Of fire

The superior region of the Air, next to the moon, is pure without being igneous as has been long taught in the schools, according to the opinion of some of the ancients. Its purity is contaminated by none of the vapours which rise from the lower region. 

The middle region receives the most subtle sulphurous exhalation, free from the gross vapours. They wander in it, and are set on fire from time to time by their movements and the different shocks which they undergo among themselves. These are the different meteors which we perceive in the middle region. 

Some of the ancients placed Fire as a fourth Element, in the highest region of the Air, because they regarded it as the lightest and most subtle. But the Fire of Nature does not differ from the Celestial Fire this is why Moses makes no mention of it in Genesis, because he had said that Light was created on the first day. 

The fire which we use ordinarily is partly natural and partly artificial. The Creator has placed in the sun an igneous spirit, the principle of movement and of gentle heat, such as is necessary to Nature for 

It is placed in the Moist Radical as its proper seat. With animals it seems to have established its chief domicile in the heart, which communicates it to all parts, as the sun does to all the Universe. 

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Carbon disulphide should never be used if any alternative solvent is available, as it has a dangerously low flash-point, and its vapours form exceedingly explosive mixtures with air. Ether as a solvent for recrystallisation is much safer than carbon disulphide, but again should be avoided whenever possible, partly on account of the danger of fires, and partly because the filtered solution tends to creep up the walls of the containing vessel and there deposit solid matter by complete evaporation instead of preferential crystallisation. 

The ethereal extracts are then united, dried with a suitable drying agent and filtered. The filtrate is then cautiously distilled, the ether being first distilled and finally the organic compound if volatile if the compound is solid, the crude residue is purified by recrystallisation. Very great care must be taken on all occasions when ether is distilled because of the risk of fire or of an explosion full experimental details for this operation are given, both on p. 8o (Preparation of Ether) and on p. 164 (Pre-... 

For temperatures up to 100°, a water bath or steam bath is generally employed. The simplest form is a beaker or an enamelled iron vessel mounted on a suitable stand water is placed in the vessel, which is heated by means of a flame. This arrangement may be used for non-inflammable liquids or for refluxing liquids of low boiling point. Since numerous liquids of low boiling point are highly inflammable, the presence of a naked flame will introduce considerable risk of fire. For such liquids a steam bath or an electrically-heated water bath, provided with a constant-level device, must be used. If the laboratory is equipped with a... 

Beginnera may prefer to fit the flask with a reflux condenser and thus considerably reduce the danger of fire. 

Stahl subsequently renamed the terra pingnis phlogiston, the motion of fire (or heat), the essential element of all combnstible materials. Thns the phlogiston theory was born to explain all combnstion and was widely accepted for most of the eighteenth centnry by, among others, such luminaries of chemistry as Joseph Priestley. 

Flash points and autoignition temperatures are given in Table 11. The vapor can travel along the ground to an ignition source. In the event of fire, foam, carbon dioxide, and dry chemical are preferred extinguishers. The lower and upper explosion limits are 1% and 7%. 

The transparency of methanol flames is usually a safety advantage in racing. In the event of fires, drivers have some visibiUty and the lower heat release rate of methanol provides less danger for drivers, pit crews, and spectators. 

Fig. 5. Two-stage light gas gun showing the piston and H projectile where M = propellant charge and 1 = light gas (a), before firing (b), after firing propellant charge (c), as piston nears necked-down mouth of the launch tube (d), after completion of firing cycle. Piston is removed from neck of launch...

The assessment of the contribution of a product to the fire severity and the resulting hazard to people and property combines appropriate product flammabihty data, descriptions of the building and occupants, and computer software that includes the dynamics and chemistry of fires. This type of assessment offers benefits not available from stand-alone test methods quantitative appraisal of the incremental impact on fire safety of changes in a product appraisal of the use of a given material in a number of products and appraisal of the differing impacts of a product in different buildings and occupancies. One method, HAZARD I (11), has been used to determine that several commonly used fire-retardant—polymer systems reduced the overall fire hazard compared to similar nonfire retarded formulations (12). 

Flame-retardant additives are capable of significant reduction in the ha2ard from unwanted fires, and techniques are now available to quantify these improvements. Combined with an understanding of fire-retardant mechanisms, polymer-retardant interactions, and reuse technology, formulations optimi2ed for pubHc benefit and manufacturing practicaUty can be selected. 

W. P. Me3.de, A First Pass at Computing the Cost of Fire in a Modem Society, The Herndon Group, Inc., Chapel Hill, N.C., 1991. 

V. Babrauskas, SFPE Technology Report 84-10, Society of Fire Protection Engineers, Boston, Mass., 1984. 

V. Babrauskas and co-workers. Fire Hazard Comparison of Fire-FetardedandISion-Fire-FetardedProducts, NBS Special Pubhcation 749, National Bureau of Standards, Gaithersburg, Md., 1987. 

J. W. Lyons, The Chemistry and Uses of Fire Fetardants, Wiley-Interscience, New York, 1970, Chapt. 5. 

One problem associated with discussing flame retardants is the lack of a clear, uniform definition of flammabiHty. Hence, no clear, uniform definition of decreased flammabiHty exists. The latest American Society for Testing and Materials (ASTM) compilation of fire tests Hsts over one hundred methods for assessing the flammabiHty of materials (2). These range in severity from small-scale measures of the ignitabiHty of a material to actual testing in a full-scale fire. Several of the most common tests used on plastics are summarized in Table 1. 

Reduction of Fire Hazard Using Fire Retardant Chemicals, Fire Retardant Chemicals Association, Lancaster, Pa., 1989. 

Handbook of Fire Retardant Coatings and Fire Testing Services, Technomic, Lancaster, Pa., 1990. 

The weight and constmction of the fabric affect its burning rate and ease of ignition. Lightweight, loose-weave fabrics bum much faster than heavier weight fabrics therefore, a higher weight add-on of fire retardant is needed to impart adequate flame resistance. 

The most extensive body of tests are provided under the auspices of ASTM Standard methods. Specific ASTM test designations and descriptions are available (48). The other compendium of fire-retardant tests are contained ia Federal Test Method Standards 191A (49). 

Natural gas and its combustion properties appear to have been known since early times (2). Some early temples of worship were located in areas where gas was seeping from the ground or from springs, and it is reported that Julius Caesar saw a phenomenon called the "burning spring" near Grenoble, France. Gas wells were drilled in Japan as early as 615 AD and in 900 AD the Chinese employed bamboo tubes to transport natural gas to their salt works, where the heat was used to evaporate water from salt brine. The existence of natural gas in the United States was reported by early setders who observed gas seeps and columns of fire in the Ohio Valley and the Appalachian area in 1775 (3). 

Fire-Resistant Hydraulic Fluids. The four classifications of fire-resistant hydrauHc fluids are Hsted below (7). Three of the four groups are fire resistant because they contain a significant amount of water which provides cooling and blanketing of the combustible materials. 

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