and benefit to the institution, still retains his connection with it as half-yearly ina thematical examiner. Among the other gentlemen connected with the mathema tical department, Mr. Bonnycastle and Dr. Gregory have been long known to the public by their scientific perform. ances. And Capt. Malorti, one of the fortification masters, has published some useful elementary works on the branch of knowledge he teaches. The cadets who are instructed at Woolwich were for some years sent to the Military College, then at Marlow, now at Sandhurst, as a preparatory school; but that plan being found attend ed with disadvantages, it is now aban doned. The institutions at Woolwich and Sandhurst are now therefore entirely independent; and it may be added, that they are different in their nature, and are intended for very different purposes. The institution at Woolwich is confined solely to the instruction of young gentlemen intended for the artillery and engineer service; that at Sandhurst is supplementary, and designed for the instruction of such as are destined to any other branch of the military service of Great Britain. The education at Woolwich is free of expence, except the little> incurred to purchase the first uniform; the cadets at Sandhurst pay a certain sum annually, bearing an assigned proportion to the rank of their parents, and being only free, we believe, in the cases where the cadets are orphans, or their fathers subalterns. ROYAL ARTILLERY BARRACKS, WOOLWICH COMMON. NEARER to the Thames, by about twotaken to Woolwich as soon as they are thirds of a mile, than the Royal Military enlisted, and are taught, besides the maAcademy, and on the same general ele nual and platoon exercise usually taught vation, of about 100 feet above the high- to infantry, every thing connected with water mark in the river, stand the Royal the great gun and mortar practice, the Artillery Barracks. The length of the evolutions of horse and foot artillery, the south front (of which the above is a per- passing bridges and defiles, the throwing spective view) is about $50 yards. This of pontoons across rivers, the blocking or forms one side of an extensive quadrangle, opening of roads, the use of scaling ladof which the east front commands a very ders, &c. The ground in the vicinity is fine prospect, including the rich scenery admirably suited for the purpose; for on Shooter's Hill, and the moving pic. Woolwich Common lying in part between ture on the river nearly down to North the Artillery Barracks and the Academy, fleet. These barracks contain, besides deviates so little from a plain as to suit quarters for officers and privates of the extremely well for the usual artillery foot artillery, two squares of stabling, practice, while it furnishes a good range, and accommodations for horse artillery. Behind the colonnaded recesses in the south front are, a spacious and elegant chapel, a well-furnished library, a handsome mess-room for the officers, and offices for the commandant, adjutant-general, and for the particular business of each battalion. There is also a large and elegant riding school, of which the exterior is a piece of simple though striking architecture, in resemblance of one of the temples in Stewart's Athens. These barracks constitute a distinct garrison, of which Major-General Ram say is the present commandant. The artillery quartered here form a fluctuating Mody of from 2 to 3,000 men, They are for the firing of shells running from the THE 2 THE COMMERCIAL SALE ROOMS, MINCING LANE. THE London Commercial Sale-rooms, Jately erected in Mincing Lane, are in tended to collect in one establishment all the conveniences necessary for the public and private sales of merchandize, and principally colonial produce. These public sales were previously conducted in coffee houses, frequently in small dark and inconvenient rooms; and although the private establishments of the most eminent brokers, formed for their own particular concerns, remedied many inconveniences, yet still the sales of the same species of merchandise were held at different, and sometimes distant, places, thus precluding that competition of purchasers, which is the chief induce ment of the merchant to offer his importations to public auction; and preventing buyers from having the advantage of comparison in their subsequent purchases. The building is divided into two principal parts; the front consists of an entirely new edifice, the first stone of which was laid by the lord mayor, on the 1st of June, 1811. It is 64 ft. 6 in. long, and 38 ft. 8 in. broad; with a stone front, ornamented with 6 columns of the Ionic order, adopted with little variation from the temple of Minerva Polias at Priene, as given in the Ionian antiquities. These columns are supported on pedestals, which rest on the cornice of an inferior order, composed, not of columns, but of piers, forming the ground story of the building. The spaces between the pe destals are filled up with balustres, and above the windows are 5 reliefs, executed in artificial stone by Bubb; the middle compartment represents the city of Lon don, the four others, Navigation, Come merce, Agriculture, and the Arts. The whole of the ground floor is occupied by a magnificent coffee room, at one end of which, between two scagliola columns, appear the stairs leading to the upper floors; the one pair, consisting of two public sale rooms, communicating by large double doors, and the two pair cou taining three sale rooms. The second building, behind the one already described, formerly consisted of three houses, which are now thrown into one; the lower floors are divided into a number of counting houses; the upper into five shew rooms, the largest 60 feet long, for the exhibition of goods intended for sale, and communicating by a gallery with the rooms of the front building. Particular attention has been paid to the Lights in these rooms, and by a succession of skylights sloping to the north, the perfect light of day is admitted, and the sun excluded. The space between these buildings, and that behind the latter, on the ground floor, are occupied by a number of rooms lighted in the same way, intended for the sale of sugars. The buildings and alterations were designed by Mr. JOSEPH Woods, and executed under his direction. The recent conflagration of the Custom House has occasioned great alterations in the present use of this edifice, as the opportunities it afforded for the transaction of the public business, has determined the commissioners to take the principal part of the buildings for that purpose, till the New Custom House is finished. 3 In our next, or next following Numbers, will be given 5 or 6 other new Erec tions in or near the Metropolis; and we are then in possession of a supply of various magnificent objects lately built or building in distant parts of the Empire. To the Editor of the Monthly Magazine. very early age, he might be made a good SIR, H AVING heard that GEORGE PAR KER BIDDER, seven years of age, the son of a day labourer who has a large family, has a peculiar talent for combining numbers, I sent for him, and after making a small present to gain his confidence, desired him to read a few verses in the New Testament, his class book in a school supported by Richard Holland, Esq. and found he could scarcely do it even by spelling many words; and knew not the numbers of the verses from one to ten. I then asked him how much are 16 and 9,-33 and 14,-72 and 16,-94 and 13? and he answered immediately each question with correctness. How do you make out your answer?" I don't know." What remains when you take 3 from 12,-4 from 17,-9 from 62,7 from 83,-6 from 104,-12 from 96? To each question the reply was prompt and correct. How much is 4X12,5×7,-8×9,-9 × 12,-21 × 96,18×80? The reply was as before. How many 7's are in 84-Ans. 12. 79-6,-787, -200-12? To each question he replied correctly and readily. I then asked him how many days are in two years? But here he was at a stand-did not know what a year is, or how many hours are in a day; but having the terms explained, he soon made out the hours in a week, in a month, in 12 months. When asked how many inches are contained in a square foot, he soon signified he knew neither of the terms, nor how many inches a foot contains; but with the aid of explanation, he soon made out the number 1728: and, when desired to multiply this by 12, he complained the number was too large; but having time, about two minutes, he made out the number 20736: and by close attention and examination, I discovered that, in the first place, he multiplied the thousands, hundreds, tens, and units, in rotation, and added them together, to find the above amount. I was glad to make this discovery, as when once we find he has a method of his own, however wrong, we may hope that he may be taught the true one, without in juring his retentive faculty. Not one of the terms used above does he understand, without explanation; and on every other topic, he is as ignorant as uneducated children of his age commonly are. His physiognomy is not bad, his features pretty good, and his sym. metry without fault. Were he under the guidance of a proper master for a few years, it should seem to me that at a mathematician. But, unfortunately, the P.S. The above is but a part of the boy's performance, for he was tried in pence, shillings, and pounds, and very soon stated the number of farthings in each, under 201. To the Editor of the Monthly Magazine. SIR, HE Bill lately passed for increasing the amount of the sum, by which persons were liable to arrest and imprisonment for debt, was a praiseworthy measure; and if it had been extended to twenty pounds, as originally proposed, instead of fifteen, it would, I think, have been better still; as I have always been of opinion, that the deprivation of personal liberty for debt, is not either the best way to obtain your money, or to reform the improper propensities of the debtor: for, not to mention many other cogent reasons, by personal imprisonment many a debtor is precluded from the chance, by his manual labour, of paying at all; and, the coustant and necessary introduction of Insolvent Bills, is a melancholy and farther proof of it. But it strikes me, that the introduction of this Bill for the prevention of arrests for debt under fifteen pounds, ought to be followed up with another Bill, ena bling County Courts and Courts of Couscience to take cognizance of much larger sums than they now by law can do. So that, since the passing of the Act above-mentioned, the creditor is placed in a worse situation than ever. What we want is a court which shall promptly, and with little expense, enable the creditor to sue for his debt, and obtain it without the tremendous apparatus of writ upon writ, and month upon month and year upon year of delay. In most, or all our county courts, if the debt amount to forty shillings, the cre ditor has no resource, between that sum and fifteen pounds, but a tedious and expensive method of proceeding, inju rious alike both to the debtor and the creditor; and which tedious course too frequently enables the fraudulent debtor to elude, by delays and sundry other expe dients, the justice of the law. At the same time, it furnishes a variety of wea pons to the vindictive creditor, which enable 1814.] Mr. Jennings on Arrests for Small Debts. enable him to oppress, and overwhelm with expense, many an honest and welldisposed debtor. It would redound therefore to the honour of Sir Samuel Romilly, if he would follow up the good work which he has begun, by the introduction of such a Bill. For my own part, I see no impropriety at all in admitting all actions for debt below fifteen pounds, to be tried in our County Courts, in the same manner as all those below forty shillings now are; and I see no reason to fear that justice would not be adininistered here as well as elsewhere. But, should this be objected to, why could not the Courts of Quarter Sessions take cognizance of such causes, and make orders with ease and promptitude? A cause would then never remain longer than three months undecided, unless the parties should think proper to appeal to a higher jurisdiction: which it is not very likely would ever be done. I see but one objection to the measure, which is, that the expense of recovering debts would be so much reduced, and both debtor and creditor would be saved so many pilferings, which under pretence of law they are now obliged to endure, that the unprincipled members of the profession of the law would frequently want employment; and, there fore, such will be, no doubt, ready with their artillery and great guns to oppose so salutary an improvement in our legal edifice. But, however, we will hope, that their number is few, and that their voices will be far out-weighed, as well as out-numbered, by those worthy members who do honour to the profession. That it would have the support of the country at large cannot be doubted. Many debtorg now presume upon the difficulties which lie in the way of their creditors getting their money, and consequently, take no means to pay, or fraudulently refrain from payment; and many a creditor, from the expense and distress brought upon a debtor, knowing that in obtaining a debt of five pounds, he might put him to an expense of thirty, foregoes the recovery of the debt altoge ther. But if debtors knew that they were bound to be answerable in their goods at least, at a small expense and at a short notice, for their debts, they would contract them much more warily, and pay them with more promptitude. It is the law's expense and delays which occasion the principal part, if not all, the mischief on both sides. JAMES JENNINGS. Huntspill, Jan. 28, 1814. 105 To the Editor of the Monthly Magazine. SIR, IR Isaac Newton, for the purpose of S decomposing light, made small hole in his window shutter 4 of an inch in diameter, and having placed a prism so as to refract and receive a spectrum on a sheet of white paper, perceived seven colours in the following order, viz. red, orange, yellow, green, blue, indigo, and violet. These he supposed to be pri mary colours, which when combined in certain proportions gave white or transparent light. The necessary shortness of a letter will not allow me to enumerate his experiments; I therefore refer to his Optics. That this philosopher was mistaken in supposing he analysed incident light, will appear evident from the following experiments and observations. When we look with a prism at a window, the light passes through the panes, and likewise through the prism to the eye, undecomposed, and consequently colourless; but when we look to the frames, we per◄ ceive an artificial rainbow of reflected blue, red, and yellow; any opaque substance, as a piece of black cloth or paper, when pasted on the window, will produce the same effect, and the more dense or dark, the deeper the tints or fringe. The north, or top of the paper, will be fringed with blue, the south or bottom with red and yellow rays. Now it is evident, if light were decomposed by merely passing through the prism according to the different refrangibilities of its coloured rays, that light admitted through the panes should be equally decomposed with that in the vicinity of the opaque frames. To place this objection in a stronger point of view, I made the following experiments. I cut two holes in my window shutter, one the diameter of of an inch, mentioned by Sir Isaac Newton, the other the diameter of four inches, and having darkened the room, and applied a prism, I found that the small aperture admitted light, tinged with the seven prismatic colours, which I could receive on a sheet of white paper; the larger orifice was likewise fringed round with the seven cohours, and pencils of white light passed through the centre. Here I must again ask, if while incident light were decomposed by merely passing through the prism, why was not that coming through the centre equally decomposed with that at the edges? And, however contrary to received opinion, I ain confident it is nevertheless true, that incident light has never yet been decomposed, but that all All experiments hitherto made have been on light condensed and reflected by Opaque substances. If we paste a piece of black cloth on the window, whose colour, as I have shewn in my last communication on blackness, arises from the reflection of condensed rays of blue, red, and yellow, on applying the prism a fringe of red and yellow appears at the south; this does not proceed from a decomposition of impingent or incident light striking on the edges of the cloth, but it proceeds from an actual decomposition of the condensed coloured rays of the black cloth itself. The prism decomposes these three primary colours according to the order of their different refrangibilities; and as the red and yellow rays are more refrangible than the blue, as I shall shew in my next communication, they are brought down by the prism, and the black cloth remains of a blue colour; the farther we move from the window the more refrangible the red and yellow rays become, and conse quently the decomposition is the greater. In this experiment the north of the cloth reflects blue rays, the south red and yellow, proving in the most satisfactory manner that there are but three primary colours; and as all the secondary or mixed colours can be formed of blue, red, and yellow, to call others into existence would be contrary to the beautiful sim plicity of nature, and unnecessary. it might be asked, if there are but three primary colours, how did Sir Isaac New ton produce a spectrum of seven? The following experiment will fully answer the question. Paste a slip of black paper or cloth, six inches by three, on the window; on the south you perceive a fringe of reflected red and yellow. Paste another similar strip parallel to this, at about four inches distance; on looking through the prism you perceive the north to be fringed with blue. Thus we have three primary colours nearly in contact; the yellow rays of the upper paper, being the most refrangible, come nearest to the blue of the lower paper; and if we approach them, a green is formed by their mixture; so that we can now, without any difficulty, account for five of Sir Isaac Newton's colours, red, orange, yellow, green, and blue. But By making a small hole in his windowshutter, he brought the northern and southern fringes into contact or mixture, and produced five colours with three, it now remains to account for the indigo and violet. And here I must again refer my reader to my last communication, in which I have shewn, that blackness arises from the reflection of blue, red, and yellow; which being granted, the solution of this otherwise difficult question becomes easy. The red and yellow of the southern fringe, of the lower paper or cloth, being more refrangible than the blue, were brought down by the prism, leaving the upper part of the lower edge (when illu minated by the undecomposed light coming through) blue; under the blue appeared indigo, which, as I shall hereafter shew, is composed of blue, red, and yellow, in a different state of conden sation from black. And at the bottom of all appears the violet, arising from a quantity of the red and yellow, which had been brought down, mixed with the black rays. From this experiment we might conclude that Sir Isaac Newton, by mixing three primary colours, made seven. But I am aware it might be objected that Sir C. Englefield and others decomposed incident light coming immediately from the Sun, by passing it through a prism, placed at an open window. So far from invalidating, this experiment confirms my opinions, as I shall now endeavour to prove. The prism being a semi-transparent substance, when turned in such a manner on its axis, as partly to reflect, and partly to transmit the rays of light, (for it will never decompose, if turned at right an gles to the sun) condenses and reflects fringes of blue, red, and yellow, from its angles. These fringes being carried through the prismatic planes, by the transmitted undecomposed light, inter mix and form the seven colours as already described. And as there are three angles in every prism, so there are two spectra always formed, in the same manner as three strips of paper pasted, pa rallel to one another on the window, will form two spectra. As I am extremely anxious that my opinions should rest on the secure basis of experimental inquiry, and to shew that the decomposition of light takes place at the prismatic angles, arising entirely from these fringes of reflected light, I made the following experiment. I placed a prism at an open window, through which the sun shone very powerfully, and having made a spectrum, I slowly turned it on its axis, until I separated the red and yellow from the blue; and in place of green, white light passed through the prismatic plane between the angles. I now ascertained that the red and yellow rays passed through the upper angular edge, by intercepting them with my finger placed on it, and by running my 2 : |