126 



EX PARTE EXPLOSION. 



during the whole of that ran:e, 5ts bulk precisely 

 corresponded with the bulk of water the same iium- 

 l>er of degrees above 42. 5. The prodigious force 

 with which water expands in the act of freezing, is 

 shown by glass bottles filled witli water, which are 

 commonly broken in pieces when the water freezes. 

 A brass globe, whose cavity is an inch in diameter, 

 may be burst by filling it with water and freezing it ; 

 and the force necessary for this eflect is 27,720 

 pounds weight. The expansive force of freezing 

 water may be explained by supposing it the conse- 

 quence of a tendency which water, in consolidating, 

 is observed to have to arrange its particles in one 

 determinate manner, so as to form prismatic crystals, 

 crossing each other at angles of GO" and 120. The 

 force with which they arrange themselves in this 

 manner must be enormous, since it enables small 

 quantities of water to overcome so great mechanical 

 pressures. This observation is conspicuously illus- 

 trated by observing the crystals of ice on a piece of 

 water exposed to the action of the air in frosty wea- 

 ther ; or upon a pane of glass in a window of a room 

 without a tire, at the same season. Various methods 

 have been tried to ascertain the specific gravity of 

 ice at 32; that which succeeded best was to dilute 

 spirits of wine with water till a mass of solid ice put 

 into it remained in any part of the liquid without 

 either sinking or rising. The specific gravity of such 

 a liquid is 0.92, which, of course, is the specific gra- 

 vity of ice, supposing the specific gravity of water at 

 60 to be 1. This is an expansion much greater 

 than water experiences even when heated to 212, 

 its boiling point. We see from this that water, 

 when converted into ice, no longer observes that 

 equable expansion measured by Dalton, but under- 

 goes a very rapid and considerable augmentation of 

 bulk. 



EX PARTE ; a term used in the court of chan- 

 cery, when a commission is taken out and executed 

 by one side or party only, upon the other party's ne- 

 glecting or refusing to join therein. 



EXPECTATION, in the doctrine of chances, is 

 the value of any prospect of prize or property de- 

 pending upon the happening of some uncertain event, 

 the value of which, in all cases, is equal to the 

 whole sum multiplied by the probability that the 

 event on which it depends may happen. 



Expectation, in the doctrine of life annuities, de- 

 notes the time which a person of a given age may 

 expect to live. Simpson's table of the expectation 

 of life, in London, is as follows : 



From this table, the expectation of life, at any 

 age, is found, on inspection, thus : a person of 20 

 years of age has an expectation of living 28.9 years ; 

 nnd ir the same manner may be found the expecta- 

 tion at any other age. See Annuity. 



EXPECTORANTS, in pharmacy; medicines 



which promote expectoration. Such are the stimu- 

 lating gums and resins, squills, &c. 



EXPECTORATION ; the act of evacuating, or 

 bringing up phlegm, or other matters, out of the 

 trachea and lungs, by coughing, &c. 



EXPEDITIONS TO THE NORTH POLE. Sea 

 North Pole. 



EXPERIMENTAL PHILOSOPHY is that which 

 deduces the laws of nature, the properties and 

 powers of bodies, and their actions upon each other, 

 from sensible experiments and observations. In our 

 inquiries into nature, we are to be guided by those 

 rules and maxims which are found genuine, and con- 

 sonant to a just method of physical reasoning ; and 

 these rules are, by Sir Isaac Newton, reckoned four, 

 viz. 1 . more causes of natural things are not to be 

 admitted than are true, and sufficient to explain the 

 phenomena ; for nature is simple, and does nothing 

 in vain. 2. Therefore, of natural effects of the 

 same kind, the same causes are to be assigned, as far 

 as it can be done ; as of respiration in man and 

 beasts, of the descent of stones in Europe and Ameri- 

 ca, of light in a culinary fire and in the sun, and of 

 the reflection of light in the earth and the other 

 planets. 3. The qualities of natural bodies, which 

 cannot be increased or diminished, and agree to all 

 bodies, on which experiments can be made, are to 

 be reckoned as the qualities of all bodies whatever ; 

 thus, because extension, divisibility, hardness, impene- 

 trability, mobility, the vis inertice, and gravity, are 

 found in all bodies under our inspection, we may 

 conclude that they belong to all bodies whatever, 

 and are the original and universal properties of 

 them. 4. In experimental philosophy, propositions 

 collected from the phenomena by induction, are to 

 be deemed (notwithstanding contrary hypotheses) 

 either exactly, or very nearly true, till other pheno- 

 mena occur, by which they may be rendered more 

 accurate, or liable to exception. This ought to be 

 done, lest arguments of induction should be destroyed 

 by hypotheses, and logical series be superseded by 

 conjectures. 



EXPLORATOR ; a contrivance, invented by 

 Beccaria, consisting of a wire, whose insulated ends, 

 provided with knobs of tin, are fastened to a pole 

 over the chimney, or to the top of a tree. From this 

 wire, another leads into a chamber, through a glass 

 tube, covered with sealing-wax, communicating, in 

 the chamber, with an electrometer, by which the 

 electricity of the air may be daily observed. 



EXPLOSION, in natural philosophy; a sudden 

 and violent expansion of an aerial or other elastic 

 fluid, by which it instantly throws off any obstacle iu 

 its way. Explosion differs from expansion in this, 

 that the latter is a gradual power, acting uniformly 

 for some time, whereas the former is momentary. 

 The expansions of solid substances do not terminate 

 in violent explosions, on account of their slowness, 

 and the small space through which the expanding 

 substance moves. Thus we find, that, though wedges 

 of wood, when wetted, will cleave solid blocks of 

 stone, they never throw them to any distance, as gun 

 powder does. On the other hand, it is seldom that 

 the expansion of any elastic fluid bursts a solid sub- 

 stance, without throwing the fragments of it to a con- 

 siderable distance. The reasons of this may be com- 

 prised in these particulars : 1. The immense velocity 

 with which the aerial fluids expand, when affected by 

 a considerable degree of heat. 2. Their celerity in 

 acquiring heat, and being affected by it, which is 

 much superior to that of solid substances. Thus air, 

 heated as much as iron when brought to a white heat, 

 is expanded to four times its bulk ; but the metal 

 itself svill not be expanded the 500th part of that 

 space. In the case of gunpowder, the velocity with 



