29 MAY 1920, Page 7

PISS AT THE BRITISH MUSEUM..

THE student of the literature of Pise de term will remember that through all writings on the subject during the last hundred years there flits the phantom of Mr. Holland's Communication to- the Board. of Agriculture, Strangely enough, however, though no writer on rise ever fails to allude to it, no writer on Pise ever professes to quote from it, and we doubt very much by the context whether any of them had seen it. Mr. Holland, we may note, was an architect who practised at the close of the eighteenth century and who took up Pise, and, like a sensible man, recommended it to the Board of Agriculture as worthy of their attention. The Board appear like so many public offices before and since to have printed his Communication, crossed their legs and sat still. At last after some diffi- culties we have been able to run down and dig out Mr. Holland's Communication. It went to earth in the British Museum and not as one might have expected in the Record Office, to which, after a certain term of years, superfluous papers are sent by public departments. In the British Museum, in a book entitled Communications to the Board of Agriculture on Subjects Relative to the Husbandry and Internal. Improvement of the Country," published in London, 1797, there is in Vol I. an appendix which contains an essay on Pise consisting of " a communication drawn up and presented to the Board of Agriculture by Henry Holland concerning the Pig method or the art of building strong and durable walls to the height of several stories with nothing but earth." Here we may say that the volume at the British Museum includes only the second and fourth issues of what was evidently a periodical publication of the Board. This is to be regretted because a reference in the introduction of the fourth issue shows that issue No. 1 contained the historic outline in regard to the Pise process. The following report upon Holland's Communication (or essay) has been prepared for us :- This essay is an English adaptation of the works of F. Cointeraux (1st and 2nd issues) from which it contains some

passages translated verbatim, and also of other French authors (Goiffon, Abbe Rozier) who wrote upon the same subject. The Communication consists of an Introduction and sixteen chapters, of which the following is a cursory summary :— Itrraonnovort.—The Communication is stated to be taken from a work by Cointeraux (1791, title not given). " The possibility of raising the walls of houses two or oven three stories high with earth only, which will sustain floors loaded with the heaviest weights, and of building the largest manufactories . . . may astonish everyone who has not been an eye- witness." The author warns his readers that the Pied method has nothing in common with the hovels built of mud mixed with straw or chopped hay to be found in some parte of England. Chapter I.—Of Pis6 and its Origin.—Merely by compressing earth m moulds or oases houses of any size or height can be built. At present (1797) the method is only practised in the province of Lyons, but it was already well known in antiquity.

Chapter IL—Of the Implements Necessary for Building.— The only special implements required are a mould and a rammer. A very detailed description of the mould is given, together with the method of fixing it upon the wall by means of joists, posts, and wedges. The mould forms a sort of oblong box narrower at the top. This box is made of deal, something more than ono inch thick, well planed, ten feet long, two feet rune inches high, and is reinforced by four ledges on each side, and provided with handles. The head of the mould which forms the angles el the building must be made of two narrow pieces of wood ecghteen inches broad and three feet high. This contrivance is initially fixed upon a stone foundation, and then upon the layers of wall already constructed by means of transversal joists provided with mortises in which the tenons of the posts are fitted and fixed

by means of wedges. The posts are fastened together at the top by. a twisted rope, so as to secure the perfect rigidity of the

mould. This chapter in the Communication, is accompanied by numerous_ plates representing the mould with all its parts, the rammer, etc. Chapter III.—Method of Working.—This chapter is descrip- tive of the method of fixing the mould on the foundation which, for cottages, should be raised at least two feet from the ground. It should be eighteen inches thick, and made of some durable masonry—stone, for instance. The joists should then be placed across this foundation, and the posts sunk in their mortises. The lateral boards of the mould are placed along tho walls between the posts, and the whole device is secured in position by wedges,at the bottom, and by rope at the top. The ten-foot mould thus obtained is divided into three compartments, each of which is worked by a separate workman. Layers of earth three,to four inches thick are spread at the bottom of the mould, trodden in, and then stamped by the rammer, at first at the sides of the mould, and then in the middle, care being taken to cross the strokes. This chapter also contains advice as to how to proceed with the angles of the house and partition walls. Chapter IV.—Method of Forming Openings. for Doors and Windows.—In leaving openings for doors and windows the same heads of the mould shictild be used as for building the angles of the house. No wood should be used in the exterior decorations of the openings, as wood never unites with Pied. Stone and brick are suitable materials. The same applies to chimney-pieces. Interior doors require no jambs, and can be hung upon the finished earthen walls.

Chapter V.—Effect of Beating Earth, Cement, or other Com- positions:—This method of beating the earth was used by the ancients for rough walls, by the Italians for building the terraces which roof their houses, by the Moors for all their walls, and by the French and Spaniards for floors. Beaten earth does not shrink or crack, The superfluous water being forced out of the earth, all the particles become closely united. The effect of this beating is similar to the process which in nature takes place. in the formation of stone ; this explains the extraordinary dura- bility of houses built of Pied.

Chapter VI.—Description of Compressed Earth.—This chapter treats of the loss of weight of, the beaten earth through evapora- tion. Upon beating a small. portion of earth it was found to weigh 39i. lbs. Fifteen days later it had boat 4it lbs. ; at the end of another fifteen days only 1 lb was lost ; and during the next fifteen days the loss of only d lb. was observed. In forty. five days all moisture had completely evaporated, and the weight of the earth was diminished by about it, consequently only of the whole mass was occupied by moisture, and this small proportion cannot effect the solidity and consistency of earth so treated. Note the difference between this process and " mud-walling " where water is added,

Chapter VII.—Contains observations on the speed with which Pled walls can be built. Three courses, each about three feet high, i.s., a wall of eight or nine feet high, or one story, can be laid upon each other in one day. The heaviest beams and rafters may be laid upon a newly-made wall, and the thickest timber on newly-made Pise gables.

Chapter VIII.—Earth Proper for Building.—All earths having neither the lightness of poor lands nor the stiffness of clay, all earths fit for cultivation, earths in fields which crack in drying, and in which mice bore tunnels of a certain regularity are suit- able for Pad. Strong earth with an admixture of small gravel is the best, therefore it is advisable to collect the earth at the foot of slopes of cultivated lands, on banks of rivers, bottoms of trenches, cellars, etc.

Chapter IX.—Mixture of Earths.—Strong earths must be tempered with light earths, those containing clay with chalky and sandy earths, glutinous with barren earths. Small pebbles or mineral (but not vegetable or animal) matter should be mixed with the earth. After two years well-worked earth with an admixture of gravel becOmes like freestone; and can "only be broken with a chisel.

Chapter X.—Experiments to Ascertain Nature of Earth.— To ascertain definitely the suitability of earth for Pis4 building

the same test by three different methods is advised. The earth

should be well rammed either in a wooden tub without a bottom, or in a mortar with an iron pestle, or simply in a wooden box. The lump of earth thus formed should be taken out and left exposed to the air, but not to perpendicular rain ; if it does not crack or crumble, but gains in density and compactness from day to day, it is good.

Chapter XL—Preparation of Earth for Building.—Well broken up earth should be thrown in a heap by shovelfuls, and any largo stones which may roll off should be removed with a rake, the teeth of which should be 11 in. apart. Only as much earth as can be used in a day should be prepared at. a time, and this should be well protected from the rain.

Chapter XII.—Bond Timber to be Used in Pis6 Buildings.— This chapter describes the manner of binding the Pise walls with rough boards 5 or 6 feet long, 1 in. thick, and about 8 in. wide, which should be laid at the bottom of each fresh course of Pis6, especially at the angles of the walls ; these, moreover, are strengthened with planks 10 or 11 in. long, laid crossways in the mould when it is half full. The wood thus incorporated with the wall is preserved from rotting, and powerfully unites the front walls to the partitions, so that " these houses made of earth alone are able to resist the violence of the highest winds, storms, and tempests." Boards 3 or 4 feet in length, placed beforehand in the Pis6 in proper places, and levelled with wedges, allow the floor beams to be laid in quite fresh Pis6.

Chapter XIII.—On Building Walls for Enclosures.—The author advocates the Pis6 method for building long walls (round parks, etc.), and for speed advises that two groups of workmen chould be employed. These groups should work from opposite ends of the wall, meet in the middle, and then work back to their respective ends.

Chapter XIV.—Time and Labour for Certain Quantities of Pis6 Building.—According to the author one skilled mason, with the help of a labourer, can build in one day 6 ft. sq. of Pis6, therefore, six men working at two moulds can build a house containing 288 sq. ft. of wall in sixteen days. Thus any one may determine the time necessary to build a house, having first ascertained the number of square feet it is to contain. If he wishes to have a wall 540 ft. long, and 6 ft. high, it can be finished

in one month by six men with one mould. " All persons, says the author, who wish to build may now contract with the builder that the work should be finished on such a date, or that he shall indemnify them for all the losses that they may incur from his failure to make good his engagement."

Chapter XV.—The Outside Covering.—The plastering of the Pise walls may be begun five or six months after the completion of the house, i.e., when the walls are sufficiently dry. For this

operation the walls should be indented with a chisel or hammer, and their surface moistened with a brush to insure adhesion.

For fixing scaffolding to the walls the little square holes left after the removal of the joists may be used. The walls may be plastered either with roughcast or stucco. A formula for pre- paring both is included.

Chapter XVL-Fresco.—This last chapter contains a formula for preparing paints to be used on freshly plastered Pis6 walls. The Communication is supplemented by a letter from Mr.

.Toucour, an emigrated French clergyman, to the Under-Secretary of Agriculture. This letter, dated June 14th, 1797, corroborates the conclusions of Mr. Henry Holland, and states that a house for one family could be completed in a fortnight. Some builders intersperse a thin layer of lime between the layers of Pis6. [The present writer recently found that this plan is practised to this day in Morocco.]

No student of Pise can help being amused by the passion with which this method of building seems to inspire its devotees. Note the violence of Mr. Holland's comments about the Pise method which " has nothing in common with the hovels built of mud mixed with straw or chopped hay to be found in some parts of England."

We wish, however, that our Public Departments could have been inspired with a little of this passion for Pise. If instead of letting their expert advisers argue about Pise, they had bought a piece of land, some shuttering and a few milliners and tried for themselves, as did the present writer, they, like the beaver in The Hunting of the Snark, would have learnt far more about Pise than all the books could teach them in thirty-five years. But Public Depart- ments like argument more than action. They are always as timid in practice as they are overflowing in writing and speech.