Because the volume of the pipe represents the excess of the contraction of the inner walls and the molten lake jointly over that of the outer walls, between the time when the lake begins to ebb and the time when even the axial metal is too firm to be drawn further open by this contraction, the space occupied by blowholes must, by compensating for part of this excess, lessen the size of the pipe, so that the more FIG.
At the side of each of the four scales on the stem of the hydrometer is en r ' graved a set of small numbers indicating the contraction in volume which would be experienced if the requisite amount of water (or spirit) were added to bring the sample tested to the proof strength The hydrometer constructed by Dicas of Liverpool is provided with a sliding scale which FIG.
The blood is probably circulated by the general contraction of the whole animal, since it is very doubtful if there are any intrinsic muscles in the vessel-walls.
A correction has, of course, to be made for the expansion or contraction of the mercury thread if the temperature of reading differs much from that of reversing.
The eyes are closed, the maintenance of posture by active contraction is replaced by the recumbent pose which can be maintained by static action and the mere mechanical consistence of the body, the ears are screened from noise in the quiet chamber, the skin from localized pressure by a soft, yielding couch.
The increments of contraction become, however, less and less, until the succeeding stimuli serve merely to maintain, not to augment, the existing degree of contraction.
The frontier has changed frequently according to the expansion and contraction of the empire under the pressure of political exigency and expedience.
This enormous capacity for expansion and contraction is astonishing if we believe matter to be continuous, but if we imagine air to be made up of little particles separated by relatively large empty spaces the changes in volume are more easily conceivable.
A fire without light, compared to the heat which gathers in a haystack when the hay has been stored before it was properly dry - heat, in short, as an agitation of the particles - is the motive cause of the contraction and dilatations of the heart.
Not only is the respiratory centre stimulated but the cardiac centre is acted upon both directly by the drug and indirectly for a time by the enormous rise in blood pressure due to the contraction of the arterioles all over the body.