VOL. xin. NO. 50. 



AND GARDENER'S JOURNAL, 



397 



son Jeremiah, a lad 15 years old, jiloiighman and 

 driver ; the work was done in one hour and 

 twelve minutes, 52 furrows. Plough, Howard's 

 improved cast iron. 



Lot No. 2. Joseph G. Dumincr, of Newhury, 

 Henry Rogers, ploughman and driver : work Mne 

 in 56 minutes, with 48 furrows. 



Lot No. 3. Amos Slielden, of Beverly, Charles 

 Minot, ploughman, and driver ; work done in 

 45 minutes, with 46 furrows. Both Howard's 

 Plough. 



The Committee are of opinion that the work 

 was well done, considering the selection of land 

 and quality of soil, the land being hard and con- 

 siderably rocky, but after close inspection of the 

 work, they were unanimous in awarding the pre- 

 miums as follows, viz. 



1st to John Broklebank, of Rowley - $10 



2d to Joseph G. Dumnier, of Newbury, 8 



3d to Amos Shelden, of Beverly, - 6 



Respectfully submitted by 



Amos KiMBALL,/or the Committee. 



Rowley, Sept. 25, 1834. 



HARUENING OF LIDIK tlBIDBR WATER BY 

 ACTION OF" CARBOVATEOP POTASSA, &c. 



By A. D. Bache, Prof, of Nat, Philos Sac. Univ. Penn. 



The following experiments were made more 

 than eighteen months since, and were suggested 

 particularly at the time by the article of Professor 

 Emmett on the solidification of raw gypsum in 

 the air, by the action of the alkali, jjotassa, and of 

 certain of its salts. They commenced with an 

 examination of the effect of certain salts of potassa 

 and soda, and of caustic soda, on the hardening 

 of carbonate of lime, and of conunon lime, in 

 the air ; and by a rjatural transition, to a more inter- 

 esting subject, the effect of these, mid of other 

 materials, on the hardening of lime under water. 

 Not having leisure to prosecute this subject, I am 

 induced to ])uhlish the results already obtained, 

 that by attracting the attention of some one who 

 may be flivorably situated for carrying out the 

 course of experiment which they suggest, it may 

 be carried forward to completion. The conclu- 

 sions cannot fail to be of interest, both in a prac- 

 tical and theoretical point of view. 



It is well known that certain impure limestones 

 yield, when calcined, a lime which hardens under 

 water, technically called hydraulic lime. Exper- 

 imenters, who have examined these limestones, 

 with a view to determine the ingredii nt giving 

 this hydraulic property, have not agreed in their 

 conclusions; the essential ingredient has been in 

 turn supposed to be silica, alumina, oxide of iron, 

 and oxide of niaganese. My friend. Col. Totten, 

 informs me that Col. Troussant, in a recent work 

 on mort;u-s, attributes this power of conferring 

 hydraulic properties, upon lime, in certain cases, 

 to soda — an ingredient which, before his examina- 

 tion, had not 1 believe, been detected in any 

 hydraulic limestones. 



The method of ascertaining the effect of the 

 substances experimented upon, in causing lime to 

 harden underwater, was similar to that employed 

 by Raueourt, and described in his work on mor- 

 tai-s. The mixture having been made, and 

 brought to a paste of a proper consistency, was 

 placed at the bottom of a glass vessel, and water 

 poured gently upon it. A wire stem, terminated 

 at one extremity by a wooden disk, was placed 

 vertically upon the mixture in the vessel, and the 

 weight ascertained which was required to pierce 



the mass ; the hole thus made being filled up, by 

 tamping the mixture with a bhmt stick, it was al- 

 lowed to remain exposed to the action of the 

 water for any desiied length of time, and then 

 subjected again to a sinular trial. 



As almost all common lime is sliglitly hydraul- 

 ic, an examination of that to be used in the ex- 

 periment was first m.ade; having been slaked, and, 

 when made into a thick paste, placed at the bot- 

 tom of a wine glass, nnd water added, the test 

 stem was applied, the mixture having set, bore 

 1 oz. troy upon the head of the stem ; after an ex- 

 posure of one day, the mass bore 1^ oz. : and 

 after two days, bore 3^ oz. ; it had been so far 

 disturbed, that it would not resume its cohesion. 



This common /ime was thus shown to possess 

 feeble hydraulic properties. When mixed with 

 sand and water, so as to form a tolerably rich mor- 

 tar, the mass, after it had set, bore 5i oz. on the 

 rod, and, afYer two days, 7 ounces, which was the 

 maximum weight borne. In its mixture with sand, 

 this lime formed a mortar which was feebly 

 hydraulic. 



Sohie of this lime was mixed with caustic 

 hydrate of soda, which, however, had a portion of 

 adhering carbonate. The proportion of soda 

 added was not particularly attended to ; it was, 

 however, much less in weight than the lime. The 

 mass became so soft, that when, after tamping in 

 the bottom of the glass, water was added the test 

 rod penetrated it freely. Afler one day, the mix- 

 true bore 4 oz. troy, upon the wooden disk at the 

 top of the rod ; after another day, 5i oz., which 

 was the maximum. It recovered this strength 

 twice, by the interval of a day between the times 

 at which it was disturbed by the penetration of 

 the rod. Soda, it then appears, renders lime, to a 

 certain extent, capable of setting under water. 



Lime being made into a paste, with soda and 

 water, acquired considerable consistency in the 

 air. 



• When lime was made into a thick paste, with a 

 solution of carbonate of soda, and exposed to the 

 air, it crumbled into dust; this being mixed again 

 with water, assumed consistency at first, but sub- 

 sequently crumbled. 



Lime did not set in the air, when mixed with a 

 solution of sulphate of soda ; the incoherent mass 

 was pulverized, and reset with water, which in- 

 creased the cohesion, but not very materially. 

 Under water, the paste of lime and sulphate of 

 soda, four ])arts of lime by weight, and one of sul- 

 phate of soda, bore 9 oz. ; but on the very next day 

 lost its cohesion. 



Carbonate of potassa, mixed with lime, in the 

 proportion of six, by weight, of tlie salt, to two 

 of lime, formed a mass which crumbled in the air; 

 but, being reset with water, assumed considerable 

 cohesion. 



This same mixture had hydraulic projiertics ; 

 for 4 oz, of lime, 2 of carbonic potassa, lind 11 oz, 

 of water, being mixed and placed under water, 

 bore, after two days' exposure, 64 oz,, or 5i lbs,, 

 whicl. was all the weight which was at hand. A 

 mass of the same mixture, which had been expos 

 ec! to the air, and was but slightly coherent, being 

 placed under water became quite hard. 



An attempt was made, by reducing the propor- 

 tion of carbonate of potassa to about 12 per cent, 

 to harden the lime in the air ; but it did not 

 succeed. 



A curious effect was produced by soda, and by 

 potassa, one arbonate of lime, reduced to po'wdcr and 



after mixture with alkali and water into a paste, 

 exposed to the air. The carbonate became, in on" 

 case, harder than the original material, and rn 

 another hut little inferior to it in hardness ; in the 

 former case the experiment was made upon chalk, 

 in the latter, ui)on Carrara marble. The marble 

 had very nearly the ajipearance of the original 

 njaterial, and a cast taken from it would have had 

 a beautiliil appearance, very different from the 

 dull white of plaster of Paris. Neither of these 

 mixtures was hydraulic: and when a mass of 

 chalk and soda, which had hardened in the air, 

 was placed in water, it was completely disintegra- 

 ted. 



I had, at the time of making these experiments, 

 a quantity of silica, which had been jirejiared by 

 passing fiuo-silicic acid into water, and which, . 

 never having been heated, was still soluble, though 

 of courije, in a small degree ; after repeated wash- 

 ings, it still restored the red color of alkanet, 

 which had been i-endered purple by a feeble alka- 

 line action. This silica was mixed with lime and 

 water, so as to form a paste, and being placed un- 

 der water, would not bear the weight of the test 

 rod ; it was exposed for four days, and was softer 

 at the end of the trial, than at beginning, — Jour- 

 nal of the Franklin Institute. 



MOWIJfCJ A WAT GRAIN. 



It is desirable in mowing away grain not only 

 to guard against the depredation of vermin, but 

 also to obtain the greatest stowage. To accom- 

 plish these objects it is necessary first to lay a 

 course of sheaves round the outside the hay with 

 their buts out and close together. 



The buts of the second course should just 

 touch the bands of the first ; those of the third 

 course should lay on the bands of the second, and 

 same rule of placing the last course a little higher 

 up on the preceding one ought to be observed 

 throughout, so that the layers of sheaves should 

 have a couvex form, gradually rising from the out- 

 side towards the centre, and for this purpose, the 

 centre ought to be well filled in. By this arrange- 

 ment every layer will be a little more crowning 

 than the previous one, and so it ought to be. The 

 centre of a mow will always settle more than the 

 outside, and if the layers are made level, they will 

 soon become concave and dishing, as it is termed, 

 and theie will be a general pressiu-e of the exte- 

 rior sheaves towards the centre; of which the 

 consequence will be an unoccupied space between 

 the buts of the sheaves and the sides of the barn. 

 But if the layers of grain are of a convex form, 

 the outside sheaves will, as the mow settles, be 

 pushed back by the central ones, close against the 

 sides of the barn, upon the same principle on 

 which both sides of a log will be pressed out by 

 the force of a wedge driven between them. For 

 a similar reason, if liay be put at the bottom of 

 mow of grain, the surface on which the grain rests 

 ought to be a little crowning. But still the mow, 

 as our barns are usually constructed, will not have 

 that compactness which it ought to possess: the 

 buts of the sheaves which rests on the girts are 

 prevented by the girts from settling, so that a 

 space is left beneath them, which both occasions 

 a loss of stowage and affords a passage into the 

 ijiovv for mice. To correct this evil the girts 

 should not be more than three inches broad, and 

 further strength, if necessary, should be supplied 

 by giving them greater depth. — Western Farmer. 



