New ploughs for Scotland: the chilled plough

In the second half of the 1870s when the chilled plough was introduced from America into Scotland there was extensive debate about it and its merits. This debate continued into at least the early 1890s. Even then there continued to be extensive debate and discussion. An important lecture on the chilled plough was delivered by John Speir, Newton Farm, Cambuslang, to the Airth Agricultural Science Class. Speir was a well-known farmer at that time and wrote a number of important articles on implements and machines which were influential in helping to get new ones established in Scotland.

An article of his lecture to the Airth Agricultural Science Class was published in the North British Agriculturist on 20 April 1892. It is worth quoting at length for his insights into ploughs and ploughing and the chilled plough.

“During the last fifty years most agricultural implements have undergone an immense improvement. In most cases the improved machine or implement does its work better, cheaper, and speedier than could be done by the old one, as, for instance, threshing and reaping; but while speed was being attained, a more costly machine has to be provided, entailing more expense on the farmer for interest and repairs. In the matter of ploughs, however, no such advance has been made; in fact, since the introduction of the iron plough, very little improvement has been made at all. In every district new designs have every now and again been introduced, which were supposed to be improvements in some particular part on those which had preceded them. Many of these improvements were more fanciful than real, and were often the designs of other localities, where nothing new or very important was claimed for them.

Allowing slight variation of design for particular districts, soils, and classes of work to be done, it may be said that very few improvements have been effected on the plough of any great importance for a very long time, and that the principles on which the ploughs of the Romans were made very much the same as the ordinary Scotch plough generally is, only the material of which it is now made has changed from wood to iron, owing to the greater plentifulness and lower price of the latter.

The Essex plough of to-day is probably the nearest approach of any working plough at the present time to what the old plough of Britain was. At present that plough has a long, sweeping, and gently twisted mould-board of iron, but in many other respects it is supposed to be very much the same as what it was many hundred years ago. The body of the plough is of iron, while the handles or stilts are of wood, one of which alone is permanently fixed to the body. It is on this one (the left one) that probably two-thirds or three-fourths of the whole power of the ploughman is exercised in guiding it, in very much the same way as the inhabitant of Palestine guides this one-handled plough at the present day. The right handle is usually a long pole, often an oak or ask sapling, one end of which passes through a ring at the tail of the reist or mould-board and into a socket, into neither of which is it very firmly fixed, nor is it in any way braced to the body of the plough or the other handle. Owing to the want of bracing, the consequence us that, when any force is exerted on it, it yields very materially, and in the hands of any one who has held a well-braced plough, this one feels as if one had no power over it. Notwithstanding this defect the Essex plough, in the hands of a good ploughman accustomed to its use, makes good work on probably some of the stiffest lands of Great Britain, and by the natives of the county is preferred to most other patterns of more recently introduced ploughs. I wish this remark to be particularly taken note of, as I have purposely referred to the Essex plough as being probably the oldest pattern in daily use in Britain, to show that, even under adverse circumstances, a good ploughman may make good work with a very indifferent implement if quite accustomed to it, and in many instances he will prefer it to be a newer and probably better design, so that where other facts go to prove something else, the ploughman’s likes or dislikes should be properly discounted.


To Mr James Fleming, Carmuirs, Larbert, is undoubtedly due the honour of introducing the first American chilled plough, and which has been the precurser of the enormous number which have followed since. A certain Mr Turnbull, a farmer in America, happened to call on Mr Fleming, and in talking over farming matters, as carried on in America, he mentioned this plough, and Mr Fleming instructed him to send him one as soon as he arrived home. This was the summer of 1879, and in the autumn of that year a plough arrived. Mr Scott, implement agent, Bonnybridge, who is a nephew of the gentleman who brought the plough under Mr Fleming’s notice, got the loan of the plough and tried it under various conditions. He was so satisfied with its work that he ordered a limited number from the makers, Messrs Oliver, South Bend, Ind, USA. Mr Scott continued to import them in limited numbers till 1885, when Messrs John Wallace & Sons, Graham Square, Glasgow, were appointed agents for Great Britain and Ireland, since which date the sale of these ploughs has increased enormously. Other ploughs by other makers, of much the same class, have been introduced in limited numbers, but none of them have got any footing in Britain at all compared with the Oliver. James Oliver, senior, by the way, is a Scotch-man by birth, being a native of one of the Border counties, but has been in America over fifty years. The present business, which was begun by the senior partner of the firm, is now carried on by Mr Oliver, senior, his son, and son-in-law. The works are very extensive, covering 40 acres of land, and employing 800 men.


The chilling of iron, although known and patented in this country since 1852 at least (the late Mr Howard, of Bedford, having in April of that year, taken out a patent for that purpose), made little or no progress until the introduction of what is now known as the American chilled plough. Chilling was used and is used extensively by several English firms in connection with the manufacture of socks and shares for ordinary swing ploughs; but, as far as my experience goes, little, if anything, was done in the way of chilling the reist, breast, or mould-board as it is variously called, and to which a considerable part of the superiority of the American plough is due.

Method of chilling

Although the chilled plough differs from the swing plough in many particulars, in all probability the most important is the chilling of the face of the reist or mould-board and sock. This is effected while these are being cast, by pressing against the hot metal a thick piece of iron of the same shape as the face of the part to be chilled. This has the effect of rapidly cooling the outside surface, leaving the other parts of the metal to do so more slowly, whereby they retain much more toughness and strength than the hardened part. The piece of metal used for moulding and chilling the face of the reist is slightly cut into a checked pattern on the side next to that which is to be hardened. These minute gutters or furrows allow the air to escape which has gathered between the molten metal and the chilling plate, it having been found that when such a provision was not made a thin film of air was confined between the two metals, and air being a bad conductor of heat, the chilling was not so perfect as when the checking mode was adopted. A peculiar bend of metal is also used regarding which the Messrs Oliver are very particular.

General appearance

In the American pattern of the chilled plough, as generally seen in this country, the beam and handles are usually of wood, while the total length of the plough is about one-third less than that of the swing one, which is always made of iron. To most people these ploughs at first sight appear uncouth, unsightly, and old-fashioned, more particularly owing to the large quantity of wood used in their construction. When in the U.S.A, recently, I visited the Oliver Plough Works, and was very kindly shown over the whole place, and was much surprised to find that very many of the patterns of ploughs made for sale in such a dry climate as the U.S.A. had iron beams, while those sent to the wet climate of Britain were mostly made with wooden beams. The makers say that experience has taught them that wooden beamed ploughs do not wear the land sides and shares so quickly as iron beamed ones. I have, however, no facts to bear this out, and can only understand it in the light of the heavier plough causing more friction, and consequently more wear.

Curve of the reist

In the American chilled plough the curve of the reist or mould-board in concave, while in the swing plough it is convex; the former is also very short, while the latter is usually considerably longer. The concave pattern, combined with the hardened surface and excessive polish which these reists take on, almost entirely prevents the most plastic soils from sticking on them.

Easiness held

Many people are apt to suppose that a long-handled plough is easier to hold that one having short handles, but the experience of the use of the American chilled plough is quite antagonistic to that theory. The chilled plough, having a wheel under the beam, to a great extent regulates its own depth, while the breadth is extra-ordinarily easily controlled. A good ploughman quite unconsciously, and with very little effort, very accurately regulates his depth with the swing plough, but in the hands of a learner, or indifferent workman, the regulation of the depth is not an easy matter. The chilled plough is, however, so well balanced in all its parts, that the power or skill requisite to guide it is reduced toa. Very low limit. So little is the exertion necessary to guide this plough in land free of stones, and of moderately open texture, that it is not a difficult feat to do so with one hand, and yet make very respectable work. A learner can do moderate work with these ploughs much sooner than he can with the swing ones. An objection of a minor kind against the chilled plough is that the furrow ends and head ridges are generally left in an untidy state by them. This undoubtedly is the case, but at the same time it is of necessity need not be so, as far as the ends are concerned, if only a little care and taste are exercised over the work. The rough state in which the headlands are left, particularly on soft ground, during wet weather, is not so easily got over, as the ploughs do not slide well on the heel, and repeated sliding in the one track on the reist soon furrows the headland. If, however, a little care is exercised here also, no great objection need be made to them even on this score.

The furrow

The furrow taken as cut or as left by these two ploughs is as different from each other as it is possible for the work of two implements bearing the same name to be. The swing plough when working lea generally cuts a furrow from 8 inches to 10 inches broad, and from 6 inches to 7 inches deep, although ion some prize ploughs made by Gray and others at Uddingston and in the district around Glasgow the usual furrow to cut is 6 inches to 7 inches broad, and 8 inches to 9 inches deep at the point of the sock but only 5 ½ inches to 6 inches at the tail of the feather or wing. In the chilled plough the furrow is seldom less than 11 inches or 12 inches broad, the average running from 12 inches to 16 inches, according to class of plough. Most of the chilled ploughs work moderately well at any depth up to 9 inches or 10 inches, so that it is at once evident that the two ploughs have very little in common.


Any plough to work well, or be easily drawn, must be worked with a furrow of a breadth and depth suited to its capacity. When the two ploughs are tested in this way it is found that the chilled one is much the easier drawn of the two. The first recorded experiments made in this country to test the draught of the chilled plough versus the swing plough seem to have been carried out at Glasterberry, in Aberdeenshire, by Professor Jamieson, and Mr Gray, engineer, during the winter of 1884-85. They made tests by drawing the ploughs by a windlass, in order to get a steady pull, and by horses in the usual way, both ploughs being regulated to go 7 inches deep.

In the lea trial the swing plough cut a furrow 10 ½ inches broad, while the Oliver chilled plough took 13 inches broad. Drawn by the windlass the draught of the swing plough was 3 ¾ cwts, while the Oliver plough was 2 cwt.

These trials show a gain in draught of from two to two and a half times in favour of the chilled plough, which is considerably more than most people were inclined to acknowledge or even believe.

Probable causes of lightness of draught

The question may be asked, wherein does the saving of draught lie, is it in the pattern of the reist, the share, or general get up of the plough, or what? As in ploughing an acre of land, both must turn over an equal weight of earth, and one would fancy the plough turning the furrows right over would be heavier in draught than the other which turned them only half over or on their edge, as the swing plough does. My experience of both leads me to believe that the gain in draught of the chilled plough arises from many causes, and not from one alone. Probably 60 per cent of the whole gain arises from the material and finish of the mould-board or reist, the remainder being derived from several different causes. The concave pattern apparently has the power of compelling the furrow to press more uniformly on its surface than happens with the convex pattern; it consequently keeps close to it all the way from the share to the tail of the reist. The newly cut furrow appears to continually press, as it were, under the part which has gone before it, thus preventing any soil from sticking on any part of the surface. The extremely hard surface and splendid polish with which the mould-boards of these ploughs are sent out has undoubtedly a very great effect in preventing the soil from sticking, and in consequence lessening the draught, and to it I am inclined to ascribe a very great part of the gain. This was very apparent to me in some trials I made during the winter of 1887 and 1888 with two ploughs, each designed to cut the same size of furrow, both with concave reists or mould-boards, and of about the same total weight. Looking at the ploughs one would have been inclined to say there would be very little difference in their draught, but repeated tests showed that the one was very much easier drawn than the other, the difference being about 20 per cent. Nothing in the construction of the ploughs appeared to warrant such a difference, the design of the mould-board being the only part in which they varied materially. Trials were, therefore, made on various classes of land, at different depths, and in every case with the same result. During the continuance of these trials it was noticed that although both reists kept beautifully clear, the one was very much brighter than the other, and had a polish like a mirror, while the other, although clear, was dull. On looking further into the matter, the one reist appeared to be very much better chilled than the other, and to this cause the difference in draught in great part appeared to depend.

When a chilled reist is broken, it will be found on closely examining the broken surface that the iron appears to be of finer grain and more dense near the hardened surface, than it is inside the body of metal.”

What do you think of Mr Speirs’ lecture?