220 



THE POPULAR EDUCATOR. 



Fig. 37. 



only rise till its pressure -was such as to balance that of the 

 air. This height is found to vary between thirty and thirty- 

 four feet. 



We see then that though this pump is generally used, it will 

 not answer when the water has to be raised more than thirty 

 feet, nor will it raise it above its own level. In cases, therefore, 

 where these are required, a different kind, known as the Force 

 Pump, is employed (Fig. 37). This machine is usually placed some 

 distance above the level of the water, which is first raised in it on 

 the principle of the ordinary pump, and 

 then forced to the required elevation. 

 The annexed illustration will explain 

 its construction. The suction-pipe and 

 barrel are constructed in exactly the 

 same way as in the common pump; the 

 plunger, however, instead of having a 

 valve in it, is made solid ; and, instead 

 of the spout for the water to issue from, 

 a pipe leads from the lower part of the 

 "barrel to a reservoir or air-chamber, c. 

 A valve, B, closes the opening of this, 

 and another pipe, D, passes into the 

 reservoir, its mouth being rather below 

 the middle ; up this pipe the water is 

 forced. We will suppose the barrel to 

 be full of water, and the piston just 

 beginning to descend. The valve A 

 closes at once, and the water, 'having 

 no other escape, passes through the 

 valve B into the reservoir c. The air 

 which fills the part of this above the mouth of the pipe acts as a 

 spring, and checks the flow, but by its reaction forces the water 

 up the pipe D. When the piston again rises, B closes, and a 

 fresh supply of water enters through A, and the same process is 

 repeated at each stroke. 



This pump is very similar in construction to the lifting pump 

 before described, only it is placed above the water, thereby 

 saving the weight of the rods, and it acts partly by suction. 

 When made in this way, the greatest strain if the water has 

 to be raised to any great height is when the handle is being 

 raised. This is rather a disadvantage, and to remedy it the 

 top of the barrel is sometimes closed, the pump-rod being made 

 to work through a collar, which is packed to prevent the escape 

 of the water. A valve is then placed in the piston, and the 

 pipe leading to the air-chamber proceeds 

 from the upper instead of from the 

 lower part of the barrel. The water in 

 this way rises above the piston, and 

 when the latter is raised, is forced into 

 the chamber, and thus up the pipe D. 



In either of these modes of construc- 

 tion the water is only raised while the 

 piston is moving in one direction. A 

 reference to the figure will show that 

 when the piston is rising it draws up 

 the water into the barrel, and when it 

 descends it forces it into the reservoir. 

 A plan has, however, been devised by 

 which both these processes may be 

 carried on simultaneously, and thus a 

 constant stream of. water be produced. 

 A branch of the supply-pipe, A (Fig. 38), 

 enters the lower part of the cylinder at 

 a, and another branch enters the upper 

 part at It ; in the same way branches of 

 the exit-pipe, B, communicate with the 

 upper and lower parts of the cylinder at 

 c and d. These openings are closed by valves which all open 

 to the right. The piston is solid, and in the figure is supposed 

 to be descending ; the valve 6 at the upper supply-pipe is 

 therefore open, and the water is sucked up through it into the 

 cylinder, at the same time the water under the piston is being 

 driven up the lower exit-pipe. When the motion of the piston 

 is reversed, the other two valves open, and the water enters by 

 the lower supply-pipe, and escapes by the upper exit. A 

 constant flow is thus produced ; a further advantage of this is 

 that the pressure is the same on the piston-rod whichever way 

 tt is moving. 



Fig. 38. 



THE THEORY AND PRACTICE OF 

 EDUCATION. IV. 



EMINENT TEACHERS, PRACTICAL AND THEORETICAL. 



NEVER, probably, since the world began, has so much and such 

 universal attention been paid to the theory and practice of 

 education as at the present time. Various causes have by 

 slow degrees led up to this result. The dominating spirit of 

 the Christian faith, as developed and exemplified by its Divine 

 Founder, is that of love love to God, and love to his crea- 

 tures. " Inasmuch as ye have done it unto one of the least of 

 these my brethren, ye have done it unto me." This love has 

 manifested itself among Christian nations in every age, since 

 the Saviour enunciated the great command, " Thou shalt love thy 

 neighbour as thyself," by unceasing efforts and sacrifices for 

 the relief of poverty and distress. But Experience is a great 

 teacher ; and we have slowly learnt from hia instructions that 

 Ignorance is the fruitful parent of many evils, and are now 

 seeking to prevent by the spread of knowledge the miseries 

 which formerly we have only sought to relieve. Again, this 

 gradual growth of healthy opinion in favour of education has 

 been accompanied by an improved comprehension of its true 

 nature, a fuller sense of the elements of which it consists, and 

 of the methods by which it may be imparted with the greatest 

 probability of success. One after another, as the ages have 

 rolled away, men of wide sympathies, earnest aspirations, loving 

 hearts, and philosophic minds have arisen, who have given 

 mighty impulses to the cause, chased away antiquated notions, 

 and purified the aims and directed the efforts of those who have 

 sought to render education, in the best sense, the birthright and 

 abiding possession of all mankind. This article will be devoted 

 to a few of the most prominent amongst these worthies. 



Socrates was born B.C. 469, near the town of Athens, the 

 capital of Greece, and was one of the most celebrated philo- 

 sophers and teachers of ancient times. This is not the place to 

 speak of his exploits in war, his labours and triumphs in philo- 

 sophy, his domestic trials, or his untimely death. We mention 

 him here because he was the first, as far as history reveals to 

 us, who systematically employed the interrogative method of 

 teaching which is now in such general use amongst practical 

 educators. It is sometimes called "the Socratic Method." He 

 neither opened a school nor gave public lectures, like other 

 philosophers of that period, but went about into all the public 

 places of the city, seeking to arouse a desire for knowledge and 

 a love of right in the hearts and minds of all who would listen 

 to him, whether young or old. He first sought to drive out of 

 the minds of his pupils all false conceit of knowledge, and 

 to make them deeply sensible of their ignorance ; and then 

 would proceed to explain to them in the clearest manner the 

 things which they ought to know. 



John Milton, the sublime poet, the wise and far-seeing states- 

 man, lived from 1608 to 1674. Besides other prose works, he 

 wrote a tractate on education about the year 1644, addressing 

 it to " Master Samuel Hartlib." In this production, Milton 

 severely censures the practice which was then prevalent, of 

 spending " seven or eight years merely in scraping together so 

 much miserable Latin and Greek as might be learned otherwise 

 easily and delightfully in one year." He then rapidly sketches 

 out a plan of education in general terms, taking in a vast range 

 of study, and a complete course of physical exercise, intended 

 to make good men and good governors, and " such as shall 

 deserve the regard and honour of all men where they pass, and 

 the society and friendship of those in all places who are best 

 and most eminent." But he entirely overlooks the training and 

 instruction of the poorer classes a subject which now engrosses 

 almost universal attention and solicitude. 



John Locke was born at Wrington, in Gloucestershire, in the 

 year 1632, and died in 1704. He was educated at Westminster 

 School, from whence he passed to Oxford. In 1664 he went 

 to Berlin as secretary to Sir W. Swan, arid on his return to 

 England in 1665 became acquainted with Lord Ashley, after- 

 wards Earl of Shaftesbury, and formed with him a friend- 

 ship which continued until the death of that nobleman. In 

 1687 Mr. Locke completed his great work " Concerning the 

 Human Understanding," and about the year 1693 he published 

 his " Thoughts Concerning Education," a work which was 

 destined to produce important changes in the system of educa- 

 tion which was then in use. He commences his remarks with 



