l;oT ATloX OK CROPS. 





IM 



vr utlle vcgcaDW miTT~ uruiuii uivui urn >"' . 



In many countries) there are other vegetable prinlucts, which ore 

 raquind for the food of the inhabitants, or supply the raw materials of 

 manufacture* : thaw mutt bo introduced into the rotations, according 

 to their eflert on the soil and the cultivation they require. Indian 

 corn, or maiae, aud Kivneh beans, for their seed, are cultivated in more , 

 uutheni climates as field crops. 1'otatoe* are now an esaential product 

 uno* aid one which, after mai/e, produces the greatest 



quantity of f-xi for man from a given portion of laud. But potatoes 

 require much manure, and cannot profitably be cultivated to a very 

 great extent a* a farm produce, nor repeated on the same land, for any 

 length of time, oftener than once in eight or ten years ; they should j 

 boe\rr always enter into the rotation in that portion of the land 

 vhich is tu be much worked, cleaned, and manured after a crop of 



\Ve have ourselves for many years adopted a rotation without being 

 tied down to any positive rule, which has been suggested by circum- 

 itrr** and in some measure regulated by our conviction of the truth 

 of the theory w e have attempted to elucidate. In a clayey loam on an 

 impervious subsoil, but mostly completely drained, we have had 

 turnips and swedes on high ridges, tares, mangel-wurzel, potatoes, and 

 a portion of rye to cut up green ; succeeded by barley and oats sown 

 with clover, rye-grass, and other biennial gnus seeds. These were 

 mown for hay the first year, and sometimes the second also, but 

 generally depastured one year at least ; then followed beans, and after 

 these wheat. The green crops were put in after repeated ai, 

 tillage, and with an ample allowance of manure. The whole of the 

 layer was top-dressed with peat or coal ashea in the first year, and 

 what manure could be got or spared was put on the second year before 

 winter, when it was ploughed up. All the corn crops were put in 

 upon one shallow ploughing. We have had no reason ro repent of 

 pursuing this course : but we allow that one year only in clover would 

 probably be more profitable. The land is not sufficiently fertile by 

 nature to bear wheat after the first year of clover, instead of feeding or 

 making it into hay. This would bring it to some of the rotations 

 adopted in rich alluvial soils. It is a rule which should never be 

 transgressed, Out after every ciop reaped there should be a remnant 

 of manure suliicient U> ensure a good crop the next year ; and that this 

 i-houM always be in the land, and considered as stock in trade or 

 capital invested at good interest. By means of judicious rotations and 

 tillage a much greater quantity of produce may be raised at a certain 

 expense of labour and capital, than by any desultory and experimental 

 mode of cropping. The farmer should find it his own interest to 

 cultivate his land according to the nic.gt approved principles, aud the, 

 landlord ehould impose only such restriction as will prevent the tenant 

 from injuring hiuiself by diminishing the produce of his form. 



It is in the relation of crops to manure to the need of it for them, 

 and the supply of it through them, that the practical man fees the 

 advantage of rotations. There is a need of rotations arising out of our 

 relations U> our labourers who want constant employment to our live 

 stock, which need constant food to the soil, which will not continue to 

 produce the same plant per|*tually to the plants we cultivate, which 

 grow moie luxuriantly in rotation than in constant succession. And 

 the explanation of this last fact has been founded on the ideas that (1) 

 crops poison the land for themselves ; (2) that they exhaust the laud 

 for themselves; (3) that they improve the ground for their snr, 

 Turnips for instance consumed on the land bring on it more nitro- 

 genous matter than was given them in their manure ; and HO t ! 

 ia enriched by Uti< practice and rendered fit for groin, which on the 

 uther lisnd u*i more nitrogenous matter than it can in general 

 naturally obtain. 



The following are our common rotations 



l,is the Norfolk rotation -2, the North of England modification of it 

 --3, Mr. Thomas's, of Lidliugton, modification of it 4, a common 

 modification of it in Norfolk 5, the East Lothian 6-field rotation 6, 

 a common modification of it 7, the Whitfield 8-u'eld course 8, 

 Hewitt Davis's light land rotation 9, the rotation of the Cotteewold 

 district, Gloucestershire 10, common in the fens of Lincolnshire 11, 

 in clay-lands, East Lothian 12, carse-londg of Scotland 13, clay-land* 

 of Essex. These rotations vary greatly in their manure producing 

 power. By some one cwt. of meat may be made per aero by > 

 not a quarter of a cwt. By some therefore there is food per acre for 

 on ox, making 20 tons of dung for every 4 acres, aud on others hardly 

 one for every 10 acres. 



ROTATORY OK CIRCULAR POLARIZATION. [POI.AIIIXV 

 noifj 



RdTE, a musical instrument of former times, mentioned by the 

 early Freuch writers of romance, and by Chaucer, as well as others 

 among our early poets : it seems to have been similar to what the 

 French call a tittle, and the English a hurdy-gunly. 



lit iTTKN.Vl'i )N I".. [E.MKUV ; 7W/. Puirtl' r. j 



ROTUNDA, a term applied to buildings which are circular in their 

 plan both externally and internally, or else to halls and other : 

 incuts of that shape, included within and forming merely a portion of 

 the edifice containing them. The technical application of the term i.i 

 however restricted to circular buildings whose height does not much 

 exceed their diameter, for we should not describe a lofty cylindrical 

 edifice, such as a round tower, by the term rotunda ; while on the 

 contrary it is frequently employed to designate polygonal buildings 

 which approach in their general form to the circle. 



In ecclesiastical architecture circular and polygonal structures were 

 by no means uncommon among the early Christians, especially for 

 baptisteries and sepulchral chapels. The tomb of Theodoric, or what 

 is now called Santa Maria Rotunda, at Ravenna, is a singular example, 

 having a flattish or segmeutal dome (about 34 feet in diameter) cut 

 out of a single block of stone. Of San Stefano Rotundo and Santa 

 Costanza mention has been made under ROMAN Am inn i i n;r, and to 

 them may be here added the Rotunda or Church of Santa Maria 

 Maggiore at Nocera, a work of about the same period. While it 

 greatly resembles Santa Costanza in plan, having coupled columns 

 placed on the radiating lines from the centre, and with arches springing 

 from them, it differs altogether in section from both those examples, 

 there being no cylindrical wall or tambour above the colonnade. 1 nit, 

 the dome springs immediately from the columns, and the arches 

 groining into it. Consequently the proportions are much lower, the 

 diameter of the space enclosed by the columns being 3SI feet, and the 

 height to the top of the dome 42, proportions differing very little 

 from those of the Pantheon. The extreme internal diameter is 78 feel. 

 The earlier edifices of this class are, for the most part, of moderate 

 dimensions, but others were afterwards erected on a larger seal 

 among them is the celebrated baptistery at Pisa [BiPTBTKRI |, which 

 is externally about 120 feet in diameter, and 100 in height, exclusive 

 of the dome. Circular churches, or baptisteries, arc also of fit 

 occurrence in Germany aud Franco ; aud in England are t i 

 round churches of semi-Norman (12th century) character which are 

 supposed to have been designed in imitation of the Church of the 

 Holy Sepulchre at Jerusalem : such are the round church 

 Cambridge and Northampton, and the Temple Church, I, ndou. 



The rotunda became afterwards in a manner incorporated will i or 

 added to the cruciform plan, being raised aloft and placed ovei 

 part of it where the transepts intersect the body of the edifice. 

 Nearly all modern cupolas may be described as rotundas elevated 

 above the rest of the building and viewed by looking up into them 

 from below. Thus suppcuring there was a floor at the level of the 

 ring gallery at St. Pauls, the dome and space beneath it would 

 form a perfect and well proportioned rotunda, whose heigh' 

 diameter would very nearly be the same. 



In itself alone the rotunda form does not accommodate itself to the 

 purposes of a church : it does not afford space for the proc 

 occasional ceremonies required by the Roman Catholic worship; nor 

 is it better fitted for the Protestant service from its requiring an 

 amphitheatrical arrangement of seat* in concentric curves. Rotund is 

 are accordingly rare even in Roman Catholic churches, yet although 

 such structures are necessarily limited by their form to 

 si/.e, they derive from it, also a grandeur which would not be produced 

 by the same scale according to any other plan. Neither grandeur nor 

 beauty however results aa matter of course from the plan 

 because whatever charm that possesses may be nullified by other 

 ciivmiiHtonces. There is, for instance, nothing of the one and not 

 very much more of the other in the rotunda interior of St. Peter-le- 

 Poor's, London, one of the few instances we are acquainted with of 



