the museum at Marlborough House. Cast-iron chests seem to have been made in various parts of Great Britain in the early part of the 19th century, but the use of wrought iron was probably confined to London until 1820, or thereabouts, when the trade spread to Wolverhampton. Up to this time no attempt had been made to make coffers fireproof, for though a patent for fireproofing had been taken out in 1801 by Richard Scott, it does not appear to have been used. In 1834, however, a patent was obtained by William Marr for the application of non-conducting linings, followed about four years later by a similar patent in the name of Charles Chubb. The foundation, however, of the modern safe industry was laid by Thomas Milner, originally a tinsmith of Sheffield, who after a few years’ business in Manchester established, in 1830, works at Liverpool for the manufacture of tinplate and sheet iron boxes and who later made plate iron chests or coffers and, probably the earliest, safes about the year 1846. To him is due the modern system of fireproofing, which owes its merit to the use not of non-conductors but of an absorbent material which in the case of fire will be permeated with moisture present in it, either in the form of liquid contained in tubes which burst or otherwise discharge their contents when subjected to heat, or mixed with it as water of crystallization in combination with an inorganic salt. The patent he obtained in 1840 contains the following claim: “Constructing, forming, or manufacturing boxes, safes, or other depositories of an outer case of iron or other metal or material, enclosing one, two, or more inner cases, with spaces or chambers between them, containing an absorbent material or composition, such as porous wood, dust of wood, dust of bones, or similar substances, in which are distributed vessels, pipes or tubes filled with an alkaline solution or any other liquid or matter evolving steam or moisture, the tubes or vessels bursting or otherwise discharging themselves on the exposure of the box or other depository to heat or fire, into the surrounding absorbent matter, which thus pervaded with moisture and rendered difficult of destruction, protects the inner cases or boxes and their contents.” In 1843, Edward Tann, Edward Tann, Junr., and John Tann took out a patent for securing the presence of moisture by means of a chemical salt. In their patent they give preference to alum in combination with Austin’s cement or gypsum, but they also claim“ any non-conductors of heat may be used, and for alum may be substituted sulphate of potash, muriate of ammonia, borax, impure potash, nitrate of soda, soda in cake, pearlash, or any of the known alkalis.” Milner considered this an infringement of his patent of 1840, and in an action before Lord Campbell and a special jury in the Queen’s Bench, on the 3rd of June 1851, a verdict was given upholding his contention.
Fig. 1.
For some years no marked improvements in safes were made, although the manufacture had been taken up in various places by different firms. Safes had, however, been constructed of thicker materials, and some attention had been paid to the more secure attachment of the various parts; also, with the advent of the wrought-iron safe, as distinct from the coffer, the practice had developed of securing the door by a number of bolts operated by a handle and fastening them in the locked position by the lock proper, in order that a small key might be used (Charles Chubb’s patent, 1845).
Concurrently with the increase of strength in safes and probably with the increased value of articles preserved in safes, the skill of the professional thief had also increased, and this went on for some years until the Cornhill burglary of 1865 called general attention to the question. In 1860 a patent was taken out by Samuel Chatwood for a safe constructed of an outer and inner body with the intervening space filled with ferro-manganese or speigeleisen in a molten state, the total thickness being 2 in. (fig. 1). The drilling of conical holes in the inner surface of the outer plate as shown in the figure renders the use of drills of any materials at present known quite inoperative; as the drill, even if it could be made sufficiently hard to pierce the speigeleisen, would on meeting it be bedded in the soft steel and unable to free itself. The construction of such a safe was an expensive matter, and it was not till after the robbery above referred to that he was enabled to sell a single example; it is, however, still in demand for the preservation of diamonds, as probably the only ​ absolutely drill-proof receptacle. This patent is noteworthy as being the only one connected with the lock and safe industry which has been extended by the privy council.
It is about this period (1860–1870), perhaps the most important in the history of safes, that the opening of safes by wedges seems to have become prominent. The effect of wedges was to bend out the side of the safe sufficiently to allow of the insertion of a crowbar between the body and the edge of the door, and various devices were adopted by different makers with the object of resisting this mode of attack. These devices may be placed in three classes: (1) the fixing to the door of studs or projections which, when the door closed, passed into holes or recesses in the frame of the body; (2) the use of bolts hooking into the side framing or entering the bolt holes at an angle; (3) the strengthening of the side framing and of the attachment of the bolts to the outer door-plate. The third of these methods (fig. 2) was patented' by Samuel Chatwood in 1862, and is still very commonly employed. The second method was used by»Chubb and Chatwood, but is not today in general use. The first method was used by all makers of repute, but has now been abandoned, as the increased structural strength of the better class of safes renders such devices unnecessary.
Fig. 2.
To prevent safes from being opened by the drilling of one or two small holes in such positions as to destroy the security of the lock itself, advantage was taken of the improvements in the manufacture of high carbon steel, and even in what is to-day called the “fire-proof” safe a plate of steel which offers considerable resistance to drilling is placed between the outer door plate and the lock.
For many years little advance was made except such as consisted in substituting steel for iron and in general gaining increased strength by the utilization of better materials, although many safes are made and sold to-day which -offer little if any more resistance to Ere and thieves than those of 1860–1870. About 1888 the “solid” safe was introduced. In this the top, bottom and two sides of the safe, together with the flanges at the back only or at both back and front, are bent from a single steel plate (fig. 3). This construction, with solid corners, also illustrated in figs. 1 and 2, only became practicable in consequence of the great improvements which had been made in the quality of steel plates; the credit of its invention formed the subject of litigation, which, however, was not carried to an issue. The abolition of corner Joints, which up to .1888 had been.made~ by dovetailing and by the use of angle irons, had been previously attempted by welding, but the process was abandoned as commercially impracticable.
Fig. 3.
In the early days of the safe industry in America the conditions as far as protection from fire was concerned were entirely different from those obtaining in Great Britain. The timber construction employed in American buildings rendered fires much more fierce, but at the same time of very short duration, not more than an hour or two, To meet this condition of affairs thick, sides of non-conducting materials were more efficacious than the, chambers of steam-generating, materials employed in British construction, but the gradual abandonment of timber and the increasing size of buildings have called for changes in the methods of fire-proofing.
The American “burglar proof” safe, (figs 4) seems to have developed from the fire-proof (fig, 5) Simply by the addition of extra thicknesses of metal, usually alternately hard and soft, without any serious increase of structural strength; this construction, known as the “laminated” or “built up,” offers little resistance to burglars, as the various layers can be separated from one another by the use either of explosives, especially nitroglycerin, or of wedges. In 1890 a commission was appointed by the U.S.A. government to report upon the strong-rooms or vaults of the treasury at Washington; and their report was presented in September 1893. This commission) based their conclusions on experiments conducted in their presence, as well as on well-authenticated experiments performed by safe-makers on their own and other makers? productions, and they found
| Fig. 4.—American Burglar-proof Construction. | Fig. 5.—American Fire-proof Safe. |
that, with the single exception of the Corliss safe, all the safes which came under their notice—and these comprised all the best-known American makes—could be opened by burglars by ​drilling, by the use of explosives, and by the use of wedges and similar well-known tools. This Corliss safe consists of a spherical shell of cast iron several inches thick and with its exterior hardened by “chilling.” It is fitted with a ground-in door rotating concentrically with the shell and internally. The spherical form and great thickness render the useful space in the interior very small and of inconvenient shape.
The requirements of a modern safe may be briefly summarized.
In fire- and thief-proof safes, the body and door must be constructed of sufficient thickness, and the joints as well as the attachment of the door to the body frame of sufficient strength, to remain uninjured by a fall from the highest position in which the safe may be placed to the basement, or by the impact of any debris, coping stones, girders, &c., falling from the highest part of the building to the basement. The space between the outer body and the inner casing must be properly charged with a steam-generating mixture in sufficient quantity to keep the interior of the safe moist for the whole time during which it may be subjected to heat in the case of a fire. The same requirements must be satisfied in burglar-proof safes. In addition, the body and door must be of such material and of such thickness that it is impossible to cut a sufficiently large hole to extract the contents, and so constructed that they cannot be dismembered; the framing and attachment of the bolts to the door must be able to resist the action of wedges or forcing screws; the vital parts of the lock and bolt-work must be further protected so that it is impossible to attack them by drilling, and this protection must not be liable to be destroyed by the action of heat; the lock itself must not be capable of having its security destroyed by the explosion of the largest quantity of explosive which can be inserted. If these conditions are satisfied there is little fear that the oxy-acetylene blowpipe, the electric arc or the use of the higher explosives can be made effective. The amount of protection required to meet the above conditions must, in each case, depend on what tools it is reasonable to anticipate may be employed by the burglar and the maximum time which he may have at his disposal. The use of high explosives has become a more frequent method of attack by burglars in Great Britain, but where the safes have been of the best quality, of solid construction and good workmanship, this means of attack has been rendered ineffective.
Strong-rooms and Vaults.—It is not hard to imagine that the use of strong-rooms was much earlier than that of safes; in fact, there can be no doubt that masonry rooms provided with heavy wooden doors secured by locks were in use in ancient Egypt, and that the development of strong-room doors attached to masonry rooms followed that of the old coffers very closely. No exact date can be obtained as to the introduction of what we may call modern strong-rooms, but it is only reasonable to suppose that, where larger quantities of valuables had to be preserved than a safe would conveniently hold, a safe-door of larger dimensions would be made and attached to a masonry or brick room. The next step would be the discovery that the walls of such a room offered little protection against even unskilled violence, and the lining of the room with metal would immediately follow; the door frame, as a matter of course, being attached to the plating. Strong-rooms of this construction are in common use to-day by
Fig. 6.
banks and other institutions; and, as with safes, so with strong-rooms, development has taken place in the direction of increasing the thickness and the structural strength as well as in the application of superior locking devices (see Locks).
This increase of structural strength has been carried along somewhat different lines by different makers in Great Britain and along still more diverse lines in America. Masonry or brickwork alone is now rarely relied on for the protection of goods of any great value; concrete, however, reinforced by old railway metals imbedded therein and sometimes connected together to form, as it were, a cage, is in use. Railway metals attached to steel plates and also bedded in concrete are very largely employed. Thick plates of steel and latterly of manganese and other special, steels are also in common use. Various forms of strong-room walls are illustrated in fig. 6.
Usually a strong-room is provided with an open-work gate or ​“grille” as well as a door, so that the contents may be protected by the gate during business hours without preventing the free access of air; they are usually also fitted for convenient subdivision. Safe deposit vaults do not differ in any way from strong-rooms, except that they are fitted up with small safes or integers provided with special locks, so that the renter can gain access to his own integer only, and this only with the assistance of a custodian.
Many electrical devices have been introduced, having for their object the giving of an alarm when strong-rooms or safes are improperly approached or tampered with. Most of these devices were quite useless, as they could at once be rendered inoperative; but though others displayed greater ingenuity, it is very questionable whether they are of any real utility, and they have not remained in common use. Where the value known to be contained in a strong-room is sufficiently great, an attack by tunnelling must be specially guarded against, and as in this form of attack the time which may be devoted to preparing for the actual breaking through is practically unlimited, the use of some device which will give warning of any such attack before the floor of the strong-room itself is reached is of very great importance. Probably the best of such devices, and one which is in practical use, consists of a network of small pipes, laid in concrete below the floor, and filled with glycerin or other liquid. To this network a mercury manometer is connected. If any breach is made in the pipe system, a leakage takes place, causing an alteration in the level of the mercury in the manometer, which may, if desired, be arranged to ring a bell. The manometer should in any case be observed regularly on the opening of the strong-room.  (A. B. Ch.)