16 AUGUST 1851, Page 12

"BOVILL'S PATENT."

30th July 1851.

Sin—Your paper of the 19th instant only reached me on Saturday last, accompanied by a letter drawing my attention to an article on Mr. Bovill's so-called improvements in millering ; and I was exceedingly grieved to see

byTour excellent journal so glaringly trifled with in the information supplied him, as I shall now endeavour to prove to you. When I arrived at his intended explanation of the distance the meal tra- vels through the stones, (I mean the French chalk experiment,) the little hair remaining on my head almost stood erect, and I nearly dropped the paper in astonishment, doubting for a moment that it was the Spectator I was reading: however, I read on. Now, Sir, mill-stones were never in- tended to grind French chalk ; and the wonder therefore is, not that it tra- velled between the stones more than a mile before making its exit, but that it ever got out at all. Had he tried a wax candle afterwards, the distance would have been probably doubled ; then tried a tallow candle, he might have driven the stones till doomsday and never got it through at all. These several comparisons bear about the same relation to each other as that of corn and French chalk. Why not have tried nand? and he would have had that out, comparatively speaking, with the velocity of lightning. But, Sir, it is like crushing a fly on the wheel even to reply to this at all ; for not only does Mr. Bovill know nothing of the distance the meal travels, but he does not even know how to arrive at it. It needs no man of science, nor even a practical one, to prove it. Say I am now grinding fine wheat : the boy above says "All out' ; then says, "The barley on" ; and when the atone has made three revolutions, down comes barley-meal only; and I will venture to assert that it does not travel more than twenty feet. A wide difference from the mile and a quarter of Mr. Bovill's French chalk experiment. Again, suppose the wheat should be set running into the stone to supply it to grind four bushels an hour, according to Mr. Bovill's calculation, the stones would contain nearly a peck of Wheat before any of it could be discharged : but

every common miller knows that if he was to put an extra handful of wheat in the stone's eye when at her regular work, it would instantly check the speed, and be discharged from the stones in a half-ground state ; consequently, I say, if the stones contained a peck of wheat, (which they must do according to Mr. Bovill's calculation,) it would take a stone of ten tons weight and fifty horse-power to crush it : while I contend they do not contain anything like a half-pint. To prove which, let the stone be taken up at any time, and there will be found on the whole sur-

face of the stone but a very small quantity of meal, about as much as it will discharge in three revolutions. quantity Sir, had I not been able to solve that problem when only twelve of age, my. father would have been ashamed of me. Now, Sir, as to his blowing apparatus, I consider it quite unnecessary, for it can be of no other service but to help the meal to pass through the stone faster; and that can easily be done by giving the stone more drift,—that is, setting out the fur-

rows at a different angle. But it has been proved that it is necessary the meal should travel the distance it does to grind it effectually ; and the proof

is plain that Mr. Bovill's meal was ground wretchedly bad, by making so many sharps. Strictly speaking, there is nothing but bran and flour con- tained in wheat ; and he that brings it the nearest to these two points is certainly the best miller; and I fearlessly assert that Mr. Bovill's op- ponents had the best of it, if all things were fairly considered. As to carrying away the meal in small quantities, and at a slow pace, so as to cool it at once, I approve of it, as it saves a little labour, and also store-room for cooling the meal; but that is a system which has been in practice for many years in various mills : and as to his fans to suck away the dust, (or " stive,") I consider them all puff; and as I suppose both trials were carried on in one mill, I should say the puffing-fans sucked some of the other parties' best flour into his dust-bin, for I am certain the waste would never have amounted to so much if fairly done. It is stated in the article that meal ground on the ordinary plan must be kept from fourteen to twenty-eight days before it can be dressed : this is a gross error or misstatement. Meal is never kept undressed intentionally more than forty-eight hours. If the wheat is damp, three days may be required ; but a longer delay would cause it to heat of itself : this utterly disproves the statement in your article. Dressing with a flour-cloth, instead of with a machine, is the only improvement worth noticing; and even in that respect there is a great drawback : for to carry out the French sys- tem of dressing, it would take twenty flour-mills, each twenty feet long, and to be continually going, to keep clear of sixty pair of stones; consequently they would need a building nearly as large as the Crystal Palace for ma- chinery; whereas, by the old system of dressing, four ordinary machines would do the business, and equally well, if the wheat was only ground in a workmanlike manner. As to the great saving of labour at Deptford, allow use to doubt whether a good comparison could be made in a Government de- partment, where all goes notoriously slow. Some qualities of wheat, too, are ground much quicker than others: what quality of wheat was that ground by Mr. Bovill, which cost 4s. per quarter less than that ground by the ordi- nary machinery ?

When I assert that Mr. Bovill knows nothing of millming or millwright- ing, I consider it the most charitable construction to be put upon his ridi- culous assertions ; and when, too, these first principles are so viciously mis- stated against the old system, and seeing that he cannot by his own showing make much fine flour, but prefers the sharp biscuit-flour, I not only ques- tion the comparative result of his experiments at Deptford, but I also ques- tion a similar result from a mill said to have been long since in operation ; or if so, and successfully, what need of further proof ? If Mr. Bovill doubts my statement of facts, he is welcome to test them in my mill: I doubt whether his would bear the same ordeal.

During my present visits to the Great Exhibition I have not seen "Bo- vill's Patent" there. If it is so vast an improvement, why is it not in the World's Fair, where we countrymen might have had an opportunity of test- ing its merits ? A COUNTRY MILLER from Boyhood.

[We need not take the trouble to answer mere badinage. The experi- ment with the piece of chalk was only designed to give an approxi- mate quantitative estimate of an evil with the qualitative existence of which every miller is practically conversant. We could show that the ex- periment was perfectly fair, and that our correspondent has made many erro- neous statements in opposition to it; but the labour would be lost, for the experiment, though ingenious, was very unimportant. The infirmity of the old system, about which there is no doubt, is that it ground wheat very slowly, or if quickly, with such a generation of heat as to spoil the meal ; and the de- monstrated merit of Mr. Bovill's plan is that it grinds wheat at from twice to thrice the old rate, and yet delivers the meal so cool and well ground that it can be, and is, dressed instanter, and "with a flour-cloth instead of with a machine," in the mode which our correspondent notes with marked approval. He observes that an alteration of the slant of the cutting-grooves on the face of the stones would cause the meal to be shed faster : it would do so, but it would do so only by giving out corn and meal together insufficiently ground . no plan but Mr. Bovill's has ever accomplished his results ; and practical millers state to us that to accomplish them by simply altering the set of the grooves is impossible.

Our correspondent suspects that Mr. Bovill's fanners " sucked sonic of the other parties best flour into his dust-bin " : this suspicion betrays igno- rance of the process, and forgetfulness of the faCt that no other parties were milling at the same time. The great waste under the old mode results from the flour-dust or " stive" : by the new mode all of this is saved; and the atmosphere of the mill is made almost perfectly free from dust. He ob- jects, too, that the dressing-machines would occupy the space of the Crystal Palace: if they did so, they would still occupy less space than the meal which is at present necessarily kept in store for some days before it can be dressed : but they do not so. If the Country Miller will go and use his eyes, he will find the dressing-machines perfectly compact, and reasonable in size. It is asserted that our statement as to the length of time which meal must be kept before it can be milled " is a gross misstatement or error" ; that "meal is never kept undressed intentionally more than forty-eight hours." We have taken some pains to be right on this point, and find it to be note- rious among all the best millers and bakers, that the meal for making the best flour should stand the time we mentioned before being dressed. Small capitalists keep it a less time, and in doing so they send their flour to the baker before it is thoroughly cool and mellowed ; and if our correspondent's meal heats when it is kept more than three days, it is plain that his meal must be ground so hot that active fermentation is set on foot in it.

The wheat in the trial which we described was an ordinary sample of English, we believe Lincolnshire. It will be remembered, that instead of the wheat being "ground wretchedly bad," " making so many sharps,"—under the new mode it was so ground as to yield less offal and more flour by a-con- siderable percentage both in quantity and value than under the old mode. The Country Miller wisely says nothing about the fine quality, and conse- quent high price, of the flour ground by Mr. Dives of Battersea on Mr. Bovill's plan. It is plain that our correspondent has but a vague and inaccurate under- standing of the process and its results : he should go and see for himself.]