If a steelpoker is pushed into the fire and left there for a time the handle becomes warm. Heat travels through the metal by a process called conduction. This process is complex. It differs between metals and non-metals. When a metal is heated the free electrons which it contains begin to move faster, i.e., their kinetic energy increases. The hot electrons then drift towards the cooler parts of the metal and at the same time there is a drift of slower-moving (cooler) electrons in the reverse direction. In those substances where no free electrons are present the process of conduction is entirely different. In such cases the heat energy is conveyed by longitudinal waves, similar to sound waves, but of considerably higher frequency. These waves are transmitted in tiny energy packets called 'phonons'. Most metals are good conductors of heat; silver and copper are exceptionally good. On the other hand, substances such as cork, wood, cotton and wool are bad conductors. Both good and bad conductors have their uses.
The best kettles, other than electric kettles, are made of copper, since heat is conducted most rapidly through this metal. The 'bit' of a soldering iron is also made of copper, so that when its tip is cooled through contact with the work, heat is rapidly conducted from the body of the bit to restore the temperature of the tip and maintain it above the melting point of solder. Bad conductors have a very wide application. Beginning with our personal comfort, we prevent loss of heat from ourselves by a covering of poorly conducting material. Textiles are bad conductors of heat, since they are full of tiny pockets of air enclosed by the fibres of the material. Air, in common with all gases, is a very bad conductor of heat. It is usual to say that wool is warmer than cotton. Technically, of course, we imply that it has a lower thermal conductivity than cotton. A stone floor feels cold to the bare feet, but a carpet on the same floor feels warm. This difference arises from the fact that stone is a better conductor of heat than a carpet. To begin with both the stone floor and the carpet are at the same temperature. Since the feet are warmer than either, heat tends to flow from the feet. Stone, being the better conductor, conveys heat away from the feet more rapidly than the carpet. Consequently, the feet feel cold on the stone but warm on the carpet. Precisely the same effect is experienced when handling a garden fork in winter. The iron part of the fork feels cold, but the wooden handle warm.
Loss of heat by conduction through the walls of an oven is reduced by constructing it with double walls. The space between is packed with slag wool or glass fibre. These substances are not only very poor conductors but also have the merit of being non-inflammable. Material of low thermal conductivity used for the purpose of preventing heat loss is called lagging. Another example is the covering of hot-water storage tanks and pipes with a layer of plaster mixed with asbestos or other insulating material. Similarly, cold-water pipes may be lagged with strips of felt or sacking to prevent freezing during very cold weather. Research Transmission of Heat
Fox-hunting is a barbaric blood sport, once a favourite English sport much practised during the autumnal and winter months by the British idle-rich. A traditional pack of foxhounds consisted of from 20 to 60 couples of hounds according to the frequency of the hunting days. These dogs were carefully bred and trained and were under the superintendence of one experienced man called the master, who had the general control of the whole 'field.' Under him were the huntsman, whose duty it was to look after the hounds in their kennels and direct them in the field. The huntsman was directly responsible for the hounds condition and training. Next to him were the whippers-in whose main duty was that of assisting generally the huntsman both in the kennels and in the field. A less important function of the whipper-in was that of urging on lagging hounds.
The night before the hunt, the gamekeeper, calculating on the habits of the fox to leave his burrow or 'earth' in search of food at night, blocked-up all the 'earths' after the foxes have left them. The confused and scared animals were thus forced to seek refuge in neighbouring thickets or other cover, generally near their 'earth', and this fact determined the arrangements of the day's hunting and slaughter.
The huntsmen assembled in the neighbourhood of the stopped 'earth' and drew the neighbouring coverts by throwing off the dogs to search for the fox. The presence of the fox was generally indicated by the whine of some old and experienced hound who had first scented a fox; but a fox may hang or keep within the covert for a long time. The person who first saw the fox leave the covert, break cover as it is called, gave the view-halloo after it had got some little distance, upon which the huntsman collected his hounds and set off in chase followed by the entire field on horse back.
The foxhounds followed almost entirely by scent, the fox being itself perhaps far ahead and out of sight. Wherever, therefore, the scent failed the hounds were said to be at fault, and there was a check until the scent was recovered. When the scent was good most of the hounds own it by giving tongue, and they are were then said to be in full cry.
The rider who was first in at the death (at which the exhausted and terrified fox was literally torn to pieces by the savage hounds) lashed the hounds off and secured the head, feet or pads, and tail or brush of the fox. The midland counties of England, Leicester, Warwick, Yorkshire, etc, were traditionally the most infamous for fox-hunting.
During the 20th century public opposition in Britain to fox-hunting and similarly barbaric pursuits increased, and nature-lovers formed organisations known as hunt-saboteurs to lead false scents and thus sabotage fox hunts, before eventually hunting with dogs was outlawed in the 1990's. Research Fox-Hunting
Abbreviations
Research Transmission of Heat
