of fianged discs, each fitting in a housing carried below thehopper@ (Fig. 4). Each fange is fiuted on the inside andOne flange is broader than the other. A flap inside the hopper directs the grain into either the broader (coarse) orthe narrower (fine) side of the disc, The disc is driven bya square shaft which passes through the housing and as itrevolves some seed is carried round by the fiutes and fallsinto the coulter tubes. The sowing rate may be altered either by using the coarse or fine side or by altering thespeed of the discs. This is done by means of a face gear,a large flat gear with concentric circles of teeth. Thedriving gear is moved across these circles of teeth, eachcircle being a different gear.After the seed has been metered, it falls down thecoulter tubes into a groove or furrow, formed by the coulters. These are usually discs, as they are suitable for mostsoil types and conditions.They are able to withstand block-age by surface trash or clods. The seeds are covered bysoil falling back into place, after it has been disturbed.Each disc is attached by a lever to the crossbar at thefront of the drill and pressed into the ground by a spring.It is able to move independently of others, and rides overstones or other objects without damage. The depth of sow-ing is controlled by twisting the crossbar which alters thecompression of the springs. The soil type and conditioninfuences how far a particular spring pressure will causethe disc to penetrate@. The discs are normally spaced 175mm apart but on some external force feed types the spac-ing isreduced to'11o mm.The drive to the feeding mechanism is taken from the18
lowthewheels. In some drills each wheel drives through a ratchedeandto allow a differential effect when cornering to ensurethahehop-drive is taken from the faster of tho two wheels. The cliclrse)oring of the ratchets when cornering is probably a familiaiven bysound@.On other types, usually narrower models,eacnd asitwheel drives half the mechanisms. The whole series of coundfallsters may be either raised or lowered bya seif-lift mechaered ei-nism driven from the wheels or on the latest models by hingthedraulic linkage or hydraulic rams on each wheel, operateegear,by the tractor's hydraulic system. As the coulters rise ou5.Theof the ground the sowing mechanism is automatically disa,eachengaged.It is most important to get correct matchingof thwnthebouts to avoid overlapping or double drilling and to prehecoul-vent gaps between the bouts. On wide grain drills this iormostobtained by markers and these should be set so that whed block-driving the front wheel of the tractor on the mark madered byby the marker on the previous bout the outside row sturbed.grain is the distance between the coulters from the adjoinattheing bout?.spring.des overWords and Expressionsof sow-terstheari[dril]n.条播机排种装置coulter【koulta]n.开沟器grain～谷物条播机onditionversatile['vo:sotail]a.万用的，通~tube输种管llcause用的，多方面适用的plant[plarnt]vt.裁种，播种n.faced175essence[esns】n.本质，实质物；植物；工厂in~本质上，大体上~ing and covering mechanisrhe spac-hopper[hapa]】n、箱，种子箱播种覆土机构feed[fi:d](fed,fed)v.喂；送，供sow[sou]vt.播种fromthe给~ingwidth播幅metering and ~ing device 定量multiply['maltiplai]vt.乘
external[eks'ta:nal]a.外部的动，翻动~force feed外槽轮排种装置crossbar["krosba:]】n.横梁，横杆roller['roula】n.浪轮；排种槽轮ride[raid]vi.骑（马)，浮动Fute[fluit]vi.刻凹槽n.凹槽twist[twist]vf.拧，扭housing["hauzin]n，壳体，罩cmpression[kam'prefan]n.压adjustable[o'dsastabl]a：可调的缩：压力flap[flep]n.挡板：挡帘infuence[infiuons]vt.影响circumference[sa'kamfarons]n.ratchet['ratfit] n.辣轮周，周围；周线（边）differential[difa'renfal]a.差动的;remainder[ri'meinda]n.剩余，残有差别的余corner["koina]vi.转弯n.角落sprocket n.链轮ensure[in'fua]vt，保证，确保internal[in'to:nl]a.内部的click[klik]yi."-卡嗒"响声~force feed mechanism内撸self-lift[self-lift]】n.自动起落（提轮排种机构升）器flange[Hends]】n.凸缘，法兰盘linkage["linkida】n，悬挂装置~ddisc带凸缘的圆盘hydraulic～液压悬挂装置direct[di'rekt】vt.导向；指导disengage[disin'geids]】vt.分离，coarse[ko:s] a.粗的脱开narrow[nerau]a.窄的automatically [:ta'metikoli] ad.revolve[ri'volv]vi.旋转自动地face[feis]n.脸，面match[maet]y.配合，匹配~gear平面齿轮bout[baut】n，（田间作业的）行程concentric[kon'sentrik]a.同心的(回，越）集中的overlap[iauvo"laep]yi.重选，重播circle['sok]n.圆环gap[gep】n.漏播，间隙，空隙groove[gru:v]n.摘，沟marker['ma:ko】n.划行器withstand [wia'staend](withstoodprevious[prirvjos】a.以前的，先前[wis'studDvt.顶得住，经受住的blockage【"blokids]】n.障碍，堵塞adjoining[e'doinin]a.相邻的，旺clod[klod]n.土块，泥块邻的disturb[dis'toib]vt.扰动（乱，搅Notes①This consists of a roller, part of which is fluted,rotating in a hous-ingbelowthehopper，句中（partof）which引导非限制性定语从句，它和后面的分词短语rotating，thehopper并列在一起，修饰roller。全句可译为：这种排种装置有一个滚轮，轮上有一部分开有槽沟，滚轮在种20
子箱下面的壳体中旋转。②between thefiutes of theroller:经措轮的沟槽。梁，横杆?to permitdifferentsizesof seed to be sown:为了能播大小不同力子。该不定式短语作目的状语，修饰maybefited，其中被动态不定式besown作宾语differentsizes of seed的补足语。Jn压④each fitting in a housing carried below thehopper:每个圆盘分另彩响装在种子箱下面的一个亮体中。当分词前有名词或代词作逻辑主语而利词一起组成主谓结构时，这种分询短语称为独立分调结构；本独立分词差动的；作状语，表示对句子的前一部分作附加说明。?a large flat gear with concentric circles of teeth:此为 face gearn.角落同位语，为：带有着干个同心齿环的大平面齿轮。确保?how far a particular spring pressure will cause the disc to pe期trate:（特定的）弹簧压力迫使圆盘人土的深度（入土多深）。疑间副词h动起落（提（far）引导宾语从句。?The clicking of the ratchets when cornering is probably a fami装置sound.句中when cornering相当于when they（代表drills）are装置nering，为时间状语从句，修饰动名调clicking。y.分离，the outside row of grain is the distancebetween the coulters fr8ikolil ad.the adjoiningbout：本句的原意为：外行离邻接行程的距离为开沟器的距。可译为：两个行程的邻接行距等于开沟器的间距。配业的）行程送，重播空院器前的，先前相邻的，毗in a hous-定语从句，饰roller。，滚轮在种
5.PADDYTRANSPLANTERSHand transplanting is a slow process,consumingmorelabour than any other operation in paddy planting@. Theagronomic advantage to be derived from transplanting,however, at least under Asian conditions, is so well estab-lished that mechanization of this operation merits closeattention by agricultural engineers.In only a few countries have serious attempts beenmade to devise transplanting machines@. One machine thatachieved some success was the ILCMA in Italy,developedfor power take-off by a tractor of about 1.5 tons in weightequipped with steel wheels having a width of 65 mm andprovided with spikes.Seedlings from the nursery are arranged in magazineswhich are fed into the transplanter by two operators.Eachoperator feeds three rows and also makes minor adjust-ments to the machine by means of conveniently located le-yers. When the magazine is fed into the machine, the seed.lings are gripped between the internal surfaces of revolvingpincers which pull the seedlings from the magazine, takethem down into the soil and leave them planted in the fur-row. The number of plants in a given surface is govern-ed by the speed of the tractor and power take off andthe number of seedlings contained in the magazine. It ispossible to regulate the density of plants by various adjust-ments. Spacing of rows is fixed by the dimensions of the22