PARALLELOGRAM 



1489 



PARANA 



PARALLELOGRAM, pair a li I' 





PARALLELOGRAM OF FORCES, a me- 



chanical principle discovered by Newton, stated 



as follow-: "If two forces act on a point and 



if line- IM- drawn from that point representing 



:n magnitude and direction, and a 



PARALLELOGRAM OF FORCES 



\ force of 30 pounds acting at a towards 6 and 



ice of 40 pounds acting at if in the direction 



is equal to a single fm. . of .">n pounds in the 



tion of r. The same rule applies when the 



i\vo forces do not act at right angles, as in the 



oblique figure. In that diagram a and b are two 



forces acting with a force of 45 and 65 pounds. 



respectively. The resultant is a single force of 



01 poumis. 



parallelogram be constructed on these 



dee, their resultant will be represented in 

 magnitude and direction by that diagonal which 

 passes through the point." Although the resolu- 

 tion of two forces acting at right angles is the 

 1 common, in which case the parallelogram 

 is a rectangle, the principle holds equally for 

 oblique forces. See COMPOSITION OF F<>; 



PARALYSIS, paral'isis, or loss of the 

 power of voluntary movement, is in most cases 

 the resuk of some disorder of the nervous sys- 

 tem, as muscular movements are produced by 

 the stimulation of certain nerve cells. The seat 

 of disorder may be the brain or the spinal cord. 

 Many cases of paralysis are due to the brain 

 disease known as apoplexy, a full discussion of 

 which i> given in these volumes under the head- 

 ing APOPLEXY. Inasmuch a.s the motor il 



-p controlling movement) of each side of 

 the brain correspond with muscular groups upon 

 the opposite side of the body, trouble in the 

 riglr in in ! m causes paralysis on the 



left side of the body, and vice versa. 

 to the skull and abscess and tumor of the brain 

 causes of par.il.v-i-. In case of injury 

 to the spinal coid the patient ceases io hav 

 the power of movi \v tin- point of ni- 



nny There are certain diseases of tin- 

 notably infantile paralysis and spinal nunin- 

 L'Mi-. that cause lost of muscular m<\< < 

 In some instances, though these are the excep- 

 tion-. j'.ii.i\-is is a symptom of disease ot 

 d muscle. 



paralysis is determined 

 disease or inp 



aassage, electrical tivau. use 



of splints or other apparatus are among the 

 measures employed by modern physician- 

 help paralytics recover the use of affected 

 must 1 



Paralysis is derived from a Greek word mean- 

 ing In ilixahlt the x/</Y. The term , 

 applied to ,i condition of partial parah 



llrlnti-il ^uli.ii'ftN. Tin- . f.-rro.l to 



the following articles in these \i>li;- 

 Apoplexy Meningitis 



Infantile Paralysis \. ; \ >v-tom 



PARAMARIBO, pairamair'abo, the capital 

 of Dutch Guiana and the center of the trade of 

 the colony. It is situated on the right bank of 

 the Surinam River, about sixteen miles from 

 its mouth. The city is well built, and is \. 

 attractive by modern dwelling houses and 

 of orange tteefl along n- streets. Fon i 



landia. the residence of the governor, and ! 

 Amsterdam protect the large harbor. Sugar. 

 rum. molasse< and rubber are \t. n-i\ -. l\ 

 ported. Population in 1915. 35,530. SecDnvn 

 ( iri\\ \. 



PARANA, pahrahnah', one of the most im- 

 portant rivers of the world, and next to tho 

 Amazon, the largest in South America. It i< 

 formed in the southern part of Brazil by the 

 uniting of the Rio Grande and the Parana- 

 hyba, and flows in a general southerly direction 

 through Brazil, between that country and Para- 

 guay, and between Paraguay and Argentina. 

 then through Argentina until it finds an outlet 

 into the Atlantic Ocean, through the estuary of 

 the Plata (see PLATA, Rio DE LA). Near Cor- 

 rientes, on the boundary between Paraguay and 

 Argentina, it is joined by its largest tributary. 

 the Paraguay River (which see). At the head 

 of the Plata estuary it i- joined by the Uru- 

 guay. The total length of the river, from the 

 confluence of the Rio Grande and the Parana- 



hyl>a to the or, ,11. M L>.:,W mile-; excluding the 



Plata, it is 2.270 miles. It has a drainage basin 

 nearly equal to that of the Mississippi, and it 

 is about the length of that stream, excluding 

 the Missouri. 



Below its confluence with the Paraguay, the 

 Parana traverses the level pampas of Argcn- 

 ima. and for a distance of a thousand miles is 

 n a\ liable for large riv 



steamers sail through the Plata estuary and up 

 the stream as far as Rosai 400 



nulrs from the Atlantic. In its lower course 

 the Parana divide- into nuinerou- rh.u, 



,e of which ate two mile- m widtl 

 its confluence with tho Paraguay are sr\ 



