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puted from thefe numbers, comes out fomething more than | in the preceding inftance, amounting to between 1 1 and | 12 pounds avoirdupoife : whence, according to thefe expe- ; riments, the reft/ling power of the air to fwift motions is greater than in flow ones, in a ratio which approaches nearer to the ratio of 3 to 1, than in the preceding expe- riments.

Next, to examine this refiftame in fmaller velocities, the pendulum being placed at 25 feet distance, was fired at five times, and the mean velocity with which the ball impinged was 3180 feet in 1". Then removing the pendulum to the distance of 250 feet, the medium velocity of five fhot at this distance, was 950 feet in r ; whence the ball, in patting through 225 feet of air, loft a velocity of 230 feet in 1", and as it patted through that interval in about -rV of 1", the refinance to the middle velocity will come out to be near 33!; times the gravity of the ball, or 2 lb. 10 oz. avoirdu- poife. Now the refi/tance to the fame velocity, according to the laws obferved in flower motions, amounts to iV of the fame quantity; whence in a velocity of 1065 feet in (the medium of 11 80 and 950) the rejijiing power of the air Is augmented in no greater proportion than of n to 7 ; whereas in 2*> C nter decrees of velocity, as before, it amounted very near to the ratio or 3 to I. That this refijling power of the air to fwift motions, is very fenfibly increafed beyond what Sir Ifaac's theory for flow motions makes it, feenis hence to be evident. It be- ing, as has been faid, in mufket, or cannon fhot, with their full charge of powder, near three times the quantity assigned by that theory.

The reft/lance of a bullet of three quarters of an inch dia- meter, moving in air with a velocity of 1670 feet in 1", amounting, as we faid, to 10 lb. the refiftame of a cannon ball of 241b. fired with its full charge of powder, and there- by moving with a velocity of 1650 feet in 1" (which fcarce differs from the other. See Gunnery, Append.) may hence be determined. For the velocity of the cannon ball being near the fame as the mufket bullet, and its furfacc above 54 times greater, it follows, that the refijlance on the can- non ball will amount to more than 540 lb. which is near 23 times its own weight. And from hence it appears how rafh and erroneous the opinion of thofe is, who neglect the confideration of the refijlance of the air as of no import- ance in the doctrine of projectiles. See Projectile.

RESPIRATION (Cycl)— The alternate motion of the thorax and lungs in refpiration is evident, but it is not eafy to determine the mechanifm by which thefe motions are per- formed. Dr. Martin thinks this has not been accounted for in a fatisfactory manner, either by Swammerdam, Bo- relli, Ballivi, Pitcairn, or Boerhaave, and has given us an elTay on this fubject in the Medic. Eff. Edinb. Vol. 1. Art. 12.

Dr. Hoadley fl endeavours to prove, that the external inter- coital mufcies ferve for tnfpiration, while the internal inter - coftals are their antagonists, deprefHng their ribs in expi- ration. He thinks it proved by Dr. Hales J s experiments b , that there is air in the cavity of the thorax, between the lungs and the pleura, and endeavours to take off the force of Dr. Houston's attesting that he faw the lungs and pleura contiguous. He grants, however, that fometimes there may be little or no air. He accounts for refpiration much in the fame way v/ith thofe who affume the contiguity of the lungs and pleura. He joins with thofe who think the impetus, which the internal furface of the lungs fuftains in common refpiration, to be very little. The ufes of refpiration are, to difcharge from the venal blood and chyle, fuch parts as are unfit to render them arterial blood, and to admit air into the blood. From this doctrine he accounts for the phenomena of the difeafes of the lungs. He fubjoins the picture and defcription of an ingenious instrument for il- lustrating the manner in which refpiration is performed. — [ a Lectures on Refpiration. ^ Veget. Statics exp. 112, 113. and Hamajlat. p. 83.]

Organs of Respiration, in fly worms. Thefe afford u not only great matter of admiration in their general ftruc ture, but by their almost endlefs variety in the different fpecies of thefe creatures, give ample room for the formi claries and genera from them. The firlt clafs of thefe creatures is of thofe with variable heads, whofe organs of refpiration are principally behind, the large fenfible stigmata, or breathing holes, being placed there ; and which have no fcaly legs, nor any regularly formed membranaceous ones; and which have, under their belly, certain fleihy protuberances, each feeming a portion of a ring, which is inflated at certain times. Thefe are the characters common to a vast clafs of thefe creatures, which are transformed into two winged flies ; but fecm never to be the marks of thefe which are produced from the eggs of the four winged clafs. Reaumur's Hill. Infect, Vol. 4. p. 164.

RESPONDEAS oufter., in law, is to anfwer over in an action to the merits of the caufe.

RESSELA, a term ufed by Paracelfus to fignify, as himfelf explains it, any thing that expels heat, in opposition to ajfa, which witii him signifies any thing that promotes it;

REST (Cycl.)— Monfieur de Maupertuis afferts, thit whm bodies are in equilibrio, they muff be fo fstuated, that if any fmall motion be impreffed on them, the quantity of ac- tion refulting will be the least poflible. This he calls the law of reft, and from this law he deduces the fundamental propofition of ftatics. See Mem. de l'Acad. de Berlin Tom. 2. p. 294.

Monfieur de Maupertuis deduces the laws of percuflson from the fame principle. See Quantity of Action.

RzsT-harrow, ononis, in botany, the name of a genus of plants, the characters of which are thefe. The flower is of the papilionaceous kind. The pistil arifes from the cup, and finally becomes a turgid feed veffel, in fome fpecies. longer, and in others ihotter, and usually containing kidney fhaped feeds. The characters of the leaves are, that they ufually grow three on each ftalk, though fometiines they ftand fingly in other parts of the fame plant. The fpecies of ononis enumerated by Mr. Tournefort are thefe. 1. The common prickly anonis with purple flowers. 2. The prickly ononis with white flowers. 3. The red flowered 'ononis without prickles. 4. The white flowered anonis without prickles. 5. The ononis with fmooth pro- cumbent stalks. 6. The least red flowered anonis without prickles. 7. The hairy and vifcous purple flowered fmall ononis. 8. The perennial red flowered ononis with broad, roundifh, and deeply ferrated leaves. 9, The early flower- ing purple mountain fhrubby ononis. 10. The Spanifh fhrubby anonis with fleihy tridentated leaves. 11. The low alpine anonis with a fweet flefhy root. 12. The fmooth fea anonis with flowers standing in the alas of the leaves. 13. The dwarf annual purple anonis. 14, The dwarf fmooth purple flowered alpine ononis without prickles. 15. The Sicilian ononis with the appearance of the alopecuros. 16. The round leaved Spanifh purple fpiked ationis without prickles. 17. The hoary procumbent fea ononis. 18. The purple flowered American fhiubby ononis, called by many crotola- via. 19. The great yellow vifcous anonis without prickles.

20. The fmooth anonis with yellow variegated flowers.

21. The broad leaved yellow annual vifcous ationis without prickles. 22. The annual broad leaved erect Portugal vif- cous ononis. 23. The narrow leaved fea ononis without prickles, with yellow variegated flowers. 24. The yellow flowered dwarf anonis with fmooth narrow leaves. 25. The little yellow French ononis without prickles. 26. The ononis with fmall yellow flowers. 27. The fhrubby Afiatic ononis with large yellow flowers. 28. The fhrubby Spanifh ononis with rounder leaves. 29. The rcfe leaved shrubby Spanifh anonis. 30. The broad and roundifh leaved American ono- nis. 31. The creeping bituminofe kidneybean-like anonis. Tourn. Inft. p. 408.

RESTY, (Cycl.) in the manege. A malicious unruly horfe, that fhrugs himfelf flioit, and will only go where he pleafes, is faid to be refly. A rejly horfc is much the fame with what the French call ramingue. See Ramingue.

RESUSCITATION (Cycl.)— Resuscitation bf plants, in chemistry, the art of reproducing a plant from its afhes. See Pai.ingenesia.

Many have pretended to this art, and have fliewn refufci- tated plants in vials c ; but all thefe feem only particular instances of artificial chemical vegetations, of which many others may be given. The external appearances of thefe refemble plants, and the ignorant may eafily take them for fuch ; but when clofely confidered, there is a great diffe- rence to be found. — [ c Boyle's Works Abr. Vol. 1. p. 69.] See artificial Vegetation.

RETCH, or Retches, a name given by our farmers to an iron, or a pair of irons, which in the common plow ferve to fasten the fheat to the beam. The retches are fastened to the fheat with nails, and to the beam with pins.

RETENEGI, in the materia medica, a name ufed by Avi- fenna, and others, to exprefs the common refm of the pine, or fir tree, and fometimes common black pitch. The lexi- cographers have given us fforax as the explanation of rete- negi, but this is not warranted by any paffage in the authors who ufe the wosd. It is certain, indeed, that the genera- lity of authors have confounded the feveral forts of refin and pitch making trees together, and among them the pine, fir, cedar, aisd turpentine trees, are called by the fame name, but the ftorax tree is never included among the number. Thefe were only confounded together, becaufe of the fimilitudeof the things they produced; but the ftorax was too different from all thefe, and too precious a gem not be distinguished. See Erz.

RETENTA, a word ufed by the medical writers to exprefs things retained in the body, or which are not to be retained in a state of good health.

RETENTION of the firjl Jlools, in infants. See Infant.

RETIARIUS, among the Romans, a kind of gladiator, who entered the lifts armed only with a trident in his left hand, and a net in his right. He was to ufe his utmost addrefs to throw the net over, and thereby entangle his antagonist; and if he miffed of his aim, he was to betake himfelf to flight, till he had the good luck to recover his net. Pitifc. Lex, Antiq. in voc.

a REIT