COL them , anil, while tends to dissipate their sub- id conch i, and strengthens to ir mutual cohesion. Hui, though cold thus app iars, by ■rets, to ! more than the absence or privation of hint, .;. darkness is only the
- of light, vet colli is probably
I erf another quality, which lias induced man} to consider it as a substance of a pi culiar nature. It ! known, that when a conti- nuance of cold has contracted and tensed bodies to a certain de- gree, if then its power be mere instead of progressively lessening their bulk, it enlarges and expands , so that extreme cold, htat, swells the substance into which it enters. Thus fluids sc n- sibly contract in a cold tempera- ture, till the moment they begin to freeze, when they immediately dilate, and occupr more space than they possessed while in a state of fluidity. Hence, liquor frozen to i a close cask, is often known to burst the vessel : when ice is broke on a pond, it swims upon the surface ; a certain proof of its being lighter, or of a larger bulk, than an equal quantity of water. This dilatation of fluids, however, is probably owing to a cause very different from that of excessive coid alone ; because the power of freezing may be arti- ficially increased, while the intense- ness of the cold receives no consi- derable addition ; and, on the con- trary, a substance capable of melt- ing ice, will increase the degree of its coldness. Thus, for instance, sal ammoniac mixed with pounded ice, or with snow, melts either of them into water ; and increases their cold to a surprizing degree, as is obvious from the effects of COL |;, thi-. mixture, in sinking tin- till r- mometer; Hence the freezing of fluids cannot be < ntir. ly consider- ed as the result of cold, hut of some unknown property either in the air or water, which thus mixes with the body, and tor a time de- stroys its fluidity. We cannot, in this place, enter into farther particu- lars relative to this curious subject j but .as there have lately been in- vented several methods of convert- ing water into ice, which may be of service in domestic economy, Ave s'lall communicate the mosl and least expensive processes of this kind, under the article Ice. COLIC, a disease attended with wandering pain in the bowels, and rumbling noise ; both abating on the expulsion of wind: there is a slight degree of thirst ; the pulse is scarcely affected, and the pain is not increased by pressure, as is the case in inflammations. This complaint may arise from a great variety of causes; the prin- cipal of which are, 1 . Flatulency ; 2. Tough, pituitous humours, clog- gins: the intestines; 3. Worms; 4. Bile; 5. The Piles; 6. Hyste- rics; 7. Acrid food or drink; 8. The inhalation of vapours arising from the decomposition of lead ; 9. Rheumatism; 10. The use of sour wines and cyder; 11. The gout; 12. A sudden catarrh; 13. An acid generated in the first pas- sages; 14. Obstructions in the in- testinal canal; and, 15. Poisonous substances introduced into the sto- mach. Consistently with our plan, we shall but briefly treat, here, of those colics which originate from the 2d, 7th, 10th, and 13th of the causes before enumerated ; as the reader will find the other species discussed under their respective heads of the alphabet,
