not only risked, but, what is much more, great hazard was incurred of disclosing the fraud itself, the very circumstance of watering being matter of suspicion sufficient to direct specially the officer's attention to the state and condition of the particular steeping which he found illegally watered.

The restriction of twelve days also took away from the interested maltster the mischievous means of wasting the substance of the corn, by throwing out too much vegetation, and making that light unproductive malt which actually is at this time so abundant in the market. I would therefore humbly submit it as a matter of much importance, and as a case resting upon grounds which cannot fairly be controverted, that the revenue on malt can only be protected from very extensive depredation, and the quality of the com. modity manufactured in the greater part of the kingdom preserved from a most improvident waste, by the restriction against watering the grain upon the floors being extended from its present period of nine to its former of twelve days.

What has hitherto been stated in this report is the result of my own previous experience and knowledge in the survey and manufacture of malt; but I have now to detail the various practical facts and circumstances collected on my journey through many of the most considerable malting places, and from which I am but just returned.

My first progress was into Hertfordshire, and into the north-eastern and western directions from London, where the practice of malting prevails without watering upon the floors. I visited 115 different malt-houses of this description, all in full work. The periods of steeping were generally twice a week, and the time of keeping the corn under water varied from 48 to 56 hours. This period was shorter than had usually been employed, owing to the barleys of the last year being lighter and thinner than in former years, from a want of rain at a particular period of the crop. As the barleys, however, were hardening by longer keeping, they would take more water in the cistern.

In my inspection of the numerous maltings, I paid every attention to the state of the corn in its progress through every stage. The same process uniformly prevailed at all, and the

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only

only discoverable difference was readily to be traced in the conduct of the workmen; for where the most industrious and steady men were employed, the corn was in the best condition; but the management and object of the process were at every individual house the same.

The system of malting pursued through this part of the country is simple and obvious, and contains nothing of secrecy or difficulty that can form an obstacle to its adoption in any other part of the kingdom. It consists, in the first instance, in giving the corn a due proportion of water in the cistern, according to its condition. The thinner and lighter the grain is, the shorter is its period of steeping; and the larger, drier, and bolder the barley is, the longer it is continued under water. When thrown out of the cistern it remains in the couch from 26 to 30 hours, and it is kept a day longer at a depth of from 10 to 16 inches, varying with the state of the weather. In this situation a very moderate rise of temperature comes on, which is carefully watched, and checked by turning the grain. By the fourth day the root has come freely out, and the corn is spread abroad in the floor very thin. At this time its temperature is very little above that of the air in the malt-house, and the steeping is continued to be worked in this cool state up to the eighth or ninth day, and during this cool part of the process, the root, which at first shot out straight from the corn, curls back upon it, forming a little bushy knot of curled fibres, which does not afterwards grow any longer, and rarely exceeds half an inch in length. By the eighth day the acrospire has advanced about one-third up the grain, and to promote its further progress, the grain after this period is laid a little deeper, and so gradually increased up to the kiln. The completion of the process is judged of by the acrospire having reached two-thirds, or at most three-fourths up the grain. The circumstance therefore which chiefly distinguishes this process of malting, is that of working the steepings as cool as possible during the first half of the period of operation, and gradually increasing the heat during the other half up to the kiln.

The numerous floors which I examined in every stage of

operation,

operation, bore the most unequivocal appearance of no water having been employed in working them, and yet the vegetation was regularly and steadily kept up to the kiln. I examined specially all the old floors in the last stages of the process, and even on the kiln, and found them fresh, sweet, and in an evident state of healthy vegetation; and in some instances where the grain had been some time on the kiln, the quantity of moisture, which was flying off in a thick dense vapour, afforded satisfactory testimony, that barley, when properly treated through the working process, can carry along with it a sufficiency of the cistern water for all the necessary purposes of malting.

So very evident indeed was this, that it would only have been requisite to allow the oldest floors to have lain for a proper time undisturbed, in order to their springing up into a thick green bed of living plants. I was especially attentive to this circumstance, and can now confidently declare, that the statement of Mr. Reynoldson before the committee, wherein he affirms, in such express terms, that the putrefactive fermentation formed a part of the Ware process of malting, has, in fact, no foundation whatsoever.

I conversed with a gentleman who examined the same three floors on the following day after Mr. Reynoldson's inspection of them, and who declared, that though the corn was not in good condition, owing to the warm state of the weather, and advanced season, (they were the last steepings,) yet that the vegetation was completely alive on all of the floors, and that there did not exist a single fact or circumstance in the case, which could authorise the strange account given of them. All the maitsters also with whom I conversed on the subject, ridiculed the notion that putrescence could have any share in their process, and expressed their surprise, that so wild an opinion could have been advanced or encouraged by any one.

Most of the malt-houses consist of a range of building three stories in height, of which the two uppermost are commonly boarded, and the lower one plaster. Each steeping is divided into three parts, and worked on a separate floor. The boards are warmer than the plaster, but being higher,

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higher, the grain is situated cooler on them. This, however, contrary to what is stated against it in the evidence by the watering party, produced no irregularity in the vegetation, for the corn situated the coolest is worked the deepest; and in this way, the workmen, from practice, can keep the pieces very nearly at the same temperature. I paid particu lar regard to this fact, and being provided with a thermometer, it enabled me to determine it very exactly.

The malting rooms were kept remarkably open and airy, by throwing all the doors and windows open, and allowing the wind freely to blow over the corn. In several houses even flocks of sparrows were feeding upon the floors, and so tamely as to show that they were familiar with the place, and visited it without interruption, I was already well aware of the great importance of fresh air in malting, but did not imagine that it could be so freely admitted in the process where watering upon the floors was not practised, without inducing a too great expenditure of the cistern water by evaporation.

[To be continued.]

XVIII. On Oxalic Acid. By THOMAS THOMSON, M.D. F.R.S. Ed. Communicated by CHARLES HATCHETT, Esq., F.R.S.*

OXALIC acid, from the united testimony of Ehrhart, Hermbstadt, and Westrumb, appears to have been discovered by Scheele; but it is to Bergman that we are indebted for the first account of its properties. He published his dissertation on it in 1776, and since that time very little has been added to the facts contained in his valuable treatise, Chemists have chiefly directed their attention to the formation of that acid, and much curious and important information has resulted from the experiments of Hermbstadt, Westrumb, Berthollet, Fourcroy, and Vauquelin, &c.; but the properties of the acid itself have been rather neglected. My object in the following pages is not to give a complete

From Philosophical Transactions for 1808, Part I.

history

history of the properties of oxalic acid, but merely to state the result of a set of experiments, undertaken with the view of ascertaining different particulars respecting it, which I conceived to be of importance.

I. Water of Crystallization.

Oxalic acid is usually obtained in transparent prismatic crystals more or less regular; these crystals contain a portion of water, for when moderately heated they effloresce and lose a part of their weight, which they afterwards recover when left exposed in a moist place. When cautiously heated on a sand bath they fall to powder, and lose about a third of their weight. But as the acid is itself volatile, it is not probable that the whole of this loss is water. To ascertain the quantity of water contained in these crystals I had recourse to the following method:

1. Seventy grains of crystallized oxalic acid were dissolved in 600 grains of water, constituting a solution which weighed 670 grains.

Fifty grains of pure carbonate of lime, in the state of calcareous spar, were dissolved in muriatic acid; this solution was evaporated to dryness to get rid of the excess of acid, and the residue redissolved in water.

Into this muriate of lime the solution of oxalic acid was dropt by little and little as long as any precipitate fell, and the oxalate of lime thus formed was separated by the filter. Pure oxalic acid is not capable of precipitating the whole lime from solution of muriate of lime, the muriatic acid evolved being always sufficient to retain the last portions in solution.

It was necessary to get rid of this excess of acid; the method which appeared the least exceptionable was to saturate the muriatic acid with ammonia: accordingly, when the oxalic acid ceased to occasion any further precipitate, I cautiously added pure ammonia, till the liquid ceased to produce any effect upon vegetable blues. A copious additional precipitate of oxalate of lime was thus obtained. Oxalic acid was now added again as long as it rendered the liquid muddy. By thus alternately having recourse to the