Quantity in any one

store.

the sewers, causing great damage. Again, at Anderston Quay, Glasgow, on January 16, 1897, quantities of burning oil escaped and ran down the streets, damaging buildings and property. Underground tanks are the safest in this respect, as escape of the oil cannot occur, unless it is displaced by water intended to extinguish the fire, as was the case in an accident which occurred at Notting Hill on March 5, 1890. But where underground tanks are installed, the greatest care must be taken to prevent the oil percolating through the soil to a sewer or to some building, in the event of a leak occurring; and, whereas leakage from an overground tank is readily observed, it is difficult to detect escape where the tank is sunk in the ground.

The quantity of petroleum which should be kept in any one store should depend on the method of keeping, and on the distances from "protected works." In the Inflaminable Liquids Bill, 1891, "protected works" were defined as buildings in which persons dwell or assemble, docks, wharves, timber-yards, other petroleum stores, and any other place which the local authority might require to be so treated. In Appendix XVI. will be found a notice of the distances which should be maintained whenever possible for various quantities and methods of keeping. Where petroleum is kept in a house it should never be stored in such a situation as, in case of fire, to prevent the escape of persons in the building. Three persons were burnt to death in the accident at Lambeth quoted above, their escape having been cut off by the burning oil, which was stored underneath the staircase. In general, the oil should be placed in the basement or outside the house, and in the case of shops it should be drawn to the place where it is wanted by a pump connected with the tank or barrel by means of a lead pipe.

Petroleum should never be kept or conveyed with

kept or

with

any explosive. It was the neglect of this rather obvious Petroleum precaution which led to the disastrous explosion on the not to be Regent's Park Canal on October 2, 1874. In that conveyed instance gunpowder and petroleum spirit were being explosives. conveyed in the same barge, and the vapour from the spirit found its way into the cabin where a fire was burning. The keeping of petroleum near explosives is prohibited by the Explosives Act, but notwithstanding this, it sometimes happens that a person ignorantly stores the two substances together, under the mistaken belief that in dealing with two dangerous things it is better to consolidate the risk.

veyance.

The precautions which have been enumerated refer Precautions mainly to the storage of petroleum; but many of them in conapply with equal force to conveyance. Thus the dangers of ignition and of leakage are as great, or even greater, when petroleum is being conveyed as when it is being kept in a place of storage. Until recently, accidents in the conveyance of petroleum by sea have been both serious and numerous; but it is to be hoped that as the proper construction of ships for this purpose is now better understood, and more rigorous attention. is paid to harbour by-laws, accidents of this class will become less frequent. It has been pointed out in a previous chapter that harbour authorities have no power to make by-laws governing the shipment of petroleum; but this in no way relieves persons from the responsibility of adopting the same precautions in shipping as are enjoined in the landing of petroleum. (See Appendix V.)

the holds of

Special care must always be taken in cleansing the Cleansing holds or tanks of vessels which have carried petroleum petroleum from all oil and vapour before a naked light is admitted, ships. or before repairs are carried out. The best method of doing this in the case of tank-steamers is first to fill the tank up with water so as to float out all remnant

of the oil, and then to pump out and thoroughly dry the tank. A powerful ventilating fan should then be applied, and should be kept working during the whole time men are working in the tank. Modern petroleum ships are usually fitted with a suitable fan for this purpose, but in some vessels a steam ejector is used for the purpose. Ordinary windsails do not furnish a very efficient means of cleansing a tank, and should not be relied on unless the conditions are exceptionally favourable for their use. Whatever the method of ventilation employed, the operation of cleansing is much assisted by injecting steam into the tank so as to warm the interior. That these precautions are necessary with vessels which have carried refined oil, as well as with those which have carried crude oil or spirit, was shown by the explosion which occurred in the s.s. Petriana on December 26, 1886, during repairs. This vessel had discharged a cargo of oil of a flash-point of 79° F. (Abel), and the tanks, having undergone repair, were being tested when a rapid ignition of the atmosphere in one of the tanks occurred, which caused the death of ten persons. In this case a spray of oil had in all probability been forced into the tank, but in the chapter on flash-point it has been pointed out that, under certain conditions, an explosive mixture of vapour and air may be formed by petroleum oil when at a temperature considerably below its flashpoint.

It must be remembered that when a tank which has contained petroleum spirit is filled with water for the purpose of cleansing, a considerable quantity of vapour will be driven out; and in certain conditions of the weather this may tend to flow to some point where ignition could take place. Not only therefore must the requirement of the harbour by-law that no fire or light be on the vessel be strictly observed, but care

must also be taken that the position of the vessel at the time of cleansing is such that no danger can arise from neighbouring vessels or from any external source of ignition.

Of accidents in conveyance by road and rail there Conveyance have not been a great number in this country, nor, by road and with one exception, have they been attended by very serious consequences. The exception referred to is the accident at Abergele on August 20, 1868, when the Irish mail ran into a goods train carrying about fifty barrels of paraffin oil which was ignited, and thirtythree persons were burnt to death. It is doubtful whether any precaution would prevent an accident of this description. Where a train carrying petroleum meets with a serious collision, the petroleum will almost inevitably be spilt, and a fire will be very likely to ensue. In general, the vessels in which petroleum is conveyed should be of such substantial construction as to withstand rough usage, and even a mild collision, without allowing their contents to escape. A slight collision which occurred in shunting on the sidings of the Great Northern Railway on August 16, 1889, caused the breakage of some puncheons or large petroleum casks of insufficient strength containing mineral naphtha, and the spirit catching fire, the driver and fireman were burnt to death.

An important precaution in the conveyance of Over-filling petroleum is to avoid over-filling the vessel in which it of vessels. is contained. The expansion of the liquid on rise of temperature, especially in the case of spirit, is considerable; and unless a sufficient air-space is left, this expansion will be liable to burst or strain even the strongest vessels. The amount of air-space which should be left ought never to be less than 5 per cent. of the total capacity of the vessel, and it would be better always to allow 7 per cent.

Petroleum barrels to be

covered in

Petroleum spirit in barrels, when conveyed in open trucks or lorries, should be covered by a tarpaulin to conveyance. avoid the danger of ignition, in case of leakage, by a spark from without.

Drivers of waggons carrying petroleum spirit should not be allowed to smoke or even to carry matches, and such waggons should only travel during the hours of daylight. A driver should be in constant attendance on his waggon at all times when the latter is on a public thoroughfare, and should take every precaution to prevent mischievous persons approaching his vehicle, especially when leakage or spilling of the spirit may have occurred. In an accident which occurred at Hackney on January 6, 1880, a van loaded with petroleum spirit caught fire in the street from some cause which was not ascertained, and the burning liquid escaped, to the great danger of surrounding houses, several of which were scorched. Again, on December 20, 1898, in Great Russell Street, a man deliberately threw a lighted match into some spirit which had been spilt from a cart, with the result that the cart and all the naphtha were destroyed.

Fortunately, accidents in the conveyance of petroleum by canal have not been numerous. The Regent's Park explosion originated in the ignition of benzoline vapour, but in that instance a large quantity of gunpowder was also present. The vapour penetrated into the cabin of the barge, and was there by some means ignited. As it would be impossible in canal barges of ordinary construction absolutely to prevent such penetration of vapour, all fires and lights should be excluded from barges carrying petroleum spirit. As in the case of conveyance by road, petroleum, whether oil or spirit, should be covered over so as to protect it from ignition from without.

The hawking of petroleum spirit is provided for by