sms's; JOURNAL OP NATURAL PHILOSOPHY, CHEMISTRY, AND THE ARTS. VOL. XXXIV. Sllusttatett toftl) enjjmbtojj& BY WILLIAM NICHOLSON- LONDON: PRINTED BY G. SIDNEY, NORTHUMBERLAND-STREET STRAND, For W. Nicholson, No. 13, Bloomsbiiry Square; AND SOLD BY SHERWOOD, NEELEY, and JONES, Paternoster Row - and all Booksellers. 1813. ■XAVMXSOT. - -, ■ >& TABLE OF CONTENTS TO THE THIRTY-FOUR! H VOLUME. JANUARY, 1813. Engravings of the following subjects : A Periscopic Camera Obscura, by Dr. Wollaston, Sec. R. S. A Periscopic Microscope, by the 'same. An improved Pump for raising water, and keeping itself clear in mines or wells, during the time of sinking, bv Mr. William Brunton. I. — Comparative Analysis of the Urine of different Animals. By M. Vauquelin. - - - 1 II. — Some Account of Zerah Colburn. an American Child, who possesses some very remarkable Powers of solving Questions in . Arithmetic by Computation, without Writing, or any visible Contrivance. - 5 III. — Far her Experiments and Observations on the Action of Poisons on the Animal System. By B. C. Brodie, Esq. F. R. S. Communicated to the Society for the improvement of Animal Chemistry, and by them to the Royal Society. (Concluded from p. 268.) ~ - 9 IV. — On the Vegetation of high Mountains, translated from a Paper of Mr. Ramond's in the Annales du Museum, V. iv. p. 395. By Richard Antony Salisbury, Esq. F. R. S. &c. 16 V. — Description of a Bank for Alpine Plants, by Monsieur Thouin, abridged from his Paper in the Annales du Museum, V. vi. p. 183. By Richard Anthony Salisbury, Esq. F. R. S. &c. - - 24 VI. — On a Periscopic Camera Obscura and Microscope. By William Hyde Wollaston, M D. Sec. R. S. From the Philosophical Transactions for lbl2.p. 370. ... . - - 26 VII. — Practical Experiments on hardening Steel. By Mr. E. Lydiatt, Lecturer on metallurgy, and the mechanic Arts, &c. In a letter from the Author. - ... - -. 31 VIII. — Chemical Observations on the Sepia of the Cuttle Fish. By Mr. GroverKemp. Received from the Author. 34 IX. — On the Motions of the Tendrils of Plants. By Thomas Andrew Knight, Esq F. R. S. From the Philosophical Transactions for 1812. 37 X. — Additional Experiments on the Muriatic and Oxymuriatic Acids. By William Henry, M. D. F. R. S. V. P. of the Literary and Philosophical Society, and Phys:cian to the Infirmary at Manchester. From the Phil. Transactions, 1812. ... 42 XL — Experiments on Putrefaction. By John Manners, M. D. of Phila- delphia. In a letter from the Author. - - 49 XII. — Of the excellent Qualities of Coffee, and the art of making it in the highest perfection. By Benjamin, Count of Rumford, F. R. S. Abridg- ed from his 18th Essay, published in London in 1812. - - - 56 XIII.— Meteorological Journal. - - - - 62 XIV. — Description of an improved Pump for raising the water from Wells or Mines, while sinking or making. By Mr. William Brunton, of Butterly Iron Works, in Derbyshire. Extracted from the Transactions of the Society of Arts, published in the Year 1812. - - 64 XV. — An Account of an Experiment made in the College Laboratory, Edinburgh, drawn up by John Davy, Esq. 68 Scientific News. ------ 72 FEBRUARY, if CONTENTS. FEBRUARY. 1813. Engravings of the following subjects: l.A new Remontoire Escape- ment for a Pendulum Clock, by Mr. Prior. 2. A method of conveying steam from Boilers, by Mr. Webster. I.— An Account of some Experiments on different Combinations of Fluoric Acid. By John D?vy, Esq. From the Philosophical Transactions, 1812. .. 81 Il.-r-Obscrvations on the Measurement of three Degrees of the Meridian conducted in England by Lieut-Col. William Mudge. By Don Joseph Rodriguez. From the Philosophical Transactions for 1812, p. 321 . (Con- cluded from p. 334 . Pol. XXXI il J . . . . . . 90 III. — Critical Observations, on Dr. Wollaston's stated improvement of the Camera Obscura and Microscope in the application of the Meniscus, and two Piano-Convex Lenses ; proving their inferiority to the double Convex Lens generally used. By Mr. William J jnes, Optician 100 IV. — Rules for discovering new Improvements, exemplified in the art of thrashing and cleaning grain ; Lulling rice ;. warming rooms ; preventing ships iV>;ra sinking,, &c. By Oliver Evans, of Philadelphia 10? V. — Useful or Instructive Notions, respecting various o! jects. 1 . Multiply- ing of Copies of Writing. 2. Scintillation of tiie Stars. 3. Large Aeronaut I enses.—W. N .. .. .. .. .. 113 VI. — An Account of some Experiments on -he Congelation of Mercury, by means of Ether. By A. Marcet, Itf . D. 1 . R. S ' 1 1 9 VII. — Observations upon the best state in which it is adv.'iable to bring the British Merino Wools to market. By Edward Sheppard, Esq. of Uley, in Gloucestershire. .. .. .. .. .. . . • 121 VII L — General Results of Beccaria's Observations upon the Electricity of the Atmosphere during serene weather ; together with those of Romayne and Henley. Abstracted by a Correspondent. (R. B.) .. 126 IX. — Notice of an Adventurer to the Interior of Africa. . . 134. X. — Description of a remontoire Escapement for Pendulum Clocks, invent- ed by Mr. George Prior, Jun. .. . . . . 13(5 XL — Description of a simple, cheap, and easy method of preventing the Annoyance of steam from Boilers in Manufactories and other Places. By Mr. George Webster, of Leeds. .. .. ... 138 XII. — Meteorological Journal. . . . . . . . . 140 XIII. — An Explanatory Statement of the Notions or principles upon which the Systematic Arrangement is founded, which was adopted as the basis of an Essay on Chemical Nomenclature. By Professor J. Berzelius. 142 XIV. — Facts and Remarks upon the Interruption which the situation of the maintaining weight produces in the rate of a Clock when near the Pendulum. By H. K. .. .. .. ... 146 Scientific News. .. .. .. .. .. 148 MARCH, CONTENTS. MARCH, 1813. Engravings of the following subjects : — 1. A very simple and cheap distil- latory apparatus. 2. An instrument for ascertaining the quality of corn by its weight in a given measure. 3. A statical blow-pipe. 4. Plan of the drainage of marsh land in Yorkshire. 5. Instruments for treating the new explosive compound of chlorine and azote. I.— An explanatory Statement of the Notions or Principles upon which the systematic Arrangement is founded, which was adopted as the Basis of an Essay on Chemical Nomenclature. By professor J. Berzelius. 153 II. — Notice respecting Experiments on the freezing of Alcohol. By Mr. Hutton. 166 III. — Some Remaiks on the Use of Nitrateof Silver, for the Detection of minute Portions of Arsenic. By Alex. Marcet, M. D. F. R. S. - 174 IV. — Meteorological Journal -- - -- ------ 173 V. — On the Explosive Compound of Chlorine and Azote. By Messrs. R. Porretty jun. William Wilson, and Rupert Kirk. - 180 VI. — A statical Blow Pipe, with Remarks by C. L. - 190 VII. — Description of a simple Apparatus for Distillation. By a Correspon- dent. - - - - - - - - - --192 VIII. — Upon certain ready Processes for Computation, supposed to have been invented by the American boy exhibited in London. - - 193 IX. — On the Appearance and Disappearance of the Aurora Borealis. By M. Cotte. I96 X. — Description cf a portable Instrument for ascertaining the Quantity of Grain by Weight, called the Chondrometer. - - - - 198 XI. — Further Experiments and Observations on the Influence of the Brain on the generation of animal heat. By B. C. firodie, F. R. S. - - 199 XII. — Abstract of a Memoir upon the Origin and Generation of the electric Power, whether by Means of Friction, or in the Pile of Volta. By J. P. Dessaignes. - - - - - - - -211 XIII. — Account of the Drainage of a Piece of Morass Land, called the Tarn, in the Parish of Clapham, in Yorkshire. By Major B. Hesleden. - 218 XIV. — Respecting the Action of coloured Rays upon a Mixture of oxy mu- riatic Gas and hydrogen Gas. By Mr. Seebeck. ... 220 Scientific News. - - - - - - -- * 221 APIUI , vi CONTENTS. APRIL, 1813. Engravings of the following subjects : 1, Apparatus for experiments on ani- mal beat. 2. Apparatus for experiments on the explosive compound. 3. Delineation of a very singular figure, formed in the ice of a pond, cor- re»ponding with that of a man, who lay drowned at the depth of five feet below the ice. 4. View of the Caldeiras or boiling Fountains in one of the Azore Islands. I. Experiments on the comparative Strength of Men and Horses, ap- plicable to the Moxement of Machines. By M. Schulze 233 II. — An explanatory Statement of the Notions or Principles upon which the systematic Arrangement is founded, which was adopted as the Basis of an Essay on Chemical Nomenclature. By Professor J. Berzelius... 240 III. — A Reply to Don Joseph Rodriguez's Animadversions on Part of the Trigonometrical Survey of England. By Olinthus Gregory, LL. D. . of the Royal Military Academy, Woolwich 246 IV. — On the Existence of combined Water in muriatic acid Gas. By J. Murray, Lecturer on Chemistry, &c. Edinburgh .. 264 V. — On the Explosive Compound of Chlorine and Azote 276 VI. — Vindication of the Claims of the American Boy to extraordinary Talents and original Discovery. In a Letter from Mr. W. Saint 29 1 VII. — Meteorological Journal. ... 1 296 VIII. — On the Connection between Shooting-Stars and large Meteors, and proceeding both from terrestrial and satellitulae, in rejoinder to Mr. G. J. Singer. By Mr. John Farey, Sen 298 IX. — Account of a remarkable Appearauce in the Ice of a Pond in which a man was drowned. (W. N.) 301 X.— Of the Caldeiras or Hot Fountains of the Furnas in the Island of St. Michael, one of the Azores 305 Scientific News 30^ CONTENTS. vii SUPPLEMENT TO VOL. XXXIV. Engravings on the follow!: g subjects : A perspective View of Machinery for raising boats from a lower to an upper level upon canals, and the contrary. By Mr. Woodhouse. Paits ot the Engine given in detail. I. — An explanatory Statement of the Notion or Principles upon which the systematic Arrangement is founded, which was adopted as the Basis of an Essay on Chemical Nomenclature. By Professor J. Berzelius. (Continued from p. 246.) - - - 313 II. — Inquiries relative to the Structure of Wood, the specific Gravity of its solid Parts, and the Quantity of Liquids and elastic Fluids contained in it under various Circumstances ; the Quantity of Charcoal to be obtained from it j and the Quantity of heat produced by its Com- bustion. By Count Rumford, F. R. S. Foreign Associate of the Imperial Institute of France, &c. --- - - -- - 319 III. — Description of the perpendicular Lift erected as a Substitute for Locks on the Worcester and Birmingham Canal at Tardebig, near Bromsgrove. By Mr. Woodhouse. From a printed Letter of Mr. Edward Smith, of Birmingham, and the Reports of W. Jessop, Esq. - 335 IV. — Curious Fact of the Outlines of Trees, accurately sketched on the surface of the ice on the Bog Lakes of Ireland. In a Letter from John Chichester, M.D. of Bath. 343 V. — On Copper Wire, gilt with Brass. In a Letter from a Corres- pondent. ^ .... 344 A JOURNAL JOURNAL OP NATURAL PHILOSOPHY, CHEMISTRY, AND THE ARTS. JANUARY, 1813. ARflCLE I. Comparative Analyses of the Urine of different Animals. By Mr. Vaugiuelin*. THE only kinds of urine, that chemists have hitherto ana- Few kinds oi? Jysed in a satisfactory manner, are those of man, and some "J^6 sa^sfac- of the larger herbivorous animals. Those of the carnivorous ed. animals and glires have not yet been examined by any person that I know of. If it be acknowledged, however, that comparative anatomy Comparative has contributed much to the advancement of physiology, it will commended." also be found, perhaps, that comparative chemistry may be of great advantage to that science. i Already has the analysis of the urine of birds afforded re- ^"ne °* hirds. suits sufficiently interesting and unexpected, to induce chemists to pursue the inquiry in all animals that furnish this fluid, that we may not judge from analogy, which is frequently deceitful. It is with this view, that I have undertaken the analysis of the urine of the royal tiger, the lion, and the beaver -f the results of which I here give, till I have time to pursue my inquiry Qn this subject farther. * Ann. de Chim. vol. LXXXII, p. 197. Vol. XXXIV.— No. 156. B Urine ANALYSES OF URl-NE OF DIFFERENT ANIMALS* Urine of the lion and tiger. Points in which they differ from that of man. Ammonia. No uric acid animal food therefore not its source. Want of phos- phate of lime. Yet this is se- parated in the kidneys ; but prohably precipitated by the ammo- nia. Their calculi must he phos- phate of lime. Little muriate of soda. Much urea. Other sub- stance*. Urine of the lion and the royal tiger. The urine of the lion, and that of the tiger, are perfectly similar in every respect. They have likewise some analogy to that of man, but they differ from it essentially in some im- portant points. First difference.— They are alkaline at the very instant they are voided : on the contrary, those of a healthy man are con- stantly acid. It is to the presence of ammonia developed in these urines> that we must ascribe the strong and disagreeable smell they diffuse immediately on issuing from the bladder of these ani- mals. Second difference.*— They contain no uric acid, either free or combined with an alkali. At least the analysis of these urines four times repeated afforded me no sensible trace of it. The want of uric acid could riot but the more attract my attention, as I had considered its formation to be owing chiefly to animal food. Third difference.— The almost total absence of phosphate of lime. This might naturally be expected, as this salt is soluble in water only by the help of a superabundance of acid, and the urine in question is alkaline. It appears, however, that the kidneys of these animals sepa- rate a certain quantity of this salt from the blood, for I have found slight traces of it in these urines ; while the ammonia is formed only in the bladder, where probably it precipitates the phosphate of lime j and this is no doubt the reason why the urine of these animals is almost always turbid when voided. Hence, if calculi be ever found in the bladder of these ani- mals, they can be formed only of phosphate of lime, since they contain no other insoluble substance. Fourth difference. — The urine of the lion and of the tiger contains but an infinitely small quantity of muriate of soda, while that of man commonly affords much. In these urines we rind a large quantity of urea, much dis- posed to crystallize, and in general but lightly coloured} phos- phates of soda and ammonia ; sulphate of potash ; a mucous matter, and a trace of iron. Thes« ANALYSES OF URINE OF DIFFERENT ANIMALS. $ These are the points in which the urine of the lion and the royal tiger resembles those of man : but it differs from it, as we have seen, in a sufficient number of points, to consider it , as a distinct species. It is composed of 1, Urea, Component 2, Animal mucus, p 3, Phosphate of soda, 4, " ammortia, 5, Muriate of ammonia, 6, A trace of phosphate of lime, 7, Sulphate of potash in large quantity; 8, An atom of muriate Of soda. Urine of the beaver. A careful analysis of the urine of the beaver, Several times Urine of thi repeated, has taught me, that it has a great similitude with the urine of the common herbivorous animals. In fact, we find in it carbonate of lime held in solution by a its contents, superabundance of carbonic acid ; the benzoic and acetic acids; urea, muriate of soda, and sulphate of potash : but no uric acid, or phosphoric salt. It differs from them, however, in containing no muriate of Difference ammonia, but a notable quantity of carbonate and acetate of common" her- magnesia, which are not found, at least in any great quantity, bivorous ani- In the urine of herbivorous animals. ma s* The following is the mode in which I detected the carbonate of magnesia. After having concentrated a certain quantity of the urine by ^odem a gentle heat, I decanted the thickened liquor, and washed with which the car- distilled water the vessel, on the sides of which the carbonate nesb^vv^df- of lime had settled. I then poured in some sulphuric acid, tected. diluted with water, which produced a frothy effervescence, on account of a mucous matter, which the carbonate of lime car- ries with it. Perceiving that the sulphuric acid had acquired a bitter taste in this combination, 1 dried and calcined the mixture, washed it with a little water, and by evaporation obtained a salt, that possessed all the properties of sulphate of magnesia, B 2 Desirous * ANALYSES OF URINE OF DIFFERENT ANIMALS. Desirous of knowing by another experiment, whether the urine of the beaver, like that of all other herbivorous animals, • contained any muriate of ammonia, I put into a portion of the thickened liquor a bit of caustic potash ; and as no smell of ammonia was perceived, even when heat was applied, I con* eluded, that it contained no muriate of ammonia. But a phe- nomenon presented itself, that occasioned me some surprise, and made me desirous of discovering its cause. The liquor coagulated into a gelatinous mass. Suspecting that this effect was produced by the precipitation of some earthy substance, I treated the whole of the thickened urine I had with caustic potash j filtered off the liquor to obtain the matter in question j and after it was washed and calcined, combined it with sul- phuric acid, diluted with water, and obtained sulphate of mag- nesia mixed with a little sulphate of lime. , The acetate of Though I have said, that the urine of the beaver contains Tna^iieiia P*r" acetate of magnesia, yet I am not perfectly certain of it. It haps a pro- . .,, ,,., . i i ■«« j . duct. is possible, that during the evaporation, though effected by a gentle heat, a certain quantity of acetic acid was formed ; and that this acted on the carbonate of magnesia, remaining in the liquor in consequence of its being more soluble than the car- bonate of lime. Colouring We commonly find by the colour, smell, and taste of the juatter of its beaver's urine, and particularly by its property of dying the urine. alumed stuffs, the kind of vegetable on which it h;is fed. Instance. I" that in question I very evidently distinguished the colour- ing matter of willow bark, and its keeper afterward confirmed my observation. Properties of There are cases, theiefore, in which certain vegetable sub- vegetables not stances are capable of passing the digestive organs and the cir- stroyed in the dilation, without losing the properties that distinguish them ia circulation. their natural state. ^ Presence of * found also in the urine of the beaver a quantity of iron, iron, that at first astonished me: but on reflecting, that it had been saved in a tin vessel, and that it contained carbonic acid, I be- lieve the greater part of the metal must be ascribed to this vessel. The urine of the beaver, then, is composed of l,Urea, Component 2 . A ■ j parts of the ' ' urine. 3, Ben* COMPUTATION BY A CEIILD. 3, Benzoate of potash, 4, Carbonate of lime and of magnesia, 5, Acetate of magnesia (questionable), G, Sulphate of potash, 7, Muriate of potash and of soda, 8, Colouring vegetable matter, Q,~A little iron. Some Account of Zerah Colburn, an American Child, ivho possesses some very remarkable Powers of solving Questions in Arithmetic by Computation, without Writing, or any visible Contrivance. [The present article is copied from a printed paper, which I ob- tained from Messrs. Johnson and Co., booksellers, in St. Paul's Church-yard. This boy has been publicly exhibited in America and in London, and some time ago subscriptions were solicited for placing him to be educated under the inspection and care of several mathematical gentlemen : but I have been informed, that the plan was relinquished, from some reasons on the part of his father ; and he is again to be seen by the public. A subscription is now solicited for publishing a portrait of him on the following terms J ZERAH COLBURN, a child just eight years oj age, RemarkaM, without any previous knowledge of the common ru'e; of powers of com* arithmetic, or even of the use and power of the Arabic numerals, Plltat,onin a . child, and without having given any particular attention to the subject, possesses (as if by intuition) the singular faculty of solving a great variety of arithmetical questions by the mere operation oj the. mind, and without the usual assistance of any visible symbol or contrivance. This print will be engraved from a drawing by Mr. Trumbull -t and the size of it will be about J 2 inches by 10. The price to subscribers will be One Guinea, to be paid at the time of subscribing : and the plates will be delivered accord- ing to the order of subscription. The following gentlemen (who are well acquainted with the extra* 5 COMMUTATION BY A CHTLD. Remarkable extraordinary abilities of this child) have kindly undertaken to powers of com- attend to the progress and execution of the work, and to see to child.°n m a t,ie distribution of the plates, viz. Sir James Mackintosh ; Dr. W. H. Wollaston, Sec. R. S. ; William Vaughan, Esq. ; John Bonnycastle, Esq., Math. Prof, j Francis Wakefield, Esq. j William Allen, Esq., F. R. S. F. L. S j John Guillemard, Esq., F. R. S. F. Amer. S.; Samuel Parker, Esq. 5 Francis Bailey, Esq. Subscriptions are received by either of the above gentlemen, or by Messrs. Johnson and Co., No. 72, St. Paul's churchyard : and printed receipts will be given for the same, which must be produced and given up at the time the plates are delivered. Zerah Colburn is at present to be seen at the Exhibition Rooms, Spring Gardens. Many persons of the first eminence for their knowledge in mathematics, and well known for their philosophical inquiries, have made a point of visiting him : and they have all been struck with astonishment at his extraordinary powers. It is correctly true, as stated of him, that — " He will " not only determine, with the greatest facility and dispatch, the " exact number of minutes or seconds in any given period of time; " but will also solve any other question of a similar kind. He " will tell the exact product arising from the multiplication of '* any number, consisting of two, three, or four figures, by any " other number consisting of the like number of figures. Or, €t any number, consisting of six or seven places of figures, (t being proposed, he will determine, with equal expedition and " ease, all the factors of which it is composed. This singular " faculty consequently extends not only to the raising of powers, " but also to the extraction of the square and cube roots of the " number proposed ; and likewise to the means of determining " whether it be a prime number (or a number incapable of divi- " sion by any other number) j for which case there does not * " exist, at present, any general rule amongst mathematicians." All these, and a variety of other questions connected therewith, are answered by this child with such promptness and accuracy (and in the midst of his juvenile pursuits) as to astonish every person who has visited him. At a meeting of his friends, which was held for the purpose of concerting the best method of promoting the views of the father respecting his education, this child undertook, and com- pletely COMPUTATION BY A CHILD. P 7 pletely succeeded in, raising the number 8 progressively up to Remarkable the sixteenth power : and in naming the last result, viz. powersof com- ^ r> i » • . m t-, i putation in a 281,474,976,710,656, he was right m every figure. He was then child. tried as to other numbers, consisting of one figure ; all of which he raised (by actual multiplication and not by memory) as high as the tenth power : with so much facility and dispatch, that the person appointed to take down the results was obliged to en- join him not to be so rapid. With respect to numbers consist- ing of two figures, he would raise some of them to the sixth, seventh, and eighth power j but not always with equal facility : for the larger the products became, the more difficult he found it to proceed. He was asked the square root of IO6929, and before the number could be written down, he immediately an- swered 327. He was then required to name the cube root of 268,336,125, and with equal facility and promptness he replied 6-45. Various other questions of a similar nature, respecting the roots and powers of very high numbers, were proposed by several of the gentlemen present, to all of which he answered in a similar manner. One of the party requested him to name the factors which produced the number 24/483, which he imme- diately did by mentioning the two numbers 94 1 and 263 j which indeed are the only two numbers that will produce it. Ano- ther of them proposed 171395, and. he named the following factors as the only ones (hat would produce it ; viz. 5 x 34279, 7x24485, 59X2905, 83X2065,35X4897, 295x581, and 413x415. He was then asked to give the factors of 36083 5 but he immediately replied that it had none j which in fact was the case, as 36083 is a prime number*. Other numbers were indiscriminately proposed to him, and he always succeeded in giving the correct factors, except in the case of prime numbers, which he discovered almost as soon as proposed. One of the gentlemen asked him how many minutes there were in forty- eight years j and before the question could be written down, he replied 25,228,800) and instantly added, that the number of • It had been asserted and maintained by the French mathematicians, that 4,294,967,297 (= 292 + 1) was a prime number: but the cele- brated Euler detected that errour by discovering, that it was equal to 6,700,417*641. The same number was proposed to this child, who found out the factors by the mere operation of his mind. seconds 8 COMPUTATION BY A CHILD. Remarkable seconds in the same period was 1,5 13, 728,000. Various ques- powersofcom- tions Qf the j;ke kincj were pnt tQ him . and to a]\ 0f them he J-hiid. answered with nearly equal facility and promptitude ; so as to astonish every one present, and to excite a desire that so extra- ordinary a faculty should (if possible) be rendered more exten- sive and useful. It was the wish of the gentlemen present to obtain a know- ledge of the method by which the child was enabled to answer, with so much facility and correctness, the questions thus put to him : but to all their inquiries upon this subject (and he wai closely examined upon this point) he was unable to give them any information. He positively declared (and every observation that was made seemed to justify the assertion) that he did not know how the answers came into his mind. In the act of multiplying two numbers together, and in the raising of powers, it was evident (not only from the motion of his lips, but also from some singular facts which afterward occurred,)- that some operation was going forward in his mind ; yet that could not (from the readiness with which the answers were furnished) be at all allied to the usual mode of proceeding with such subjects : and moreover, he is entirely ignorant of the common rules of arithmetic, and cannot perform, upon paper, a simple sum in multiplication or division. But, in the extrac- tion of roots and in mentioning the factors of high numbers it does not appear that any operation can take place j since he will give the answer immediately , or in a very few seconds, where it would require, according to the ordinary method of solution, a very difficult and laborous calculation : and moreover, the know- edge of a prime number cannot be obtained by any known rule. It may naturally be expected, that these wonderful talents, which are so conspicuous at this early age, will by a suitable education be considerably improved and extended ; and that some new light will eventually be thrown upon those subjects, for the elucidation of which his mind appears to be peculiarly formed by nature, since he enters into the world with all those powers and faculties, which are not even attainable by the most eminent at a more advanced period of life. Every mathematician must be aware of the important advantages, which have sometimes been derived from the most simple and trifling circumstances ; the full effect of which has not always been evident at first sight. ACTION OF POISONS ON THE ANIMAL SYSTEM. [ sight. To mention one singular instance of this kind. The Remarkable very simple improvement of expressing the powers and roots J^p"ta^ion of quantities by means of indices introduced a new and general in a child. arithmetic of exponents ; and this algorithm of powers led the way to the invention of logarithms, by means of which a'l arithmetical computations are so much facilitated and abridged. Perhaps this child possesses a knowledge of some more important properties connected with this subject ; and although he is incapable at present of giving any satisfactory account of the state of his mind, or of communicating to others the know- ledge which it is so evident he does possess, yet there is every reason to believe, that, when his mind is more cultivated and his ideas more expanded, he will be able not only to divulge the mode by which he at present operates, but also point out some new sources of information on this interesting subject. The profits of the present print will be given to the father of this child, in order to enable him to provide a more suitable education for his son : and it is hoped that the friends of science, and the public in general, will promote a plan, which promises to be attended with such advantages. III. Farther Experiments and Observations on the Action of Poisons on the Animal System. By B. C. Brodie, Esq. F. R. S. Communicated to the Society for the improvement of Animal fihemistry, and by them to the Royal Society. {Concluded from p. 268.) IV. Experiments with the Muriate of Barytes. Baryt.es poi- HEN barytes, is taken into the stomach, or applied to a sonous, but wound, i>t is capable of destroying life j but when in its 8aits!° uncombined state its action is very slow. The muriate of ba- rytes, which is much more soluble than the pure earth, is (pro- bably on this account) a much more active poison. ' Exp 3 jyru. Experiment 5. Ten grains of muriate of barytes rubbed very fine, w JO ACTION' OP POISONS ON THE ANIMAL SYSTEM. tlat? of lury. fine, and moistened with two drops of water, were applied to re* applied to two WOunds in the thigh and side of a rabbit. In four minutes a wound in a , .,, , , . « /•• • T , rabbit. he was evidently under the influence of the poison, in a short time he became giddy : then his hind legs were paralysed ; and he gradually fell into a state of insensibility, with dilated pupils, and lay in general motionless, but with occasional con- vulsions. The pulse beat 150 in a minute, but feeble j and it occasionally intermitted. Ke was apparently dead in twenty minutes from the application of the poison j but on opening the chest, the heart was found still acting, and nearly three minutes elapsed before its action had entirely ceased, ^xp. <5. Solu- Experiment 6. An ounce and a half of saturated solution non of man- 0f nwriate of barytes were iuiected into the stomach of a full at* ot barytes , J r J . injected into grown cat, by means of an elastic gum tube. In a tew minutes the stomach of it operated as an emetic. The animal became giddy, after- ward insensible, and lay with dilated pupils, in general mo- tionless, but with occasional convulsions. At the end of sixty- five minutes, from the beginning of the experiment, he was apparently dead ; but the heart was still felt through the ribs acting one hundred times in a minute. A tube was introduced into the trachea, and the lungs were inflated about thirty-six times in a minute -} but the pulse sunk notwithstanding, and at the end of seven minutes the circulation had entirely ceased. ft appears to From these experiments I was led to aonclude, that the the brain f °n Princ,Pal action of the muriate of barytes is on the brain ; but in the first tha pulse was feeble and intermitting j in the second, although the artificial respiration was made with the greatest care, the circulation could not be maintained more but in some than a few minutes. These circumstances led me to suspect, ^egree on t ie ^^ a]th0Ugh this poison operates principally on the brain, it; operates, in some degree, on the heart also. Farther experi- ments confirmed this suspicion. In some of them the pulse soon became so feeble, that it could be scarcely felt ; and its intermissions were more frequent ; but in all cases the heart continued to act after respiration had ceased ; and the cessation of the functions of the brain was therefore always the immediate cause of death, When I employed artificial respiration, after death had apparently taken place, I seldom was able to prolong the heart's action beyond a few minutes. In one case only it was maintained for three quarters of an hour. ACTION OP POISONS ON THE ANIMAL SYSTEM. 3 1 Jiour. I never by these means succeeded in restoring the ani- mal to life, although the experiments were made with the greatest care, and in a warm temperature. In some instances, after the artificial respiration had been kept up for some time, there were signs of the functions of the brain being in some degree restored ; but the pulse notwithstanding conti- nued to diminish in strength and frequency, and ultimately ceased. I shall detail one of these experiments,* as it serves to illustrate the double action of this poison on the nervous and vascular systems. Experiment 7. Some muriate of barytes was applied to a ExP- 7- Actio* ' ... - , , . mi - .i of the muriate wound in the side of a rabbit. The usual symptoms took of -jar tes oa place, and at the end of an hour the animal was apparently tbe nervous dead • but the heart still continued to contract. He was placed svstelrTilhis- in a temperature of 80°, and a tube being introduced into the trated. nostril, the lungs were artificially inflated about thirty-six times in a minute. When the artificial respiration had been maintained for four minutes, he appeared to be recovering ; he breathed voluntarily one hundred times in a minute, and showed signs of sensibi- lity. The artificial respiration was discontinued. The volun- tary respiration continued about nine minutes, when it had ceased, and the animal was again apparently dead ; but the pulse continued strong aud frequent. The lungs were again artificially inflated. At the end of four minutes the animal once more breathed voluntarily one hundred times in a minute, and repeatedly moved his limbs and eyelids. The pulse be- came slower and more feeble. In a few minutes the voluntary respiration again ceased, and the artificial respiration was resumed. The pulse had fallen to one hundred, and was feeble. The animal again breathed voluntarily j but he ceased to do so at the end of five minutes. The lungs were inflated as before ; but he did not give any sign of life, nor was the pulse felt afterward. On opening the thorax, his heart was found to have entirely ceased acting. A probe having been introduced into the spinal marrow, it was found, that by means of the Voltaic battery powerful con- tractions might be excited, not only of the voluntary muscles, but also of the heart and intestines ; from which it may be ijiKeafie|l|c inferred, that the muriate of barytes, like arsenic, affects the it renders the circa* ACTION OF TOISONS ON THE ANIMAL SYSTEM. heart fnsensi- circulation by rendering the heart insensible to the stimulus of hie to the sti the blood, and not by destroying altogether the power of mus- mulusol' the . . bjooti cular contraction. The muriate of barytes affects the stomach, but in a less It affects the stomach, hot degree than arsenic. It operates as an emetic in animals that less thaa awe- are capable of vomiting j but sooner when taken internally, than when applied to a wound. In general,, but not constantly, there are marks of inflammation of the inner membrane of the stomach, but not of the intestine. In many instances there is a thin layer of dark coloured coagulum of blood lining the whole inner surface of the stomach, and adhering very closely to it, so as to have a good deal of the appearance of a slough ; and this is independent of vomiting, as, where I met with it, it occurred in rabbits. The same circumstances, from which it may be inferred, that arsenic does not produce its deleterious effects until it has passed into the circulation, leads to the same conclusion with regard to the muriate of barytes. V. On the Effects of the Emetic Tartar. Trneuc tamr The effects of the emetic tartar so much resemble those of kas similar et- arsenic aod« of muriate of barytes in essential circumstances, that it would be needless to enter into a detail of the individual experiments made with this poison. Applied to a When applied to a wound in animals, which are capable of wwuiid. vomiting, it usually, but not constantly, operates very speedily as an emetic j otherwise I have found no material difference in the symptoms produced in the different species of animals, which I have been in the habit of employing as the subjects of experiment. The symptoms are paralysis, drowsiness, and at last complete insensibility ; the pulse becomes feeble j the heart continues to act after apparent death ; its action may be maintained by means of artificial respiration, but never for a longer period than a few minutes : so that it appears, that this poison acts on the heart as well as on the brain ; but that its principal action is on the latter. Both the voluntary and in- voluntary muscles may be made to contract after death, by means of Voltaic electricity. The stomach sometimes bears the marks of inflammation ; but at other times it has its natu- ral appearance. I have never seen any appearance of inflam- mation. ACTION OF POISONS ON THE ANIMAL SYSTEM. U mation of the intestines. The length of time which elapses from the application of the poison to the death of the animal varies. In some instances it is not more than three quarters of an hour ^ but in others it is two or three hours, or even longer. When a solution of emetic tartar was injected into the sto- Acts in the mach of a rabbit, the same symptoms took place as when it jjJttr4Mlij„ was applied to a wound. VI. On the Effects of the Corrosive Sublimate. When this poison is taken internally in very small and re- Effects of rau. peated doses, it is absorbed into the circulation, and produces nate of m&r* cu r v . on the system those peculiar effects, which are produced by other preparations of mercury. If it passes into the circulation in larger quantity, it excites inflammation of some part of the alimentary canal, the termination of which may vary accord- ingly as it exists in a greater or less degree. When taken in a larger quantity still, it occasions death in a very short space of time. I had found, that, if applied to a wounded surface, it produced a slough of the part to which it was applied, without occasioning any affection of the general system. This led me Thev depend to conclude, that the effects of it, taken internally, and in a on its locai large quantity, depended on its local action on the stomach, ac lou" and were not connected with the absorption of it into the cir- culation. The following experiments appear to confirm this opinion. Experiment 8. Six grains of corrosive sublimate, dissolved Exp 8. Ad- in six drams of distilled water, were injected into the stomach ministered m* J ternallytojt of a rabbit, by means of an elastic gum tube. No immediate rabbit. symptoms followed the injection; the animal made no ex- pression of pain ; but in three minutes he became insensible; was convulsed ; and in four minutes and a half from the time of the injection being made, he died. Tremulous contrac- tions of the voluntary muscles continued for some time afterward. On opening the thorax, the heart was found to have, entirely ceased acting, and the blood in the cavities of the left side was of a scarlet colour. The stomach was much distended. The pyloric and cardiac portions were separated from each other by a strong muscular contraction. The con- tents of the former were firm and solid, and in every respect resembled u ACTION OF POISONS ON THE ANIMAL SYSTEM. Experiment repeated. Similar effects on the sto- mach of a dead rabbit. Etp. 9. Mil- riate of mer- cury given to a cat. appearances o:\ dissection. resembled the usual contents of the stomach j while those of the cardiac portion consisted of the food of the animal much diluted by fluid j so that the solution, which had been injected, appeared to be confined to the cardiac portion of#the stomach, and to be prevented entering the pyloric portion by the muscu- lar contraction in the centre. In the pyloric portion of the stomach the mucous membrane had its natural appearance j but in the cardiac portion it was of a dark gray colour, was readily torn and peeled off j and in some parts its texture was completely destroyed, so that it appeared like a pulp, on removing which the muscular and peritoneal coats were exposed. The repetition of the experiment was attended with similar results. The alteration of the texture of the internal mem- brane appears to have been occasioned by its being chemically" acted on by the corrosive sublimate injected into it. When the injection is made into the stomach of a dead rabbit, pre- cisely the same effects are produced, except that, as the middle contraction is here wanting, the appearances are not confined in the same degree to the cardiac portion. Experiment g. A scruple of corrosive sublimate, dissolved in six drams of distilled water, was injected into the stomach of a full grown cat. For the first five minutes no symptoms were produced. After this, the poison operated twice as an emetic. 'The animal appeared restless, and made expression of pain in the abdomen. He gradually became insensible, and lay on one side motionless, with the pupils of the eyes dilated. The respiration was laborious, and the pulse could not be felt. Twenty-five minutes after the poison was injected, there was a convulsive action of the voluntary muscles, and death ensued. On opening the thorax immediately afterward, the heart was seen still contracting, but very feebly. The stomach was found perfectly empty and contracted. The mucous membrane was every where of a dark gray colour. It had lost its natural texture, and was readily torn and separated from the muscular coat. The internal mem- brane of the duodenum had a similar appearance, but in a less degree, for nearly three inches from the pylorus. In the situa- tion of the.pylorus the effects of the poison were less apparent than in any other part. The ACTION OF POISONS ON THE ANIMAL SYSTEM, 15 The particular state of the internal membrane of the sto- mach, in this experiment as well as in the last, appears to have been occasioned by the chemical action of the poison on it. When 1 injected a solution of corrosive sublimate into the Effects on the stomach of a dead cat, and retained it there for a few minutes, yorT}a(\ °- * dead cat simi- a similar alteration of the texture of the -internal membrane lar. took place ; but it assumed a lighter gray colour. The differ- ence of colour may be explained by the vessels in the one case being empty, and in the other case being distended with blood at the time of the injection being made. The destruction of the substance of the internal membrane The nvrian of the stomach precludes the idea of the poison having been on tlie sto/ absorbed into the circulation. We must conclude, that death mach ; was the consequence -of the chemical action of the poison on the stomach. This organ, however, is not directly necessary to life, since its functions, under certain circumstances, are suspended for hours, or even for days, without death being produced. Although the stomach was the part primarily af- but produce* fected, the immediate cause of death must be looked for in d^ath l)y uu]v~ recti y destroy ilut cessation of the functions of one or more of those organs, ing the func- the constant action of which is necessary to life. From the scar- *,ons of *}** heart sivd let colour of the blood in the left side of the heart, in the expe- braia. riment on the rabbit, we may conclude, that the functions of the lungs were not affected j but the affection of the heart and ferain is proved by the convulsions, the insensibility, the affec- tion of the pulse in both experiments, and the sudden cessation of the heart's action in the first j and we may therefore be justified in concluding, that the immediate cause of death was in both of these organs. As the effects produced appear to have been independent of absorption, we may presume, that the heart, as well as the brain, was acted on through the me- dium of the nerves. That a sudden and violent injury of the stomach should be capable of thus speedily proving fatal, is not surprising, when we consider the powerful sympathy between it and the organs on which life more immediately depends, and the existence of which many circumstances in disease daily demonstrate to us. VII. The facts which have been stated appear to lead to the General ief*. following 1(> VEGETATION OF HIGH MOUNTAINS. rences respect- Allowing conclusions respecting the action of the mineral pol- ing the jK-ion i0n8 which were employed in the foregoing experiments, of these mn«- , ! / ,...*•_ j ral poiNAft. ] • Arsenic, the emetic tartar, and the muriate ot barytes, do not produce their deleterious effects until they have passed into the circulation. 2. All of these poisons occasion disorder of the functions of the heart, brain, and alimentary canal j but they do not all affect these organs to the same relative degree. >. Arsenic operates on the alimentary canal in a greater degree than either the emetic tartar, or the muriate of barytes. The heart is affected more by arsenic than by the emetic tar- tar, and more by this last, than by the muriate of barytes. 4. The corrosive sublimate, when taken internally in large quantity, occasions death by acting chemically on the mucous membrane of the stomach, so as to destroy its texture j the organs more immediately necessary to life being affected in con- sequence of their sympathy with the stomach. Mineral and jn making the comparison between them, we observe, that vegetable poi- sons om- the effects of mineral, are less simple than those of the gene- pareJ. rality of vegetable poisons ; and when once an animal is affected by the former, there is much less chance of his recovery, than when he is affected by the latter. IV. IV. On the Vegetation of high Mountains, translated from a Paper of Mr. Ramond's in the Annates du Museum, V. 4, p. 395. By Richard Anthony-Salisbury, Esq. i<\ R. S. &c*. AN observing gardener, on ascending the high mountains of our temperate region, is immediately struck with the vi- mountain in gour and luxurious appearance of their vegetation. The plants he temperate re- jias geen m tjie adjacent plains are changed in size, aspect, and form, so that he hardly recognises the most common. Their . stems are elevated, their flowers larger, even the leaves of the trees have acquired a size, which makes him doubt the identity * Hort. Trans, vol. I, appendix, p. 15. of the VEGETATION OF HIGH MOUNTAINS. 1/ of ihe species. The woods are more impenetrable, the turf of the downs closer, and a green more lively, fresh, and brilliant, colours every thing, from the depths of the valley, up to those heights, where the eye can discern nothing but naked rocks and eternal snows*. Thus, endowed with a vigour elsewhere unknown, vegetables ?£]*[£ °^T* there hasten with increased energy through the various periods of their existence. Time, which to them moves slowly in the plains, in the mountains flies. There, every thing is done rapid- ly -, meteors dart after each other, and the air is in perpetual agitation. From all these controlling causes, acting together in full force, germination, florescence, and fructification take place almost simultaneously. Sometimes, with a wind blowing from the souih, with a heavy shower, or with a scorching sun, the face of the meadows, downs, and forests, in a moment changes, and the whole of a particular species seems to vanish ; in fact, there, every fine day is a spring to some particular as- semblage of vegetables, or to some of the inaccessible heights in which they grow. To this picture, another succeeds. If we examine the moun- Their localme* j II- i L i- m j -A nl0re distinct, tains and valhes, every place has its peculiar soil, every dirrer- ent elevation its peculiar climate, and each of them its charac- teristic vegetables. In the plains, these vegetable assemblages occupy vast spaces, the limits of which are too extensive, and indeterminate, to be easily perceived. On the contrary, in the mountains, they are confined to narrow limits, which the eye often takes in at one view. In a gentle rising extended between two dales, in a pile of rocks, or in a cliff, which the traveller ascends in a few moments, he finds the perpetual barriers of those productions, which nature has been pleased to separate. Among the various causes of these separations, one seems to Part,cuJar. g* * The first part of this sentence rather applies to purely mountainous plants, such as aster alfinus, viola grandijivru, uquilegia vulgaris, &c, than to all vegetables indiscriminately; the latter part I should explain by saying, that the foliage of the trees was rather diminished in the dry plains at the base of the Pyreiu est than enlarged by mere elevation, but, along with elevation, to a certain extent, perpetual moisture and food are washed down to their roots; and such a situation in France, is pro bably the aboriginal one of the trees in question. Sec* Vol, XXXIV.— No. 156, reign. ]8 VEGETATION OP HIGH MOUNTAINS. reign predominant over all others j this is, elevation above the level of the sea. In every 100 inches in height, the temperature falls about half a degree of our thermometers. After that de- gree of cold, which generally puts a stop to all vegetation, an eternal frost prevails on the summit of these Alps, as at the 100 yards poles, and every 100 metres of vertical elevation, corresponds vaTent uTa dc- nearty to one degree of the distance at which the mountain is gree of lati- placed from the pole. J" e* By this scale, the various phenomena of different climates in Two causes of , , , .. - . . .. _, thedistribu- our globe may be easily understood : circumstances may differ, tion of vege- but the general results will be nearly the same. While the in- crease of cold is accompanied by a diminution of the column of air, it is also affected by the obliquity of the rays of the sun, and the distribution of vegetables, in all alpine countries, depends principally on these two causes. Trees. Thus, in the Swiss Alps, and Pyrenees, trees cease to grow at about 2-400 or 2500 metres of actual elevation, as they do about the /Oth degree of north latitude j and that circle these gigantic vegetables occupy, is divided into several less bounds, which have each their peculiar characteristics. At the foot of the mountain we find the oak : in the middle region the beech : above these the^r and yew succeed, which soon give place to the pine (Pinus sylvestris L.). Along with this last mentioned tree, in the Swiss Alps the larch and cembro (Pinus cembra L.) also grow wild, which are unknown in the Pyrenees. The cedar of JLebanus would probably thrive as well on these mountains, as on those of Asia, had it been fixed there j but such is still the mystery of the ori- ginal dissemination of vegetables, that Nature seems by turns, indifferent to the similitude of places, or to the distance between them j sometimes bringing together in the same climate, plants of the most distant countries j and sometimes denying this con- formity of vegetables to regions exactly alike, both in soil and temperature. Jthododen- In tu's zone of trees, the rhododendron ferrugineum L. a little dron. . shrub peculiar to the mountains of Europe solely, is very abun- dant. It never descends into the plains, and can hardly be cul- tivated In a garden, demanding its native air, soil, water, nay snows, and even there only occupies particular spots. Nothing is more beautiful when in flower, but nothing is more untrac- table. In the Pyrenees it first appears at exactly 1600 metres of VEGETATION OP HIGH MOUNTAINS. ] O, ©f elevation, stopping as precisely at 2600 melres, and within these limits, is so abundant and vigorous, that it would be as difficult to extirpate it there, as it is to cultivate it elsewhere*. The juniper traverses far beyond this circle, up to the elevation Juniper, of 29OO metres, but this shrub, as it ascends, gradually loses the habit and nppearance, which distinguish it in our plains : there, it resembles the juniper of Sweden and Lapland, with a low spreading stem, prostrate on the ground, seeking an asylum, as it were, by instinct on those sides of the rocks exposed to the south or wesu, against which it spreads out its branches into an espalier, with a regularity which art can seldom attaint- In a more elevated region, we find the rigour of the climate Annuals will not permit the existence of ajw shrub whatever, which the scarcely found - r J at a certain first snows do not entirely cover. Still higher, even this shelter height. is insufficient, and nothing but a few herbs, with perennial roots actually under the earth, subsist. Nature has almost en- tirely banished from such places annual plants ; where the whole summer is reduced to a few days, nay, sometimes a few hours ; where often a storm of wind, or dripping fog, will destroy the flowers which have scarcely blossomed, and, bringing back winter, terminate the year. On the contrary, hardly any elevation seems to stop the pro- Hardy peren- gress of some perennials, which, on the approach of severe cold, nia!s- shelter themselves under the double protection of the earth and snow, forming their buds underground, and springing up the first fine day of the succeeding year. Their duration exhausts the chances of all times and seasons, till, sooner or later, they also ripen seed, by which they are multiplied. Thus the vegetable zone of our alps has in fact no other limits, piants at the than those of the earth or soil covering them. The Picdu Midi, height of S278 which I hafe ascended 26 times, is 3000 metres above the level ^&rd9> of the sea, but I never once found the thermometer there rise to the temperate point. Yet, on a nearly bare rock, I have there gathered as many as 48 species of vegetables, excluding crypto- gamous plants: of these, one only, which perhaps I may never * No shrub is more plentiful, or easily cultivated in the gardens about London, if planted in light sandy peat under a rock, or north-west wall, and watered plentifully in dry weather. — Sec. T Two distinct species are probably here confounded, an opinion in Ti(hich I was confirmed by the late Mr. Dryander. — Sec, C 2 find £0 VEGETATION OF HI6H MOT7TS"TAINS. at 35J2 yards, find again, was annual. At Nieuville, a place 250 metres higher than the Picdu Midi,\vhere the thermometer in summer never \ rises to more than S degrees, I have, in five journies, collected at 3825 yards, j 2 different perennials. On the top of Mont Perdu, at an eleva- tion of 3500 metres, even in the bosom of permanent snows, but on rocks the sloping situation of which had cleared them of snow, I have seen six different plants very vigorous. Here, in one of the hottest days of a summer remarkable for its heat, the thermometer only rose to 5*5° above the point of congelation, and it undoubtedly falls in winter to 25 or 30 : nor is it certain, that those 6 plants, found in a season which melted more snow than usual, are regularly uncovered every year. Besides, I have seen some of them on the borders of the perpetual snow, with only half of their stems exposed and vegetating, the other half buried in it*, and it is probable, that many of them do not see the light ten times in a century, running through the whole course of their vegetation in a few short weeks, and doomed afterwards to sleep through a winter of many years. These plants Plants subjected to so singular a mode of existence are not mountains! or arnonS tne species which grow in the plains of our temperate re- the vicinity of gions : they belong exclusively tosuch as grow on the summits of the poles. mountains, or near the poles. Norway, Lapland, and Greenland, ■ furnish plants analogous to those of the Swiss Alps and Pyrenees j but few, or possibly none of them, are seen in Siberia, Kams- chatka, or even in the polar regions of America. One would hardly have supposed so great a diversity of vegetable produc- tions in countries so much alike and near each other, nor on the other hand, so great a conformity as exists among the plants of these countries, and the plants of some alpine regions distant from them 40 degrees. Plants not dls- *n ^act' we *earn ^rom actual observation, that the dissemi- seminated in nation of vegetables is not always regulated in parallel distances tudefe.6 atl" fr°m ^c etlliator J tnat V a certain number of plants, confined by their constitution to a peculiar climate, are to be found to a certain distance under the same latitudes, many others, on the * A similar case occurred in a vine at Chapel AlUrton, planted in the open air, at some distance from the stove ; a branch of which, however, being introduced into the stove early in January, was loaded with cluster* «f grapes, before any of the buds exposed to the open air, shot out. — See. con* VEGETATION OF HIGH MOUNTANS. 2K contrary, have been scattered over different countries in the di- rection of their meridians. Towards the south, America, Africa, and Asia ; towards the north, Europe, Asia, and America, are far from producing the same vegetables under the <-ame paral- lels ; while many plants, growing wild in each of these grand divisions of the globe, brave every obstacle opposed to them by a diversity of climate, and propagate themselves in a geogra- phical direction quite contrary to that which a similar climate would confine them to. Thus, for example, many of the curious plants of Sardinia, Progress of Sicily, and Italy, mount up the Swiss Alps, and then descend p"^™8 again into the lower parts of Germany, without being allured by our fine climate to France. Thus, likewise, the Pyrenees receive from Spain a great number of the plants of Barlary, scattering them over the western provinces of France. The merendera, which grows in the north of Africa, is found in Andalusia, Castile, Arragon j when crossing the Pyrenees it de- scends as far as the Landes de Bourdeaux. The narcissus hul- locodium*, and hyacinthus serotinus, grow wild in the same places, and follow the same route. The anthericum licolorum of Algiers, traverses the same chain of mountains, and arrives in Anjou. The scilla umhellata and crocus nudijlorus, have migrated from the Pyrenees even into Eng'and. Yet not one .of the above mentioned vegetables have been disseminated late- rally, to meet those southern ones which have crossed the Swiss Alps. But it is in the great valleys of the Pyrenees, extending from This most north to south, that these vegetable galaxies become most 8tr'lcing in *ne valleys of ths striking and singular. The dianthus super bus runs through the pvrenees. whole valley of Campan and Gavarnie,w'ithom ever entering any * Here the celebrated author confounds three very distinct species. *p.i snecV* The plant of the Pyrenees is the AT. Bulbocodium L. with erect leaves, confounded b^ very hardy, and brought forced to Covcnt-gurden in abundance every the author, spring. The plant of Bavbavy and Andalusia, which I received from the late professor Broussonet, is more dwarfish, with leaves spreading flat on the ground, and so tender, that it will only live here through winter, in very warm sandy soils, close to a wall. The plant of Castile grows also near Oporto, and differs from both the others, in having a six-lobed plaited crown, with very narrow leaves ; it is not very tender, but requires a dry sandy soil. Sec. VEGETATION OF HIGH MOUNTAINS. Box. Verbascum 0f {^e s\^e ones »r;he verbascum Mucoid, that beautiful and Mycom. scarce plant, which does not belong either to the genus in which Linneus has placed it, or perhaps to any natural order yet defined, and which has so exotic an appearance, that it distinguishes itself like the kingfisher, among our indigenous birds, invariably keeps to the same direction. Nothing is more abundant in all the great valleys of the Pyrenees, in every soil and exposition : yet the very same soil and exposition never attract it to any of the collateral ones. I could cite a multi- tude of similar examples, but it is sufficient at present, to men- tion one more, the box tree. This shrub, so very robust, is affected by elevation like the most delicate ones. At the base of the Pyrenees, both on the French and Spanish side, it covers every hill : thence it enters the great valleys, running from the north-east towards the south, but never quits them ; in .vain do the numerous branches of these valleys offer it an asy- lum ; passing their openings, it keeps to its first direction, stopping on the crest of the chain at about 2000 metres above the level of the sea, and appearing again on the other side at a similar elevation, and in a similar direction, from which it never deviates. Thus it is, that in high mountainous countries we discover the strongest traces of the original design of nature ; there, each order of vegetables is confined within narrower bounds j, there, local influence more powerfully resists every other. Ne- vertheless, the lapse of ages, and especially the presence of but even here man, has here introduced many modifications ; for, in tra- mochfied by versing the immense deserts of these high mountains, among the rare plants which form their herbage, some few of the commonest here and there occur. If the verdure takes a deeper tint than usual, contrasted with the gayer colour of the alpine turf, the ruins of a hut, or a rock blackened by smoke, explain the mystery. Around these asylums of man, we find naturalized the common mallow, nettle, chickweed, common dock . A shepherd had possibly sojourned here some weeks, and, hither, in driving his flocks here, had also attracted with- out knowing it, the birds, the insects, the seeds of the plants of his lowland cot. He may possibly never return, but these wild spots have received in an instant the indelible impression of Local influ- ence striking in mountain- ous coun- tries, VEGETATION OF HIGH MOUNTAINS. 23 of his footsteps $ so much weight has a being of his impor- tance in the scale of nature. In other places, by destruction he has signalized his presence. Woods de- Before he approached the mountains, the immense forests ^.r°ye 7 which covered their bases have fallen under his axe, for woods are not the abodes of man ; he avoids the circuitous paths of so vast a labyrinth, suspecting danger under their shades ; he there mourns the absent sun, an object which every day reno- vates his delight j and therefore it is seldom that he penetrates a forest, without fire and sword in hand. Accordingly the seeds of woodland plants become dormant arid with them in a soil now dried by the sun and wind, and no longer suitable w.°° an to their germinating. Other vegetables take their places, the climate itself changing $ for the temperature rises, the rains are less frequent, but more copious, the winds more incon- stant and impetuous, deep gullies are formed in the sides of the acclivities by torrents, and rocks are/ deprived of the earth which covered them, and, at the same time, of the plants which ornamented them, by falls of immense loads of melting snow ; thus the face of the globe, where man inhabits, is more changed in one century, than in twenty where he is absent. After all, in Alpine countries, the different soils, and their The horticul- productions, retain most of their aboriginal character: there, ^sital'pine the primitive distribution of vegetables has been least disturbed 3 countries as their localities can be easily traced, the influence of the air is ™elI.a* the Se" most perceptible j there, the contiguity of objects exhibiting more forcibly their similitudes and dissimilitudes, the eye of the observer takes in, at one glance, every trait which is interesting $ and if it is necessary for the geologist to visit these grand chains of mountains, to study the structure of the earth and those ca- tastrophes, which have imprinted its present form, it is still more so for the horticulturist, who wishes to penetrate the mys- teries of the primary dissemination of vegetables and their sub- . sequent propagation, hoping thence to derive hints for their successful cultivation and improvement, in the paradise sur- rounding his dwelling. 24 BANK. FOR ALflNE TLANTS. IV. Description of a Bank for Alpine Plants, by Monsieur Thouin, abridged from his Paper in the Annales du Museum. V. 6, p. 183. By Richard Anthony Salisbury, Esq.F. R. S. kc* Bank for the culture of PLANTS from alpine and frozen countries are cultivated in the Jardin des PLantes at Paris, ma bank, 60 feet long, in the botani- placed against the wall cf a terrace, 10 feet high, which faces Paris. • tDe south-east so much, that the sun ceases to shine upon it between 10 and 11, A. M. This bank is divided into 5 steps, 1 foot wide, by nailing planks of oak, 10 inches deep, to the top of as many rows of strong posts, charred at the bottom, and driven firmly into the ground ; the taller posts are still fur- ther secured in their places by cross bars let into the wall. Through the whole length of this bank runs a ditch, 2 feet deep, but sloping gradually towards the front up to 9 inches in height, under* the general level of the ground ; and in making this ditch, its sides were plastered 6 inches thick with mortar of brick mould and chopped straw ; filling up all the cracks which appeared during the week it was left exposed to the aiu. After nailing the planks to the posts, the natural soil, which is of a light nature, was thrown*into the hollow up to within about a foot of the surface of the slope, above which it was filled with sandy peat, such as ling and heaths grow in, passed through a screen. My reason for using all these precautions was topre- Vent the water necessary for the health of those alpine plants in summer, running off too quickly into a bed of dry gravel un- derneath j in a naturally moist soil, this expense and trouble may be saved. Seeds sown in I have sown on this bank the seeds received not only from r* the Alps, but several other frozen regions j for it is probable, that the elevation of the atmosphere near the poles corresponds with that of the highest mountains in France, rising gradually toward the equator -7 nor is this consideration so foreign to the business of a gardener in naturalizing vegetables, as might be at first supposed. * Horti. Trans, vol. I, appendix, p. 24. Roots BANK FOR ALPINE PLANTS. 25 Roots of all the alpine plants I could collect, have also been Roots planted- planted in this bank, and they thrive much better than uiien cultivated in pot* on a stage, however open or airy, so that most of the following have greatly increased both by seeds and roots. Moehringia muscosa, viola bi flora, androsace carnea, Catalogue. and lactea, soldanella, alpina, primula farinosa* tussilago, alpina, artemisia glaciqlis, salix myrsinites, retusa, and reti- culata. The culture they require is, 1st, to keep the lank carefully Management, weeded : 2dly, to reduce within bounds many that grow and spread rapidly so as to exclude others : 3dly, to dig and lighten the surface frequently, that it may absorb air and w^ter more readily : 4thly, to add three inches in depth of fresh sandy peat every year, in place of the old, which soon loses its humus, or nutritious part : 5thly, in giving the plants, at a certain season, not only daily, but hourly waterings ; but this being one of the most important points, I shall enlarge more fully upon it. Almost all alpine plants are of humble stature, growing on Alpine plants steep declivities of rocks in a layer of humus or vegetable earth, naturally wa- formed by the decomposition of jungermannias, lichens, and meltin/snow*. mosses. The greater part of the year, they are covered with a bed of snow, which only begins to melt at stated periods of the day, after the rays of the sun have acquired great force. Then only do these alpine plants awaken from torpidity, exhaling quickly in this light black soil the moisture which they have absorbed during the night j but the returning sun, which excites them to action, also melts the snow above, the waters of which trickling down to their roots, give immediate refreshment. The sun disappearing, these little vegetables are no longer ex-: hausted, and a continuance of moisture would even be hurtful $ accoidingly the snow resuming its solid consistence with the cold of the night, this natural irrigation ceases, with a degree of exactness, that the most careful gardener cannot perform. From the above remarks, it will easily be deduced, that alpine Artificial wa- plants should have no wa^.r at all during winter and dank tering. moist weather : on the contrary, that they should be kept per- * I have constantly found this plant growing wild in wet meadows that are seldom dry even in summer, at the foot of the mountains, and even in bogs. Sec. petually £fj PERISCOPIC CAMBRA AND MICROSCOPE. petunlly moist during hot sunshine, by water dribbling through the soil to their roots, without wetting their leaves, which, im- mediately evaporating by the heat, will cool the air just above them. In fact, it is only by a close imitation of the process of nature, that these vegetables of cold regions can be successfully cultivated in botanic gardens. They must be The last essential nont relative to a/pine plants is to cover covered from , r . / r frost. them up on the approach of frost : this may appear a strange precaution to some, bin when winter commences in their native • soil, being immediately covered with snow to the depth of seven inches, they never feel a greater degree of cold than that of the freezing ppint, the soil itself being hardly frozen. The best covering is that of fern, pteris aquilina, which does not absorb moisture so quickly as most other sorts of haulm. V. On a Periscopic Camera Ohscura and Microscope. By Wil- liam Hyde Wollaston, M. D. Sec. R, S. From the Philosophical Transactions for 1812, p. 370. Periscopic im- A LTHOUGH the views which I originally had of the ad- provement of x^L vantage to be derived from the periscopic construction of the camera. ° i spectacles*, naturally suggested to me a corresponding improve- ment in the camera ohscura, by substituting a meniscus for the double convex lens, I have hitherto deferred making it known to others, except as a subject of occasional conversation. Themathema- Since in vision with spectacles, as in common vision, the ti^al conside- pencli 0f rays received by the eye in each direction is small, ration applied1" . f . '. * / . . to spectacles is the superiority of that form or glass, which disposes all parts not with con- 0f ft m0st nearly at right angles with the visual ray, admits of plicable to the distinct demonstration j but with respect to the camera ob- cam. ob8. scura, where the portion of lens requisite for sufficient illumi- nation, is of considerable magnitude, although it is evident that some improvement may be made in the distinctness of oblique images on the same principles, yet as the focus of oblique rays is far from being a definite point, the degree in which it may be improved is not a fit subject of mathematical investigation. * Phil. Magaz. Vol. XVII. Nicholson's Journal, VII. 143. I have PBRISCOPIC CAMERA AND MICROSCOPE. 27 I have therefore had recourse to experiments, in order to Experiment determine by what construction the field of distinct represen- Preferable- tation may be most extended j and I trust the result will be acceptable to this society. I shall take the same opportunity to describe an improvement in the construction of the simple . - •_ microscope, which may also be termed periscopic, as the ob- croscope. ject of it is to gain an extension of the field of view, upon the same principles as in the preceding instances, namely, by occasioning all pencils to pass as nearly as may be at right angles to the surfaces of the lens. The mode, however, in which this is effected is apparently somewhat different in the practical execution. In the common camera obscura, where the images of distant In the corn- objects are formed on a plane surface to which the lens is J^sideTmages parallel, if the surfaces of the lens be both convex, and equally are indistinct, curved (as in fig. 1,P1.I); and if the distance of the lens be such, that the images formed in the direction of its axis CF be most distinct, then the images of lateral objects are indistinct in a greater or less degree, accordingly as they are more or less remote from the axis. The causes of this indistinctness may because the be considered as twofold ; for in the first place, all parts of plane is m«re Al , , ■. . . L ,1. distant than the plane, excepting the central point, are at a greater dis- t^e princjpai tance from the centre of the lens, than its principal focus j and focus, secondly, the point /, to which any pencil of parallel rays, q"i ,qUe pen- passing obliquely through the lens, are made to converge, is cils have a fo- less distant than the prin«ipal focus. On this account, it is in £us 8tlU short" general best to place the lens at a distance somewhat less than that which would give most distinctness to the central images, because in that case a certain moderate extension is given to the field of view from an adjustment better adapted to lateral objects, without materially impairing the brightness of those in the centre. The want of distinctness, however, is even then only diminished in degree, but is not remedied. The construction, by which I propose to obviate this defect, New construc- is represented in the second figure, in which are seen the essen- tion- Witn a ,. , ~ .1.1 . meniscus lent tial parts or a periscopic camera in their due proportion to concave to- each other. The lens is a meniscus, with the curvatures of wards the its surfaces about in the proportion of two to one, so placed aperture at a*0 that its concavity is presented to the objects, and its convexity distance from toward the plane on which the images are formed. The f^01"*™ aper- r& *ERISC0PJC camera and microscop*. aperture of the lens is four inches, its focus about twenty-two. There is also a circular opening, two inches in diameter, placed at about one eighth of the focal length of the lens from its concave side, as the means of determining the quantity and direction of rays that are to be transmitted, flratement of The advantage of this construction over the common camera n» advantages, 0.VjScura jg such, that no one who makes the comparison, can doubt of its superiority ; but the causes of this may require some explanation. It has been already observed, that by the common lens, any oblique pencil of rays is brought to a focut at a distance less than that of the principal focus. But In the Construction above described, the focal distance of oblique penr cils is not merely as great, but is greater than that of a direct pencil. For since the effect of the first surface is to occasion divergence of parallel rays, and thereby to elongate the focus ultimately produced by the second surface, and since the de- gree of that divergence is increased by obliquity of incidence, The oblique the focal length resulting from the combined action of both pencils have a surfaces will be greater than in the centre, if the incidence on longer focus ° . •than the prin- «ie second surface be not so oblique as to increase the con- tipai focus. \>ergence. On this account, the opening E is placed so much nearer to the lens than the centre of its second surface, that oblique rays Ef, after being refracted at the first surface, are transmitted through the len3 nearly in the direction of its shorter radius ; and Tience are made to converge to a point so distant, that the image (at /) falls very nearly in the same plane with that of an object centrally placed . The aperture In the use of spectacles by long-sighted persons, the course struction re- °*" tne rays *n $9- °PP0S'te direction is so precisely similar, presents by that the same figure might serve to illustrate the advantages oTpT^oTthe6 °^ t"e periscopic construction. For the purpose of seeing the eye in the p. extended page of a book (as at AB) with least fatigue to the spectacles. e^ tkat form of lens will be most beneficial, which renders the rays received from each part of its surface parallel ; and this is effected by the exact counterpart to the preceding ar- rangement 3 for in this case the opening E represents the place of the eye receiving parallel rays from the lens in each direction, instead of transmitting them from a distance towards it. fimit of ad- There is, however, this difference between the two cases, that PERISCOMG CAMERA AND MICROSCOPE. 2J) that in the camera obscura, a much larger portion of the lens ^^ m * is required to conspire in giving a distinct image of any one object; so that the conformation best adapted for lateral ob- jects would not be consistent with distinctness at the centre ; and hence arises a limit to the application of the principle. On the common construction, the whole lens is so formed, as to give brilliancy and distinctness at the centre alone, without regard to lateral objects. In adopting such a deviation from the customary form, as I propose, in favour of a more ex- tended view, some diminution of the aperture is required in order to preserve the desired distinctness at the centre. In my endeavours to ascertain the most eligible form of meniscus Best construe for this purpose, I have assumed sixty degrees to be the field j'°" ^i ^ of view required. But when so large a field is not wanted, vi6Vy. then a lens that is less curved will be preferable ; and the propor- tion of the radii must be varied according to the angular extent intended to be included. For the purpose of estimating by what combination of radii D,1,a?r^nV>5" any required focal length may be given to a meniscus, I have which the contrived a diagram by which very much labour of computa- radii or lense* are settled. tion may be saved, as a very near result may be obtained by mere inspection. This contrivance is founded on the well known formula for the focal length of any lensF=-— gj3;;r' m being a certain multiple obtained by dividing the sine of refraction by the difference of the sines of incidence and re- fraction. Hence, in applying this formula to the meniscus, F : R : : mr : R — r. In fig. 3, lines expressive of these quan- tities are so arranged, that by assuming any point F corres- ponding to the focal length desired, and drawing a line FR through a point R indicating any supposed length of th© greater radius, the corresponding length of the other radius will be found where the line drawn intersects the middle line in the diagram. Inlaying down these lines, the length and position of AF and AR were assumed at pleasure j and they were divided into any number of equal parts. But the position and length of the middle line Ar was adapted with care to the refractive power of plate glass in the following manner, Since m = »'-,.,. .■ g= 1,08, a line BC was drawn, from the point 10 in the 30 FERISCOPIC CAMERA AND MICROSCOPE. the line AR, parallel to AF, and equal to 19,8 divisions of the primary lines j so that if r be = JO. then the line BC a= mr. The distance AC being then divided into ten equal parts, with their subdivisions, afforded the means of continuing the same scale to any desired length. Since the first line BC was laid down parallel to AF, and equal to mr, any other lines drawn through corresponding numbers 7 and 7, 8 and 8, &c. will be also parallel, and by preserving due proportion, will correctly represent mr. Hence in all positions of the line FR, the same similarity of triangles obtains, and the same proportion of F : R : : mr : R — r -, and consequently the focal length, corre- sponding to any assumed radii, is truly ascertained. For the purpose of duly proportioning the curvatures of flint glass, a second line Ay might be laid down in a mode similar to the preceding, by adapting the multiple m= == — to the different density of this glass. Periscopic With respect to the construction of a microscope on peris- cope.6 micros" copic principles, I believe the contrivance to be equally new with the former, and equally advantageous. The great desU. deratum in employing high magnifiers is sufficiency of light 3 and it is accordingly expedient to make the aperture of the little lens, as large as is consistent with distinct vision. But if the object to be viewed, is of such magnitude as to appear under an angle of several degrees on each side of the centre, the requisite distinctness cannot be given to the whole surface by a common lens, in consequence of the confusion occasioned by oblique incidence of the lateral rays, excepting by means of a very small aperture, and proportionable diminution of light. Two piano- In order to remedy this inconvenience, I conceived that the placedVace^o Perf°ratea< metal, which limits the aperture of the lens, might face with a be placed with advantage in its centre -, and accordingly I central aper- procure(j two plano-convex lenses ground to the same radius, ture in a plate r r & > between them, and applying their plane surfaces on opposite sides of the same aperture in a thin piece of metal (as is represented by a section, fig. 4), I produced the desired effect $ having virtually a double convex lens so contrived, that the passage of oblique pencils was at right angles with its surfaces, as well as the Dimension*, central pencil. With a lens so constructed, the perforation that HARDENING OF STEEL. 31 that appeared to give the most perfect distinctness was about one-fifth part of the focal length in diameter j and when such an aperture i9 well centered, the visible field is at least as much as twenty degrees in diameter. It is true^ that a portion of light is lost by doubling the number of surfaces ; but this is more than compensated by the greater aperture, which, under these circumstances, is compatible with distinct vision. Beside the foregoing instances of the adaptation of peri- pej f^op^c11 ° scopic principles, I should not omit to notice their application principles to to the camera lucida ; as there ii one variety in its form, that fUgi(J*mera was not noticed in the description which I originally gave of that instrument*. In drawing, by means of the camera lucida, distant objects are seen by rays twice reflected (d, fig. 5), at the same time and in the same direction that rays (e) are received from the paper and pencil by the naked eye. The two reflections are effected in the interior of a four-sided glass prism, at two pos- terior surfaces inclined to each other at an angle of 135 de- grees. In the construction formerly described, the two other surfaces of the prism are both plane, through which the rays ar« simply transmitted at their entrance and exit. But since an eye that is adjusted for seeing the paper and pencil, which are at a short distance, cannot see more distant objects dis- tinctly without the use of a concave glass, it may be assisted in that respect by a due degree of concavity given to either, or to both the transmitting surfaces of the prism. It is, how- ever, to the upper surface alone that this concavity is given 5 for since the eye is then situated on the side toward the centre of curvature, it receives all the benefit that is proposed from the pei iscopic principles. VI. Practical Experiments on hardening Steel. By Mr E.Lydiatt, Lecturer on metallurgy, and the mechanic Arts, &c. In a letter from the Author. • To W. Nicholson, Esq. Sir, THE desire I feel to be instrumental in promoting the cause Introduction, of science and truth, makes me regret that indispensable avo- • Nicholson's Journal, XVII, p. 1. Phil. Magaz. XXVII, p S43. cations 3l2 HARDENING OF STEEL.' cations prevent me from communicating much information t6 your valuable, journal, that would stand a chance, at least, of being useful to many of your readers. Common Te- To this circumstance alone, is to be referred the delay of my nac,ty of ™e* promised communication on the tenacity of the different metals. The time necessarily required to complete experiments on this subject, I have not yet been able to appropriate to that purpose j and I am sorry that it must consequently still stand over, subject however to a determination to fulfil my promise on the earliest opportunity. In the irean time, a few remarks on interesting mechanical subjects, may not prove unacceptable. Hardening of The present paper contains some practical experiments on warping. hardening steel; the results of which have, in a great measure, proved successful in preventing warping: an inconvenience hitherto inseparable from the operation. The u?.ual pro- The process usually practised for hardening, is to heat the ""sis the* aUd Steel Sraduaily t0 a red heat» and lhen P^nge it into cold water, work. which produces the desired effect j but it is a subject of regret with all workers of this metal, that the figure of their work, is frequently changed by the operation, to such a degree, as to render useless all previous labour, and accuracy of workman- ship. The subject The limited extent of human knowledge respecting the organ- does not re- t jzation of matter, will only allow us to speak hvpothetically quire theoreti- , . . i , "^ r , , cal disquisi- as t0 tne occult causes to which these effects are referable. tions. I shall not, therefore, on the present occasion, cloud the inves- tigation of familiar operations, with the subtilties of philo-- sophical disquisition j but proceed to the more useful part of my task. Heated steel Pyrometrical experiments prove that steel, when heated so as contracts, by to carry expansion to its utmost limit, if suffered to cool gra- first 'dni'ien-1* duaHy and °^its own accorcl> ViM return precisely to its original sions. figure and dimensions. The detrimental effects produced by the operation of hardening, mus/ therefore be occasioned, by some derangement of the particles, on the sudden expulsion of caloric. Keeping this idea in my mind, I thought, perhaps, if a piece of steel were repeatedly heated to different degrees below the hardening point, and as frequently quenched in cold water^, this process might operate ajteratively -9 and induce a different arrange- HARDENING OF STEEL. 33 arrangement, more favourable to the instantaueous expulsion, of a larger proportion of caloric. To prove this I made experiments with three cylindrical pieces Experiments. of steel, six inches long, and half an inch diameter, accurately steei'^|° turned : the first of which I hardened in the usual way, and on heated and examination, found it had deviated from a straight line '05 In. sud^en,y ' a cooled, warp- The second piece, I heated just sufficient to occasion a fainted: another hissing noise when dipped in the water : then a second time a Plcce repeated- ,. , , , f , . . . . 'y heated and little hotter, and quenched it as belore : repeating this operation cooled at suc- four or five times, increasing the degree of heat each time ; CC831ve!y ^in- keeping, however, below the hardening point till the last, where did not. it was heated to a blood red and hardened ; and to my surprise remained as perfectly straight and unaltered, as before the operation. The third piece I treated in the same way, and experienced A third, piece nearly similar results ; and since the time of making these ex- HkethTse- periments, I have had various opportunities of practising the cond, and with process j and in every instance have found it effectual beyond *hesame re~ my expectation. For smaller articles, to which the above method is not appli- Small articles cable, I have found that by using water whose temperature is were hardened raised to 200°, the steel is not only perfectly hardened, but preserved from the disagreeable consequence, which the use of water at its common temperature, in general produces. In the hope that the results of these experiments may prove- useful, I offer them for publicity through the medium of your valuable journal $ from which I readily acknowledge to have derived many hints myself, which have proved important in practice as well as theory. E. LYDIATT. London, Dec. 5 th, 1812. Annotation. W. N. As the hardening of steel is higher, and the contraction byAnotherme- cooling, less, the greater the heat of the ignition. I many years fhots mouth, as some naturalists assert, but from a small opening at the upper part of the belly, which communicates by a narrow duct, to a bag or bladder, situated near the coecum, in by which the which this liquor is formed. The cuttle fish is said to avail fi.hissaidto itself of this property when chased by other fishes, and thus, mie*. ' * by rendering the water turbid anil opake, it is enabled to elude their SEPIA, OR CUTTLE FISH. 35 their search, — Now it is to an examination of this peculiar liquor or sepia, supposed by Rondelet to be the ^bile of the cuttle fish, that I beg leave to call the attention of the reader ; premising, however, that the sepia which I used was taken immediately from the fish, as no dependence can be placed on that which is exposed for sale, which is probably mixed with gum arabic, or some other foreign ingredient. The sepia, when fresh, is a black glary liquid of a viscid Properties of consistence, a peculiar fishy smell and very little taste. p a" Being subjected to experiment it afforded the following results. l.'It mixed readily with distilled water in any proportion, it mixes with and shewed little or no disposition to subside after standing water, many hours : when the mixture was submitted to filtration, a considerable quantity of sepia was left behind, and what passed the filter was a thin black liquid, being a saturated solution of sepia in water. 2. Being poured into alcohol it coagulated immediately. Coagulates 3. The same effect was produced by mixing it with ether. and with ether 4. Alcalies appeared to facilitate the solution of sepia in Alcalies assist aqueous menstruum ; Potash changing its colour to a brown, its solution, but ammonia not affecting it, after, however, it had undergone spontaneous evaporation to dryness, it became sparingly soluble in solutions of pure fixed and volatile alcali, but its colour re- mained unaltered by either. 5. When some of the saturated solution of sepia was boiled r* coagulates the sepia coagulated. b? boi,inS if 1 a saturated, 6. But when a very weak solution of it was boiled, coagula- but not if tion did not take place. weak. 7. The sepia which was precipitated from its solution by The last coagu- boiling, was soluble in nitric acid when assisted by heat. in'hot STtu 8. After separating by filtration the sepia coagulated by The clear boiling, fiom the water in which it had been dissolved, a pre- "'quor of No. ... ........ /- 1, 5, was precip. cipitate was obtameo by dropping in tinct. of galls. hv galls 9. A light brown precipitate was also obtained by adding a and also by ox. solution of oxymuriate of mercury to another quantity of. the water. 10. The sulphuric, nitric, and muriatic acid precipitated the Sol of sepia ig sepia from- its solution in water.- The sulphuric and muriatic PeciP- by acids, D % did 30 SEPIA, OR CUTTLE FISH. did not affect its colour, but the nitric after standing a day or two changed it to a brown. but not by ox. li. Oxymuriatic acid did not occasion a precipitate with the solution of sepia j and mixed in the proportion of one part of the former to three of the latter, the colour was not affected ; but when mixed in equal parts, it was changed to a brown. Dried s. is ]2. Sepia, after having been dryed by spontaneous evapora- a * lion, was insoluble in oxymuriatic acid. Ox.mur. of 13. A solution of oxymuriate of mercury being added to a dD^coDUJuriv solution of sepia, occasioned a copious precipitate. as does nitrate 14. Nitrate of silver precipitated sepia from its solution in ot suver, water, but did not injure its colour. and also sulph. 1.5. Some solution of sulphate of iron, being dropped into a ot iron. solution of sepia, the sepia was precipitated, but its colour was not affected. Deduction. From the above experiments, particularly from 2, 3, 5, (5, 7* 11, and 13, we may reasonably infer, that the sepia is composed for the most part of albumen. Example 8 and 9 indicate the presence of gelatine. Sepia stands As tne oxy muriatic and nitric acids have so little effect on the colour. colour of sepia, we may confidently conclude that it possesses the valuable property of standing well. This conclusion is also strengthened, and in a great measure confirmed, by the information of Dr. Leigh, from whom we learn that sepia has been sometimes used as writing ink, and that in a piece of writing of ten years standing, which he had seen, the colour of the sepia was still retained. Indian ink It has been conjectured by some writers,* that Indian ink is tdo be™™™.6** nothing else than the sePia of the cuttle fish- A ve,7 intelligent gentleman, with whom I corresponded on the subject, and who was of a contrary opinion, writes me as follows : ** I have great reason to believe that not a particle of sepia enters into Sepia is far the composition of Indian ink. The colour is very different j superior. ancj gep-ia jg as SUperior t0 Indian ink with respect to the ease of working * " Sepia piscis est qui habet succum nigerrimum instar atramenti quern chinenses cum brodiooriza vel alterius leguminis inspicsant et formant, et in universuni orbem transmittunt,sub nomine atramenti Chinensis." — Pauli Hermani cynosura, t. 1. p. 17, pars II. Vide etiam Elemens de Chirnie, par M. Chaptal, torn. iii. p. 357;Moutpellier edit. 17D0. TENDRILS OF PLANTS. 3J working, as Indian ink is to lamp black, I do not mean to say that it make* a clearer shadow ; but Indian ink dries much quicker than sepia — an important consideration where a very large pale shadow is wanted. If too, a mistake be made with sepia, it may be washed almost clean off, whereas part of the Indian ink, if once dry, will adhere to the paper and resist every effort to remove it, without absolutely rubbing up the surface. I could point out other differences between Indian ink and sepia." To such artists as, by residing near the coast, have an op- Sepia drierf portunity of procuring the cuttle fish from fishermen, I fxpo"ure to^ would recommend the following simple means of preserving the air the sepia.— After carefully taking the bag out of the fish, ]£*yJ^ J^J* having previously secured the duct by a ligature to prevent the sepia from running out, empty the contents of it into a saucer - or gallipot, and after spreading it round the sides of the vessel, surfer it to dry gradually by exposure to the air. The reason for only coating the sides of the vessel is in order that it may dry before putrefaction commences. In this dry state it will keep for any length of time, and will always be fit for use, by being rubbed up with a little water, GROVER KEMP. Brighton, 11 Mo. 26, 1812. VIII. On the Motions of the Tendrils of Plants. By Thomas An- drew Knight, Esq. F. R. S. From the Philosophical Transactions for 1812. THE motions of the tendrils of plants, and the efforts they Thetendrlls of apparently make to approach and attach themselves to con- P{an*shave tiguous objects, have been supposed by many naturalists to to movePfrom originate in some degrees of sensation and perception : and sensation and though other naturalists have rejected this hypothesis, few, or percePtu no experiments have been made by them to ascertain with what propriety the various motions of tendrils, of different kinds, can be attributed to peculiarity of organization, and the operation of external causes. I was consequently induced, during the last summer, to employ a considerable portion of time 38 TENDRILS OF TLANTS. time to watch the motions of the tendrils of different species of plants ; and I have now the pleasure to address to you an account of the observations I was enabled to make. Experiments The plants selected were the Virginia creeper (the ampe- with the Vir-j0pSjs qlimquefolia of Michaux,) the ivy, and the common ginia creeper, » the ivy, the vine and pea. common vine, a plant of the ampelopsis, which grew in a garden pot, was The V. creep- removed to a forcing house in the end of May, and a single er insulated, shoot from it was made to grow perpendicularly upwards, by dril towards a" DeniS supported in that position by a very slender bar of wood, wall eight feet to which it was bound. The plant was placed in the middle of the house, and was fully exposed to the sun j and every object around it was removed far beyond the reach of its ten- drils. Thus circumstanced, its tendrils, as soon as they were nearly full grown, all pointed towards the north, or back wall, which was distant about eight feet : but not meeting with any thing in that direction to which they could attach themselves, they declined gradually towards the .ground, and ultimately attached themselves to the stem beneath, and the slender bar of wood. Another plant A P^ant °^ tne same sPecies M as placed at the east end of differently situ- the house, near the glass, and was, in some measure, screened TendriUo the'tS ^rom ^ie PerPen(Jicular ngnt 5 when its tendrils pointed to- part most wards the" west, or centre of the house, as those under the sia ' preceding circumstances had pointed towards the north and back wall. This plant was removed to the west end of the house, and exposed to the evening sun, being skreened, as in *► the preceding case, from the perpendicular light ; and its ten- drils, within a few hours, changed their direction, and again pointed to the centre of the house, which was partially covered and when fully w,tn v'ines- This plant was then removed to the centre of the illuminated, house, and fully exposed to the perpendicular light, and to turne to an the sun ; and a piece of dark-coloured paper was placed upon ' one side of it just within the reach of its tendrils ; and to this substance they soon appeared to be strongly attracted The paper was then placed upon the opposite side, under similar circumstances, and there it was soon followed by the tendrils, bat not to a It was then removed, and a piece of plate glass was substi- transparent tuted ; bnt to this substance the tendrils did not indicate any ' disposition to approach. The position of the glass was then changed, TENDRILS OF PLANTS. 39 changed, and care was taken to adjust its surface to the varying position of the sun, so that the light reflected might continue and receded to strike the tendrils ; which then receded from the glass, and ingone# appeared to be strongly repulsed by it. The tendrils of the ampelopsis very closely resemble those The claws of of the vine, in their internal organization, and in originating gj^jj'ariv a"* from the alburnous substance of the plant ; and in being, under fected.bot at certain circumstances, convertible into fruit stalks. The claws, ledS dl$tances- or claspers of the ivy, to experiments upon which I shall now proceed, appear to be cortical protrusions only ; but to be capable, I have reason to believe, of becoming perfect roots, under favourable circumstances. Experiments, in every re- spect very nearly similar to the preceding, were made upon this plant ; but I found it necessary to place the different sub- stances, to which I proposed that the claws should attempt to attach themselves, almost in contact with the stems of the plants. I observed, that the claws of this plant evaded the light, just as the tendrils of the ampelopsis had done ; and that they sprang only from such parts of the stems as were fully or partially shaded. A seedling plant of the peach tree, and one of the ampe- The stems of lopsis and ivy, were placed nearly in the centie of the house, l"^v cr.eel>er» and under similar circumstances j except that supports, formed inclined to-' of very slender bars of wood, about four inches high, were wards a tree* applied to the ampelopsis and ivy. The .peach tree continued to grow nearly perpendicularly, with a slight inclination to- wards the front and south side of the house, whilst the stems of the ampelopsis and ivy, as soon as they exceeded the height of their supports, inclined many points from the perpendicular line, in the opposite direction. It appears, therefore, that not only the tendrils and claws of Not only the these creeping dependent plants but that their stems also, are tfndr,k»but j / i- I 1 • . . - the stems of made to recede from light, and to press against the opaque plants incline bodies, which nature intended to support and protect them. to their »"P- M. Decandole, I believe, first observed, that the succulent This effect is shoots of trees and herbaceous plants, which do not depend opposite to the upon others for support, are bent towards the point from succulent" which they receive light, by the contraction of the cellular plant?, substance of their bark, upon that side, and I believe his opi- nion to be perfectly well founded. The operation of light upon 40 TENDRILS OF PLANTS. upon the tendrils and stems of the ampelopsis and ivy, appears to produce diametrically opposite effects, and to occasion an extension of the cellular bark, wherever that is exposed to its influence ; and this circumstance affords, I think, a satisfactory explanation why these plants appear to seek and approach contiguous opaque objects, just as they would do, if they were conscious of their own feebleness, and of power in the objects to which they approach, to afford them support and protection. The vine con- The tendril of the vine, as I have already stated, is inter^ explanation*.™6 na^ Mmilar to that of the ampelopsis, though its external form, and mode of attaching itself, by twining round any slender body, are very different. Some young plants of this species, which had been raised in pots in the preceding year, and had been headed down to a single bud, were placed in a forcing-house, with the plants I have already mentioned j and the shoots from these were bound to slender bars of wood, and trained perpendicularly upwards. Their tendrils, like those of the ampelopsis, when first emitted, pointed upwards j but they gradually formed an increasing angle with the stems, and ultimately pointed perpendicularly downwards 3 no object having presented itself to which they could attach themselves. Other plants of Other plants of the vine, under similar circumstances, were the viae. trained horizontally ; when their tendrils gradually descended beneath their stems, with which they ultimately stood very nearly at right angles. A third set of plants were trained almost perpendicularly downwards j but with an inclination of a few degrees towards the north j and the tendrils of these permanently retained very nearly their first position, relatively to their stems ; whence it appears, that these organs, like the tendrils of the ampelop- sis, and the claws of the ivy, are to a great extent under the control of light. Thevinedif- A. few other plants of the same species were trained in each fers from the of the preceding methods j but proper objects were placed, in creeper. different situations, near them, with which their tendrils might come into contact j and I. was by these means afforded an op- portunity of observing, with accuracy, the difference between the motions of these and those of the ampelopsis, under similar circumstances. The latter almost immediately receded from light, by whatever means that was made to operate upon them j and TENDRILS OF PLANTS: 41 and they did not subsequently shew any disposition to approach the points from which they once receded. The tendrils of the vine, on the contrary, varied their positions in every period of the day, and after returned again during the night, to the situations they had occupied in the preceding morning j and they did not so immediately, or so regularly, bend towards the shade of contiguous objects. But as the tendrils of this plant, like those of the ampelopsis, spring alternately from each side of the stem, and as one point only in three is with- out a tendril, and as each tendril separates into two divisions, they do not often fail to come into contact with any object within their reach ; and the effects of contact upon the tendril are almost immediately visible. It is made to bend towaids the body it touches, and if that body be slender, to attach itself firmly, by twining round it, in obedience to causes which I shall endeavour to point out. The tendril of the vine, in its internal organization, is ap- Explanation of parently similar to the young succulent shoot, and leaf-stalk, J^ ^^rTdrilT <5 of the same plant j and it is as abundantly provided with ves- the vine as- sels or passages for the sap j and I have proved, that it Is SSTaiSf cur- alike capable of feeding a succulent shoot, or a leaf, when vature. grafted upon it. It appears, therefore, I conceive, not impro- bable, that a considerable quantity of the moving fluid of the plant passes through its tendrils j and that there is a close con- nection between its vascular structure and its motions. I have proved, in the Philosophical Transactions of 180(5, that centrifugal force, by operating upon the elongating plu- mules of germinating seeds, occasions an increased growth and extension upon the external sides of the young stems, and that gravitation produces correspondent effects j probably by occasioning the presence of a larger portion of the fluid orga- nizable matter of the plant upon the one side, than upon the other. The external pressure of any body upon one side of a tendril, will probably drive this fluid from one side of the ten- dril, which will consequently contract to the opposite side, which will expand $ and the tendril will thence be compelled to bend round a slender bar of wood or metal, just as the stems of germinating seeds are made to bend upwards, and to raise the cotyledons out of the ground j and in support of this conclusion I shall observe, that the sides of the tendrils where in 42 MURIATIC AND OXYMURIATIC ACIDS. in contact with the substance they embraced, were compressed and flattened. The tendrils The actions of the tendrils of the pea were so perfectly affecteTas "" similar to tllose °f tne vine» wnen lne>r came into contact whh those of the any body, that I need not trouble you with the observations I *me* made upon that plant. An increased extension of the cellular substance of the bark upon one side of the tendrils, and a cor- respondent contraction upon the opposite side, occasioned by the operation of light, or the partial pressure of a body in contact, appeared in every case which has come under my observation, the obvious cause of the motions of tendrils ; and therefore, in conformity with the conclusions I drew in my last memoir, respecting the growth of roots, I shall venture to infer, that they are the result of pure necessity only, uninfluenced by any degrees of sensation, or intellectual powers. T. A. KNIGHT. Doivnton, April 2J ', 1812. IX. Introductory remarks. Reference to the contro- versy between Mr. Murray and Mr. John Davy. Additional Experiments on the Muriatic and Oxy muriatic Acids. By William Henry, M. D. F. R. S. V. P. of the Lit. and Phil, Society, and Physician to the Infirmary at Manchester. From the Philosophical Transactions, 1812. THE experiments, which form the subject of the following pages, are intended as supplementary to a more extensive series, which the Royal Society did me the honour to insert in their Transactions for the year 1800*. Of the general accu- racy of those experiments, I have since had no reason to doubt ; and their results, indeed, are coincident with those of subsequent writers of the highest authority in chemistry. My attention has been again drawn to the subject by the impor- tant controversy which has lately been carried on between Mr. Murray and Mr John Davy, respecting the nature of mu- riatic and oxymuriatic acidsf ; and I have been induced, by some hints which the discussion has suggested, not only to * Page 188. f Nicholson's Journal, XXVIII, and XXIX. repeat MURIATIC AND OXYMURIATIC ACID5. 43 repeat the principal experiments described in my memoir, but to institute others, with the advantage of a more perfect appa- ratus than I then possessed, and of greater experience in the management of these delicate processes. This repetition of my former labours has discovered to me Uncertainty of an instance in which I have failed in drawing the proper con- an expenment b ' l . of the quantity elusion from facts. In two comparative experiments on the of hydrng. electrization of equal quantities of muriatic acid gas, the one evolved from , i , • • i' iii • mur. ac. gas ot which was dried by muriate of lime, and the other was in drje(j and not its natural state, I found a difference of not more than one per dried. cent, in the hydrogen evolved, relatively to the original bulk of the gas*. Yet, notwithstanding these results, I have ex- pressed myself iricfined to believe, that some water is abstracted by that deliquescent salt ; and this belief was confirmed, seve- ral years afterwards, by the event of an experiment in which muriatic acid gas, dried by muriate of lime, gave only Jj. hs bulk of hydrogenf, a proportion much below the usual ave- rage. The question, however, was too interesting to be left in any degree of uncertainty j and I have, therefore, made several fresh experiments with a view to its decision, in the course of these I have found, that though differences in the results are . produced by causes apparently trivial, some of which I shall afterwards point out, yet that under equal The quantjtv circumstances, precisely the same relative proportion of hy- is the same, drogen gas is obtained from muriatic acid gas, whether ex- w ieP^lte. & => ° muriatic acid posed or not to muriate of lime ; and that its greatest amount gas be exposed does not exceed Jr or V-tj the original volume of the acid gas. °.r not *° ' 111U" 1 b ' 4 ° ° nate of lime. In the paper last quoted* Itiave also described an experi- • i , -, , , i , , , • • • Muriate of ment, in which sensible heat was evolved by bringing muriate ijme does not of lime into contact with muriatic acid gas ; a fact which, if unless humid, established, would go far to. prove the existence of water in w;tn muriatic that gas. But on repeating the experiment with muriate of acid gas. lime recently cooled from fusion, and over mercury carefully deprived of all moisture by boiling, I was not able to discover any increase of temperature, though a very sensible air ther- mometer was inclosed in the vessel containing the gas. The evolution of heat takes place, only when 4he muriate of lime * Page 191. f Phil. Trans. 1809, page 433. } Page 433, note. hat 44 MURIATIC AND OXYMURIATIC ACIDS* has attracted moisture, either from the atmosphere or the mercury, and is then owing to a condensation of a part of the gas. Muriatic acid Essentially, the changes produced by electrifying muriatic Srr when***" ac',J over mercury are tnose which I have stated ; viz. a con- tler'tiified, traction of the volume of the gas, the formation of muriate of w^rfmulv- mercur.v (calomel,) and the evolution of hydrogen. Recent cirogen ; hut experiments, also, have confirmed the accuracy of the obser- 10 a certain ex- vation*, that when a certain effect has been produced by elec- tee only. .. . . , .,, .. , - . , tricity, nothing is gained by continuing the process j for neither is more hydrogen evolved, nor can the contraction of bulk be carried any farther. Muriatic acrd I have lately applied, to experiments on muriatic acid, an jjas-, electrified ...» , ■> - • t. . ' » in a vessel, apparatus which 1 used advantageously for the analysis of without the ammoniaf . It consists of a spherical glass vessel, into which T2r£!3CnCC of any other are hermetically sealed two small tubes containing platina *»"d» wires, the points of which approach within the striking dis- tance. To the globular part is attached a neck, which may be closed, as occasion requires, either by a glass stopper, or by a metal cap and stop-cock. Into a vessel of this kind I intro- duced A\ cubic inches of muriatic acid gas, and passed through whin™ ]t 300° discharges from a Leyden jar ; at the close of the process, no traces of moisture could be perceived on th& inner surface of the vessel ; nor could I discover, on opening hut when the the stopper, that any change of bulk had taken place. After sas was ah- absorbing the unchanged muriatic acid gas by a small quan- stracted, the tity of water, a volume of gas remained, in which there were small residue , * - , . was oxymuria- Present 10° measures (each equal to one gram of mercury) tic acid gas of oxymuriatic acid gas, and 140 measures of hydrogen. Two i) rogen. cauges migh^ perhaps, contribute to diminish, in some degree, the proportion of the former. Jt was difficult to exclude from the apparatus, on admitting the muriatic acid gas into it, two or three very minute globules of mercury, which became tar- nished during the experiment, exactly as they would have been by oxymuriatic acid ; and a small portion of the latter gas waa probably also taken up by the water employed to absorb the muriatic acid. Repetition on With the intention of giving greater effect to the electricity, * Phil. Trans. 1800. p. 192. i Ibid, 1809. I re* MURIATIC AND OXYMURIATIC ACIDS. 45 I repeated the experiment in a vessel capable of containing a smaller «•*»*'• , ./-.,... r ..with the»auie not more than 1400 grains of quicksilver, (about '41 of a cubic resu|t. inch,) the neck of which being only one-fifth of an inch in dia- meter, was better calculated to show any minute change in the volume of the gas. On removing the stopper, however, no change of volume was apparent. The hydrogen erolved, in- stead of being more than in the former experiment, equalled in bulk only 20 grains of mercury. The production of oxy- nmriatic acid was sufficiently evinced by its effect in tarnishing some very small globules of quicksilver, which adhered to the inside of the vessel ; but- the minuteness of the quantity frus- trated an attempt to measure it. From subsequent expert* ments on similar quantities of gas, confined in the same appa- ratus, it appeared, that the electrization in this last instance, had been continued much longer than was necessary ; and that an equal effect was produced by one-eighth the number of elec- trical discharges. In this way of making the experiment, the greatest propor- The hydrogea tion of hydrogen gas obtainable from muriatic acid, amounted evolved when i iiiii-i.. , ., mercury is not only to about .^th, while, b/ electrization over quicksilver, present, i« tV, or t!t was generally evolved. It was evident, then, that 1*70th ; blU d 1 ■ ' * D J ' ' present, the mercury had considerable influence over the results ; and i-l5th,or I found, by experiments with tubes of different diameters, "e'ir!y five „. ■ times as much, that the larger the surface of the mercury exposed to the gas, the more rapid and complete was the change. Its action was greatly accelerated, also, by causing the electric discharge to strike from the conducting wire, sealed into the tube, to the mercury, which was probably thus raised into vapour; for in some instances, the whole of the inner surface of the glass was coated with sublimed calomel. The only way in which the mercury appeared to me likely The mercury to be efficient in this case, was by removing the oxymuriatic f PPears to a'" agency, and will reproduce muriatic acid. Thii point appears, became* abua. from daat 1 46 MURIATIC AND OXYMURIATIC ACIDS. from my experiments, to be attained, when the hydrogen and oxymuriatic acid, taken together, have the proportion to the viz. both gases muriatic acid, of about 1 to 35. The amount of the change, as {h:e™'nal'c therefore, which is capable of being effected on muriatic acid gas, electrified without the contact of mercury, is limited by the reaction of the evolved hydrogen and oxy muriatic acid gasses on each other, whenever they compose a certain pro- portion of the mixture. This proportion being attained, we only, by continuing the electrization, work in a circle. Muriatic acid It may now be inquired, what is the limitation to the action •ver mercury, 0f electricity on muriatic acid gas, which is confined over mer- cury ? In this case it was suggested to me by Mr. Dalton, who favoured me with his presence at most of the experi- ments, that the evolved hydrogen might possibly in some way prevent the effect from being carried beyond a certain amount. Availing myself of this hint, I mixed thirty measures of hydrogen gas with 400 of muriatic acid gas in its ordinary with about state, and passed 900 discharges through the mixture. It soon 1;\3tl!lts buIk became evident that the addition of the hydrogen bad pro- of hydrogen, . ' - ■ i3 not changed duced an important difference in the results of the experi- by electriza- ments -, for the surface of the mercury, over which the gas rested, was untarnished after some hundred explosions, and was scarcely changed at the close of the process. When the residuary gas, the volume of which remained unaltered, was analyzed, it was found to contain the same quantity of muria- tic gas, as at the outset, and neither more nor less hydrogen, because the To explain the event of this modification of the experiment, wtternfinTsd on the old theory, we may suppose, that, by the action of elec- hydrogen to tricity, a particle of water is decomposed, and that the atom of recompose it : 0XVg-eil) forcibly repelled from that of hydrogen with which it was associated, finds another atom of hydrogen uninfluenced by the electric fluid, and within the sphere of its attraction. With this it unites, and recomposes water. On the theory of or themuriatic Sir H. Davy, the same series of decompositions and recombi- posed and^re™ nat,ons may De assumed to take place between the oxymuriatic composed. acid and hydrogen*. It * I am aware, that there is an apparent inconsistency in supposing changes of precisely an opposite kind to be effected by the same means. But instances are not wanting, in which the very same elements are krought into combination by electric discharges, and are again disunited by MURIATIC AND OXYMURIATIC ACIDS. 47 It still, however, remains to be determined, what is theQu: Whence source of the hydrogen gas, which, in a limited proportion, umitedhydrog. is always evolved by the electrization of muriatic acid ? Does evolved by it result from the decomposition of water, existing as an ele- J^om^vvater ment of the gas ; or from the disunion of the oxymuriatic acid as an element and hydrogen, which, according to Sir H. Davy's view, com- J? theffam' the pose muriatic acid ? The limitation to its amount, which, it disunion of formerly appeared to me* ceuld only be accounted for by the hydrog. from. J rt .ii oxymur. acid complete destruction of the water contained in the gas, may as elements of now be equally well explained, on the principle which I have mur« acid? just pointed out. The fact, also, that no appreciable change of bulk is produced by the electrization of the muriatic acid, when the presence of mercury is excluded, is perhaps favour- „ , , , . i^i, Perhaps the able to the new theory. For since equal measures of hydro- ]atter; because gen and oxymuriatic acids afford muriatic acid without any tue volume* condensation of volume, no alteration of bulk should result ^ » from the disunion of those elements ; and the products should be equal measures of the same gases. The proportions, which I obtained (100 to 140) did not, it must be acknowledged, exactly correspond with the theory j but the difference was not greater, than might naturally be expected from the cir- cumstances of the experiment. That equal measures of hy- drogen and oxymuriatic acid are really evolved, appears to me to be proved by the agreement, which I have in several experiments remarked, between the hydrogen gas obtained, and the contraction of volume in muriatic acid electrified over mercury. Now the latter effect of the process can be explained on no other principle than the absorption of oxymuriatic acid by the quicksilver. When muriatic acid and oxygen gases are electrified toge- by the same agency. As examples, it may be sufficient at present to state, that nitrous acid and nitrous gas are generated by the action of the electric spark on mixtures of oxygen and nitrogen gases; and that, by the same power, they are again resolved into their elements. If this were the proper place, it might* I think, be rendered probable by several arguments, that electricity, when thus applied, acts rather by mechanical collision, than by inducing a change in the electrical states of the elements of bodies. * Phil. Trans. 1800, p. 200. ther 48 MURIATIC AND OXYMURIATIC ACIDS. ther over" mercury, a gradual diminution ensues in their bulk,* and the mercury becomes tarnished, precisely as by the contact of oxymuriatic acid. I have lately examined the agency of Muriatic acid tnjs process on a considerable quantity of the two gases gases, electrifi- confined in a vessel, into which they were admitted after ex- «d alone, hausting it by the air-pump. The phenomena, which in this afford water Jr ,. , ■ . .... . and oxymuri- way of making the experiment are extremely decisive and *tic acid gas. interesting, are the production of water and of oxymuriatic acid. The former, combining with a portion of the uudecom* posed muriatic acid, is deposited in drops upon the inner sur- face of the vessel, in the state of liquid muriatic acid. When the stop-cock, which confines the gases, is opened under mer- cury, a quantity of that metal rushes in, and has its surface instantly tarnished. Besides this test of the production of oxy- muriatic acid, its presence is rendered unequivocal (after ab- sorbing the undecomposed muriatic acid by a few drops of water), both by its smell, and by its effect in discharging the colour of litmus paperf. These result* These results, it will be found, may be reconciled with agree with J either theory, either theory. According to the one which has been com- The exigen monly received, the oxygen unites with the real acid of mu- ■nay unite . . J , . ;e. • , , with the muri- r|atic gas, which becoming oxymuriatic acid, deposits water. atic acid and On Sir H. Davy's view, the oxygen unites with the hydrogen Water be dnw- r . .... , ,., . . . rited — or the °* tne muriatic acid, and composes water, while the oxymuriatic oxigen may acid is merely aneduct. I am not aware of any refinement of hydrogen as me Pr°cess, by which the value of these two explanations can one of the be compared. Something, however, would be gained by a pie- mur" add and cise determination °f tne proportions, in which the two gases form water, saturate each other. For since, on Sir H. Davy's theory, mu- ™" ih(.\ .oxy" riatic acid contains half its volume of hydrogen gas, two mea- mur. acid is / s & ' disengaged as sures of which are known to be saturated by one of oxygen, the other prin- ciple. v * Phil. Trans. 1800, p. 193. f Those who wish to repeat this experiment need not be deterred by the apprehension of the labour attending it ; for 3 or 400 discharges! from a Leyden jar of moderate size, are sufficient to occasion a distinct precipitation of moisture. When a mixture of oxygen and muriatic acid gases is even suffered to stand over mercury, a gradual contraction of volume takes place; the muriatic acid, if in proper proportion, entirely disappears ; and calomel is deposited upon the surface of the glass vessel ; but, in this case, there is no visible production of moisture. ON PUTREFACTION. 49 it follows that muriatic acid gas should be changed into oxy- It may be of muriatic by one-fourth of its bulk of oxygen. According to v*lue to Gay Lussac andTHENARD*, three measures of muriatic acid ascertain the should condense one of oxygen (or only one-third their bulk), proportions of and should form two measures of oxymuriaic acid. Hitherto, mur. acjd gai I have not been able to satisfy myself respecting the true pro- which form portions of oxygen and muriatic acid gases, that are capable but^hishas * of being united by electricity j for-though I have made several n°t yet been experiments with this view, they have not agreed in yielding e ecte * similar results. The condensation of a part of the undecom- posed acid by the water, which is formed during the process, will, probably, indeed, always be an impediment to our learning these proportions exactly. The fact is chiefly of value, as it affords an example of the production of oxymuriatic acid under the simplest possible circumstances 5 and as it shews unequivo- cally that, under such circumstances, the visible appearance of moisture is a part of the phenomena. Manchester, Jan. 6, 1812. XI. Experiments on Putrefaction. By John Manners, M. D. of Philadelphia. In a letter from the Author. To Mr. Nicholson. SIR, FROM reading a paper upon the vinous and putrefactive Whether ory< fermentation bv Gay Liusac, in a late number of your g.en eqm* J J J site to putre- " Philosophical Journal," in which the author, according to the faction, general opinion of chemical philosophers, contended that the access of atmospheric air or oxygen gas, was a sine qua non of the process, I was induced to institute the following experi- ments on putrefaction, by which I have proved (as 1 conceive) beyond the possibility of exoeptioo, that oxygen is not only unessential to the putrefactive fermentation, but has, when in actual contact with the putrefying substance, no influence on that process. * Memoiread'Arcueil,!!. 217. Vol. XXXIV.— No. 15$. E I secured 50 ON PUTREFACTION. The water contained no oxygen. Remarks on eudiometry. Muscular flesh 1 secured some fresh muscular flesh . (a portion of lamb) in vva* included the bottom of a glass jar, and inverted it over distilled water, in air above ° J ' distilled water, observing that the water within the jar was precisely on a level with that which was external ; that any absorption of either of the components of the intercluded atmospheric air, might be noted by a corresponding absorption of water within the jar. Fahrenheit's thermometer stood at 70°. At which tempera- ture it was kept during the experiment. That the distilled water was perfectly free from any oxygen gas, I proved by Mr. Dusseu's method : viz. I tinged a portion of the same water with litmus, and passed nitrous gas through it, which Dr. Priestley proved would combine with the oxygen, and be converted into nitric avid, which would change the litmus red. Dr. Thompsou says, however, that this is not a critical test, and that the litmus will not be charged unless there be an unusual quantity of oxygen gas present. Upon the discovery of this property of nitrous gas, by Dr. Priestley, he founded the first eudiometer, which has been since mproved by Falconer, Fontana, Cavendish, Ladriani, Magellan, Baron Von Humboldt, Engenhausz, Dalton, and Gay Lussac, and contributed so much to extend the bounds of philosophical knowledge. Before this important era, the only eudiometer in the hands of the philosophers, was a sparrow, a mouse, or a taper. Since, however, others have been devised -3 as the sulphuret of iron by Scheele, the liquid hydro-sulphuret of potash by De Marti, the rapid combustion of phosphorus by Humboldt and Seguin, the slow combustion of phosphorus by Berthollet, the green sulphate and muriate of iron impregnated with nitrous gas by Davy, and the detonation of hydrogen gas by Volta. The jar remained three days, during which time the flesh rhinwTiVthe nac* undergone the putrefactive process, as was evinced by the "ncludedair offensive odour emitted. But at no time could I observe any absorption of water within the jar : except where there was a corresponding reduction of atmospheric temperature, and in consequence a condensation of the intercluded air. But Dr. Priestley, in a similar experiment, found a small augmentation of • air within the jar j as I have in subsequent experiments. The confined air was analysed with the eudiometer of Humboldt, The putrefac f icu made no Cti PUTREFACTION, 51 Humboldt, but not found to differ from atmospheric air in the proportion i f its oxygen and nitrogen. The stale of the barometer, however, Was not attended to in this experiment, which renders it liable to exception. Neither did Dr. Priestley attend to the state of the barometer in his experiments, or if he did he omitted to*mention it. I repeated this experiment over mercury. The thermometer Repetition of as before stood at 70, and the barometer at 20- 1 inches. The rhe "Pen' ' ^ ment over experiment was continued three days, when the putrefactive mercury ; with fermentation had taken place, as was evinced by the odour n0 absorption, emitted: but there was at no time any absorption of mercury within the jar. Upon examining the included air with the eudiometer it was not found to ditfer from atmospheric air. But to magnify and render more conspicuous any absorption, The same re- in consequence of a diminution of the included atmospheric ^ different1 air, by the combination of its oxygen with the animal matter, I mercurial ap- invented an instrument which I shall now describe. paratus, I took a cylindrical bottle perfectly transparent, and put half a pound of muscular flesh (a portion of the diaphram of a bullock) in the bottom of it and secured it there. The flesh was taken while warm, and cooled under mercury to prevent the access of air. To the bottle was adapted a cork which was per- forated, and a bent tube passed through the perforation, the other end of which was hermetically sealed. Some mercury was then put into the bottle — the bottle corked and made perfectly air-tight by luting and sealing — the bottle was now inverted. The mercury filled about two inches of the neck of the bottle, and was made to pass up the glass tube by heating it, and expanding the air, and thus expelling a portion of it to > a proper distance. In this situation the bottle was put to rest in a fixed position. A thermometer was included within the bottle in order to note the temperature. The bottle and curved tube in some measure represented Mr. Leslie's Differential thermometer. The barometrical influence was perfectly excluded. And as variations in the temperature equally affected both the air included in the tube, and that in the bottle, it is evident that thermometrical influence could not affect the experiment. To the tube was adapted a graduated scale, which would mark any rise or fall of mercury in the tube. E 2 Now 52 ON PUTREFACTION. calculatedto Now it is clear that the smallest diminution of air in the shewminute bottle would be marked by a corresponding fall of the mercury variations. .,.,.. . . , »• in the tube, the calibre ot which was not more than one line. Or, on the contrary, any evolution of gas would raise the mercury in the tube. No absorption The apparatus remained three days without any change of took place. mercury in the tube. On the fourth day the mercury began to rise, and continued to rise until the experiment was suspended, which proves that there was no absorption of oxygen gas by the putrefying substance. The thermometer included in the bottle stood at 60, during the experiment. This apparatus is easily constructed and may be used for many similar purposes as a gasometer. Putrefaction As from all these experiments it appeared that no oxygen effected gas was absorbed by the putrefying substance, I determined to of air : exclude the atmospheric air altogether. This I attempted first by the following experiment, in carbonic I put some fresh meat into a glass vessel — filled it with mer- cury— placed it in the pneumatic cistern, and filled it with car- bonic acid. In this situation it was kept three days 3 at the end of which period the flesh was found to have undergone the putrefactive fermentation 3 yet all air except carbonic acid was excluded. Though Sir John Priogle and Dr. Mc Bride (and the latter from actual experiments) contended for the antiseptic powers of fixed air. The thermometer during this experiment stood at 70. and In But as my object was to exclude oxygen gas, and as car- fcydrogen ga3. jjonic acid contains that as one of its components, I thought it nor impossible but that the animal matter might abstract a portion of the oxygen from the carbonic acid, and convert it into carbonic oxyde : as is the case with iron, zinc, tin, and certain other metals. I therefore repeated the experiment in every circumstance as before, except that I substituted hydrogen for carbonic acid gas : but with precisely the same result, putrefaction went on as well as in any of my former experi- ments, and in other * tried sulphuretted hydrogen and n itrogen gases in the same ga«e*. manner, and with the same result. I then fell upon a second method of excluding atmospheric air and oxygen gas. I to ON PUTREFACTION, 53 I took an eight ounce phial and put six ounces of fresh beef Repetition of (a portion of the diaphram) in the bottom of it, and secured it ^"P^ there. In procuring this beef I was so careful as to go to the flesh closely butcher's myself, and have it cut off the moment the animal was surrounded or t rr immersed in dead. Upon this meat while thus warrn^. and not affected by mercury. external air, I placed a column of mercury, by rilling the phial with that fluid. The phial was corked, and to the cork was adapted one leg of a syphon, which perforated the cork, all which was made perfectly air tight by luting and sealing. The syphon was filled with mercury completely, and passed into the mercurial cistern. Over this was placed a glass vessel filled with mercury and inverted, in order to collect any gas that should come over. That there was now a complete column of mercury from the meat to the top of the vessel inverted in the cistern. My object in the first place, was to prove by the first phial containing the meat covered with a col u am of mercury, whether putrefaction could take place in that situation where the possible access of air was cut off by the mercury. My object with the syphon and other apparatus was to collect and to examine the products, if putrefaction should proceed : the thermometer stood during this experiment at yo\ In about three days the putrefactive process was evidently going on. These experiments were sufficient to satisfy me, that atmos- Conclusion. pheric air or oxygen gas, is so far from being essential to putre- nei^heTewen-8 faction, that it has no influence on that process where it has tial to, nor has free access to the putrefying substance. These experiments f„ Vmrefac-' have since been repeated and confirmed by my friend Dr. tiou: Mitchill at my request. Therefore I am disposed to believe, that putrefaction must but that it is . caused by depend on the destruction of the equilibrium of attractions, changes in the which in the living state of animals exists among the elementary substance principles of which they are composed, by the loss of vitality : by which new attractions are called into action, and new com- binations and decompositions take place. My next object was to examine the products of putrefaction Products of which had taken place without extrinsic oxygen. putrefaction The first product was a bloody serum. Serum, The second was a transparent gas, possessing the transparency, Gas. elasticity, 54 ON ruTiitr ACTION, Examination of the gas from putrefac* tion : by litmus and acid ; no c ha nge. by turmeric ; no change. The gas was not absorbed by water. by sulphate oi copper ; no change. by carbonic »cid gas ; no change. elasticity, dilatibUity, compressibility, and other mechanical properties of atmospheric air. As the gaseous products of putrefaction had never been col- lected and chemically examined, 1 thought it an object of importance to give it a careful and critical analysis. I therefore proceeded to examine it in the following man- ner. As it has been the unanimous opinion of chemical philoso- phers, who have written upon the subject, that ammonia is generated, and is the principal product of putrefaction, I first tested for that substance. 1 st. By passing a piece of litmus paper, reddened by vinegar, into a vessel about half filled with this gas over mercury — no change. 2d. Some of the gas was passed through an infusion of lit- mus reddened by vinegar — no change. 3d. 1 filled a vessel with mercury over the mercurial bath, and displaced about half of it by passing up an infusion of litmus reddened by vinegar. After which I passed up the gas, which was somewhat absorbable, until it was strongly impreg- nated with it, and had accumulated in the top of the vessel — no change. 4th. 5th. and 6th. I tesied it with turmeric in all the three ways in which litmus reddened by vinegar was used — no change. 7th. I passed up a piece of wet sponge by means of a wire, but there was no perceptible absorption of the gas by the water contained in the sponge. 8th. The sponge was withdrawn and washed in a solution of sulphate of copper-r-no change. 9th. I passed up a solution of sulphate of copper into a vessel filled with mercury over the mercurial cistern until it was two thirds displaced by the solution of copper. I then passed up the gas until the solution was strongly impregnated with it and it had accumulated in the top of the vessel — no change. 10th. Carbonic acid gas was passed up into a vessel contain- ing this gas. No chemical change (except with Mr. Berthollet we call the admixture of gases chemical dissolution.) The car- bonic ON PUTREFACTION* 55 bonic acid produced an augmentation in the bulk of the gases proportional to its quantity. llth. Muriatic acid gas was passed up into a vessel filled nor by muri- wilh gas over mercury — no change. at,c aci *»as* These experiments were abundantly sufficient to prove that there was no ammonia in the products of putrefaction, at least where it takes place without the influence of external causes. Secondly, I tested it for oxygen in the following manner. Tried by phos- n , i • , *Am . phorus ; no 1st. A piece of phosphorus was passed up into a vessel filled combustion. with this gas and standing over mercury. The phosphorus was fused and became perfectly fluid, floating upon the surface of the mercury, by pouring boiling water upon the vessel. But there was not the slightest appearance of combustion. 2d. Water was now passed into the same vessel, which was tested for phosphoric acidly litmus— no change. 3d. Nitrous gas was passed into a vessel filled with this gas by nitrous over mercury — no change, except in the bulk proportional to ^jjj,J}0 1DU* the gas added. 4th. Water was now passed up into the same vessel and tested for nitric acid by litmus — no change. 5th. A mouse was passed into a vessel of this gas which by a mouie. instantly died. These experiments were deemed sufficient to prove the Conclusion; no nonexistence of oxygen. sentf"611^ Thirdly, It was now tested for sulphuretted hydrogen. 1st. A piece of silver was placed in a vessel of this gas which Silver shewed was not blackened or converted into a sulphuret when with- 11Q *ulPn« drawn. A piece of silver was also kept in water highly impreg- * nated with this gas, and one was placed at the end of the tube .from which the gas was disengaged, and with the same result. 2d. The gas was passed through a solution of nitrate of silver Nitr. of sil. n» —no change. change. 3d. A vessel was filled with mercury over the mercurial cistern, and displaced by passing up a solution of nitrate of silver until the vessel was half filled with it. After which the gas was permitted to pass up, as it was disengaged from the putrefying substance through the mercury, and through the solution of silver, until it was strongly impregnated with it and had accumulated in the top of the vessel — no change. 4tb. 56 MAKING OF COFFEE. Acet. of lead: 4th. A solution of atetate of lead in the same manner as no change. experiment 2d — no change. 5th- A solution of acetate of lend was impregnated with this gas in the same manner that nitrate of silver was in experi- ment 3— no change. Conclusion. These te&Ls were sufficient to prove that no sulphuretted No sulph hydrogen was formed. hydrog. was _ ... T , , . . formed. fourth, y, I tested it tor carbonic acid. By litmu». ist. 2d. and 3d. By fmus in all three of the ways in which litmus n ddened bv vin g«) ^as used tor ammonia- reddened. and by lime 4th. I ti Hod a vessel ^v i i ti mercury over tin bath, water ^nd passed up a quantity of lime water, after which I parsed up the putrescent gas. — The lime was precipitated. and then an 5th. The precipitate erfervesced with the era/it, sulphuric, acid- nitric, and muriatic acids. Consequently the gas is carbonic acid : Probably holding a Thegas prov- r . , ., , J r , . , x. . . . . , €d to be car- foetid oil (or some of the animal matter) in solution to which bonic. it owes its offensive odour. From the six ounces of animal substance I have already col- lected 100 cubic inches of this gas. I am, dear Sir, Your obedient servant, JOHN MANNERS. Philadelphia, Oct. 12th, 1612. XII. Of the excellent Qualities of Coffee, and the art of making it in the highest perfection. By Benjamin, Count of Rumford, F. R. S. Abridged from his ISth Essay, published in Lon- don, 1812. Praises of coffee. THE Count begins his Essay with an eulogium on coffee. He celebrates it as uncommonly agreeable in its taste, salubrious in its effects," and producing exhilaration which lasts many hours, and is not followed by sadness, languor, or debility. The glow of health, the consciousness of increased vigour of mind it affords, and the uniform experience of many able, bril- liant, and indefatigable men of the first talents in its favour — are among MAKING OF COFFEE. 57 among the topics on which the animated writer dwells in his praises of this most delightful vegetable. He acknowledges his own obligation to its powers, am! society will admit that a more cogent instance could scarcely have been adduced in support of his argument. But there is no culinary process so uncertain in- its results as The goodness that of making coffee. The same materials, in the same pro depencU great- portions, shall produce good or bad coffee according to the ly on its pre- management. If the peculiar aromatic flavour of coffee be Paratl0n : dissipated and lost, its exhilarating quality is gone, and all that would have made it valuable. To prepare it as it ought to be done, is the object of the Essay before us. Great care must be taken not to roast coffee too much. Particularly As soon as it has acquired a deep cinnamon colour, it should be ie roas ing* taken from the fire and cooled : otherwise much of its aromatic flavour will be dissipated, and its taste will become disagreeably- bitter. In some parts of Italy, coffee is roasted in a thin Florence This is best flask, slightly closed by a loose cork, and held over clear burning p[rf0y™ge/n* coals with continual agitation. No vapour issues from the coffee sufficient to prevent the progress of its roasting from being clearly seen. The Count has adopted this process by using a thin globular vessel of glass, with a long neck, which he closes, when charged, with a long cork, having a small slit on one side, to allow the escape of the vapours, and projecting far enough out of the neck to be used as a handle to turn the vessel round, while exposed to the heat of a chafing dish of coals. This vessel is laid horizontally, and is supported by its neck so as to be easily turned round ; which may be done without the least danger, however near the coals, provided the glass be thin, and kept constantly turned. In order that the coffee may be perfectly good, and very high Instruction* flavoured, not more than half a pound of the grain should be foyoasting roasted at once j for when the quantity is greater, it becomes impossible to regulate the heat so as to be quite certain of a good result. The progress of the operation, and the moment most proper to put an end to it may be judged and determined with great certainty ; not only by the changes which take place in the colour of the grain ; but also by the peculiar fragrance whick ,38 MAKtNG OF COFFEE. which will first begin to be diffused by it when it is nearly roasted enough. S nrdHm $t' ^ coffee in powder be not defended from the air,it soon loses mediately after its flavour and becomes of little value j and the liquor is never roasting. in such high perfection as when the coffee is made immediately after the grain is roasted. This fact is well known to those who are accustomed to coffee in countries where the use of it is not controlled by the laws ; and if a government be seriously dis- posed to encourage the use of coffee, the Count considers it as indispensable that individuals should be permitted to roast it in _., , their own houses. But as the. roasting and grinding of coffee coffee must be ta^es "p considerable time, the author describes a contrivance carefully pre- of a canister to keep it in, which has a double cover. This St I VCQ . vessel is a cylinder of tin, having a sliding piston within, of the same material, formed like the cover of a box, but having several slits in its sides, by which they are sprung outwards and cause it to retain its place in the cylinder with considerable force. The piston, being pressed down upon the coffee retains it and defends it from the air, while the same object is more completely secured by a common well fitted cover at top. It may be here remarked — that this kind of canister has the advan- tage of confining the article without including any air in the same space, except what may be diffused between the particles -r —but that, with this exception, a well-corked bottle or other fit vessel may answer the same purpose. Preparation of After giving instructions for roasting the coffee and keeping the beverage jt for use wnen ground, the preparation of the liquor constitutes the next subject of inquiry. Why this should be so uncertain can only be explained by reference to the circumstances on which those qualities depend which are most esteemed in coffee. A peculiar Boiiing hot water extracts from coffee which has been pro- aromatic sub- perly roasted and ground, an aromatic substance of an exquisite stance extract- ed by boiling flavour, together with a considerable quantity of astringent water, matter of a bitter, but very agreeable {aste • but this aro- matic substance, which is supposed to be an oil, is extremely volatile ; and is so feebly united to the water that it escapes into the air with great facility. W*i'Chl * d ^ a CUP °^ ^ie very kest co^ee prepared in the highest per- son fliea off. fectioh, and boiling hot, be placed on a table in the middle of a room, MAKING OF COFFEE. 5Q loom, and suffered to cool, it will, in cooling, fill the room with its fragrance j but the coffee, after having- become cold, will be found to have lost a great deal of its flavour. If it be again heated, its taste and flavour will be still farther impaired ; and after it has been heated »nd cooled two or three -times, it will be found to be quite vapid and disgusting. The fragrance diffused through the air is a proof, that the Upon this the coffee has lost some of its most volatile parts ; and as that liquor exi"|ara«ng 1 ' ^ quality de- is found to have lost its peculiar flavour, and also its exhilarating pends. quality, it is inferred, that both these qualities must undoubtedly depend on the preservation of those volatile parts which so readily escape. If the liquid were perfectly at rest, the particles which could It would not escape from its surface, would be incomparably less in quantity, jf^l^jd j\ea(j than would escape by agitation, which would continually pre- no agitation, sent new portions of the fluid to the air. But all fluids, while heating or cooling, by partial communication, are known to be agitated j a fact long and well known, but particularly ex- plained and insisted upon by our author, in many of his valuable works, and which he again perspicuously and familiarly explains in the present essay. His object is to indicate by what means the heat of the liquor may be uniformly kept up in all its parts : for the consequence being, that the parts will, in those circum- stances, be at rest, the motions by which the aromatic parts might have been dissipated, will not take place. By pouring boiling water on the coffee, and surrounding the Agitation may containing vessel with boiling water, or with the steam of boil- ^c Preve^ntc^ ing water, the coffee itself will be kept permanently at the same ing the vessel heat, and will ot circulate, or be agitated. Wlth boiling ° water or The Count observes, that from the well-known fact, that steam. boiling: water is not the most favourable for* extracting the Coftee require* , • r i • • . . -i boiling hot saccharine parts from malt in brewing, he was induced to try a water. lower temperature than the boiling heat in making coffee; but the coffee did not prove so good. The cold infusion of coffee, which he also tried, was of very inferior quality. * I have always understood, that the temperature of boiling is no otherwise exceptionable in brewing, than because it makes a pudding- ; which phrase denotes, that the grains are rendered so adherent to each other, by the sudden and complete extrication of mucilage, that the wort cannot run off— N. *Tht 6o MAKING OF COFFEE. The common The common method of boiling coffee in a coffee pot, is wasteful and neitner economical nor judicious. A large quantity of the ma- bad, terial is wasted in this method, and more than half of the aro- matic parts, so essential to its good qualities, are lost. One pound of One pound of good Mocha coffee, which, when properly make 56 cups. roastecl tfWI ground, weighs only fourteen ounces, will make, by proper management, fifty-six full cups of the very best coffee that can be made. It must be finely ground If it be not ground finely, the surfaces of the particles only will be acted upon by the hot water, and the waste will be very great, from the large proportion of coffee left in the grounds. The size of a coffee cup in England usually answers to 8-£ cubic inches, but the Count considers the gill measure as a proper standard for a cup of coffee, which he therefore adopts. This will fill the former cup to seven-eighths of its capacity, and a quarter of an ounce of ground coffee will be fully suffi- cient to moke a gill of the most excellent coffee. It is well known to chemists, that any solvent already in part charged with a substance intended to be taken up, will be less and not by cle- disposed lhan before to take up any additional quantity ; and coction. upon thisf is founded the process of percolation or straining, as is practised in brewing and other arts, and has been for some time recommended and used in making coffee. To this the Count gives his approbation. He finds, by experience, that the stratum of ground coffee to be laid upon a perforated metallic bottom of a vessel or strainer, ought to be about two- thirds of an inch thick, and to be reduced by pressure by a pis- ton or flat plate of metal (after levelling it) to less than half an inch. From the data he infers, by a chain of observations, that if the height of a cylindrical vessel or strainer be taken con- stantly at 5\ inches, the diameter of its bottom must be — To make ] cup of coffee = l£ inch— 2 cups = 2 J — 3 or 4 cups = 2f— 5 or 6 = 3 \— 7 or 8 = 4— 9 or 10 = 4-| — 11 or 12 = 5. These strainers are to be suspended in their reservoirs orves- reservoir, and sels for containing the coffee, and the whole included in another Doite"01^ lUS vesse* called tne boiler, which is to contain boiling water, kept hoi by a lamp, or otherwise. The forms of these are given with drawings, upon which it does not seem needful to enlarge in A coffee cup contains one gill. Coffee must be made by The vessels and their di mensions. A strainer, a MAKING OF COFFEE. 6l in the present abridgment, because there are several vessels of this description, with the exception of the surrounding boiler, to be found in our shops. The reader must have recourse to the essay itself for these Description of and other particulars of considerable interest, and delivered in a v,eTY RimPIe 1 and cheap ap- the familiar and perspicuous style which distinguish the vvri- paratus for tings of this author. The poor, and those who prefer simpli- making coffee. city of structure to the extremes of perfection, will be gratified by a description of his last apparatus, fig. 8. It is a porcelain, or earthern jug, with a tubular spout, not unlike those which we call milk jugs, except that these commonly have a lip-spout' (which would answer nearly as well.) Into the mouth of this is fitted a tin vessel, which fits and descends a little way down. It has a flat bottom perforated with many holes, and a good close cover j and it would be well to have a round plate or rammer, to compress the coffee on its bottom, and defend it from the stream of hot water, when poured in. These several parts are to be dipped in boiling water before using, and the difference between coffee made by this simple and cheap appa-. ratus, of which the mug may also be applied to other uses, and that made by the the most perfect machines, will scarcely be distinguishable. Sufficient length has already been given to our abstract, to General con- forbid us to follow the Count in the explanation of his views sidcrations or directed to the benefit of society, with relation to the com- jng thebeue- forts of individuals, as well as to the economy of the political fits of coffee, aggregate. That it would be preferable to consume an article produced by the colonies of European nations, who demand the manufactures and products of the parent -state, instead of sending bullion to China for an article of less value: that it would be preferable that the poor should enjby the innocent exhilaration of coffee, and the nutriment of sugar, instead of forgetting their hardships during the momentary intervals of insanity, produced by fermented and distilled liquors j that they should be cheerful, benevolent, animated, healthy, and indus- trious with coffee, instead of becoming outrageous, mischievous, diseased, idle, and sunk in languor and debility with gin, &c.,&c. ♦ These are among the meditations interspersed through this little work, which the reader will be gratified in consulting, and will probably be induced to make others iu his turn. XIV 62 METEOROLOGICAL JOtfRtfAt* XIV. METEOROLOGICAL JOURNAL, B AliOMETER. TlIKRMOMETEK. j 1812. Wind Max. Min. Mid. Max. Mr* Med. 10th Mo. Oct. 27 S W 2040 29-24 2932O 52 40 46-0 28 s \v 2975 •J9'40 29-575 51 32 41-5 29 w 29SO 20/4 29-770 "49 33 4 10 30 S E 2978 296O 29-720 51 39 45 0 31 W 2994 297S 29 boo 54 41 475 Uth Mo. Nov. J s w 2994 29-87 29905 55 50 52-5 2 N 3005 2987 29960 54 44 49O 3 s w 49 38 43-5 4 w 30-05 29*80 29.940 48 39 43 5 5 N W 29\83 29- 80 29-815 49 30 395 6 S \V 29 83 2C)- 80 29-815 45 27 360 7 W 29 S3 2979 29 810 45 24 345 8 E 2979 2977 29780 40 27 33'5 9 E 46 39 42-5 10 N E 30" 15 30 03 30090 45 33 390 11 S E ■ 46 3Q 425 12 E 30 03 29'58 29-805 45 39 420 13 N E 29'58 2920 29390 51 44 475 14 W 29'59 29-20 29,395 52 40 460 15 s \v 29'59 2930 29445 52 39 45 5 10 N E 2930 2t)00 j 29-150 40 42 440 17 N E 29'CO 28*96 289SO 46 40 43 0 18 N \V 29-66 2S9O 29310 42 32 370 10 N 29-86 29-66 2976O 42 28 350 20 N 29-9; 29-83 29.900 41 33 370 21 N E 30 32 29*97 30145 39 26 32-5 22 N 30-38 3031 30345 43 25 340 23 S W 303 1 3008 30'195 44 26 350 24 s w 3008 3038 29-89 28-96 29985 48 39 435 29-678 55 24 4131 Rain •20 _ _ •14 •7 •65 8 5 ^mm •32 — •38 — ■55 — — — 3 — — 7 •13 7 9 058 246 0 The observations in each line of the table apply to a period of twenty-four hours beginning at 9 A. M. on the day indicated in the first column. A dash denotes, that the result is inch ded in the next following observation. METEOROLOGICAL JOURNAL. REMARKS. Tenth Month, 27. Misty and overcast a. m. p. m. the Barometer descended at the rate of a tenth of an inch per hour, the wind increasing in proportion, with much rain, the clouds sweeping the earth. The evening was very- tempestuous j before midnight the Barometer had risen again and the weather was moderate. Many large trees were blown down. 28. a. m. hoar frost rather misty. At sunset, the sky exhibited a fine collection of coloured clouds, in the modifica- tions Nimbus and Cirrus, with broad parallel bands of red in the haze above them. 28. Fair and calm. 30. Cirrostratus and Cumulus : the sky again beautifully coloured. Eleventh Month. I. Cloudy. 2. a. m. wet. 5. Fine day. 6. 8, 9, 10, 11. Chiefly misty or cloudy, with hoar frost, and some very thick local fogs. 11. Overcast, a. m. l*ie Cirrostra- tus prevails, and sounds travel with the wind to an unusual distance : we hear the rattling of the carriages on the pavement in London through a direct mean distance of five miles. This phenomenon is to be attributed to a thick continuous sheet of haze in the air above us which acts as a sounding board. 12. Rain through the day. 13. Misty : rain : sounds are again distinctly heard from the city. 15. Fair : a Stratus at night. 10'. Overcast ; with an easterly gale. 18. Wet stormy day, night clear and calm. 20. Misty, much rime on the trees, which came off about noon in showers of ice. At 1 1 a. m. a perfect but colourless how in the mist: near 4 p.m. there was a shower, in which the rainbow shewed its proper colours. 22. Clear : the ground just sprinkled with hail balls. 23. a. m. misty rime. p. m, clearer, thaw in the night. 24. Clear morning. RESULTS. Vfnds for the greater part westerly ; though the rain chiefly fell during an easterly wind. Barometer : highest observation, S'J'otf inches; lowest 23*96 inche» j .Mean of the period £9*67Q inches. Thermometer : highest 55° ; lowest £4*. mean •ll'SJ.0. Evaporation O'o8 inches. Rain &46 inclu ft, ri.AisTow, L. HOWARD. Ticdnb Month, is, 1812. 63 64 IMPROVED PUMP. Improved pump for •inking of wells, mine- shafts, Sec. XV. Description of an improved Pump for raising the Water from Wells or Mines, while sinking o? making. By Mr. William B run ton, of Butter ley Iron Works, in Derbyshire*. Ex- traded from the Transactions of the Society of Arts, pub' lished in the Year 1812. THE contriver of this pump, previous to entering upon a description of his drawings, gives the following statement of the inconveniences he proposes to obviate. First, as it is necessary for the pumps, whilst sinking, to be always working upon air, that the water may be kept very low in the pit, the engine of course frequently goes too fast, and carries up, by the violence of the current, small pieces of stone, coal, of* other substances, and lodges them abofe the bucket, which must considerably retard the working of the pump, and wear the leather, Secondly, When the engine is set to work, (after having been stopt whilst working upon air, and consequently a quantity of air remaining in the suction-pipe, with the small stones, &c. deposited on the valves of the bucket) it often happens, that the compression of the air, by the descent of the bucket, is not sufficient to overcome the weight of the bucket valves so loaded with rubbish, and the column of water in the stand pipes, the pump is hereby prevented from catching its water > the usual remedy for which is, to draw the bucket oui of the working barrel, until a quantity of water has escaped by its sides, and displaced the air. Observe here, that tint oiten hap- pens from the unnecessary magnitude of the space between the bucket and clack. Thirdly, The pumps are suspended in the pit by capstan ropes, for the purpose of being readily lowered as the pit is sunk j the stretching of the ropes, (especially when . sinking in soft strata,) occasions much trouble, by suffering the pumps to choke j but the most serious evil is, that the sinkers, in shifting the pumps from one place to another, throw them very far out of perpendicular, thereby causing immense friction, • For which the »ilver medal was voted. and IMPROVED PUMP. and wearing in all the parts -, besides endangering the whole Improved apparatus, by breaking the bolts and stays, and straining the P?™P fo,*p joints. * wells, mine- Fourthly, As the pumps sink, the delivering pipe at the top shafts, &c, is raised, by putting on short pipes, generally about a yard at a time, which occasions many stoppages and much hindrance in the work. Having an engine pit to sink at Codnor Park Colliery, Der- byshire, belonging to the Butterley Iron Company, I endea- voured to obviate the difficulties stated ; and first, for the. pur- pose of preventing the pumps working too much upon air, 1 constructed a working barrel, (which in this case was nine inches diameter,) AVith a side pipe three inches diameter, con- nected therewith by an opening at the top and bottom ; also at the upper end of the side pipe I fixed a valve, so as to slide over and snut the communication with the working barrel, the Stem of the valve by which it is regulated, passing through a stuffing box, and by letting a quantity of water return through the side pipe to the bottom of the working barrel, (the men at the bottom regulating the valve, so that the pump takes the water as it comes,) very little rubbish is then taken into the pump, and much wear and tear of buckets prevented. Secondly, t also, by this valve and side pipe, preclude the necessity of ever drawing the bucket to displace the air. The clack piece was made as small as possible, and the clack with its gearing very low, in order to have as little space as possible between the bucket and the clack. The clack, as represented in the drawing, possesses the advantages of being easily caught by the clack hook in case of being under water. The ring" prevents it from oversetting, and thereby fastening itself in the pumps and the valves are very easily repaired by unscrewing the cross-bar, which admits of their being taken off and re- placed. Thirdly, I avoid the inconvenience of suspending the pumps by ropes, by forming the suction-pipe in two pieces, one inner and outer pipe ; the outer pipe is bored for about six inches in length, and the inner one turned cylihdrically to fit it; they slide into each other the whole length of a regular pipe, viz. nine feet : and they are made tight by collars of leather, surrounded by a cup filled with water and clay. The Vol.XXXIV.-No.156. F pumpe 65 66 IMfROVED fUMP, Improved pump for sinking of wells, mine- shafts, &c. pumps are supported at proper distances, so as to suit the length of the pipes, by beams, and across those are other beams, upon which the flanches of die pipes rest : these last are not fastened by any bolt, in order that they may be readily removed. The pumps, by these means, remain stationary, and the suction-pipe lengthens as the pit is sunk, until it is drawn out to its full extent. The whole column is then lowered to the next flanches, and another pipe is added to the top j the lower end of the suction-pipe is formed somewhat like a crank, in order that the sinkers, by turning it round upon the other pipe, may move it from one place to another, and so prevent the necessity of sinking immediately under it. Fourthly, The pumps being stationary, as above stated, the pipe at the top will of course deliver the water at the same level at all times, and instead of being obliged to lengtherf the column every yard sunk, it will only be necessary every nine feet. Fig. 1 . PI. II, is the section of a shaft or pit, with the pump fixed in it j it is cast in lengths of nine feet each, screwed to- gether by flanches, and supported by beams extending across the pit, (as shown in the plan, fig. 6,): short pieces are laid across these, with half circular holes in them j and these being put round the pump, just beneath a flanch, sustain the pump firmly, but may quickly be removed when it is required to lower the pumps in the pit j and, as they are not fastened, they do not prevent the pumps being drawn upwards j A, fig. 1, is a door which unscrews, to get at the lower valve or clack of the pump j this is more clearly explained in the enlarged section, fig. 2, where A has the same designation, B, rig. 2, is the working barrel, with the bucket D working in it \ E is th« clack, also shewn enlarged in figs. 3 and 4 j F is the suction- pipe, and GG the moveable lengthening piece \ this slides over, and includes the other, as in fig. 2, when the pump is first fixed ; but, as the pit is sunk, it slides down over the pipe F, to reach the bottom, as in fig. 1 ; the outside of the inner pipe F is turned true and smooth, and the inside of the outer pipe G, at the upper end, is bored out to fit it -, the junction is made perfect by leathers placed in the bottom of the cup a a, which holds water and wet clay over them, to keep them wet and pliable, and consequently air-tight -, the lower extre- mity IMPROVED PUMP. 67 mity of the suction-pipe G, terminates in a nose, pierced with improved a number of small holes, that it may not take up the dirt : this pump for nose is not placed in a line with the pipe, .but curved to one ^ej)s m;ne. side of it, so as to describe a circle when turned round 5 by shafts, &c this means the sinkers can always place the nose in the deepest part of the pit, as shewn in fig. 1 ; and when they dig or blast a deeper part, they turn the nose about into it, the sliding tube lengthening down to reach the bottom of it : by this means there is never a necessity to set a shot for blasting so near the pump foot, as 10 put it in any danger of being injured by the explosion, as is the case in the common pump j in which this danger can only be avoided by moving the pump foot to one side of the pit, which necessarily throws the whole column of pumps out of the perpendicular. The construction of the clack is explained by figs. 3 and 4, the former being a section, and the latter a plan j LL is a cast-iron ring, fitting into a conical seat in the bottom of the chamber of the pump, as shewn in rig. 2j it has two stems, //, rising from it, to support a second iron ring, M M 5 just beneath this, a bar, m} extends across from one stem to ano- ther, and has two screws tapped through it j these press down a second cross-bar, n, which presses the leather of the valves down upon the cross-bar of the ring L, and this holds it fast, forming the hinge on which the double valves open, without the necessity of making any holes through the leather, as in common -, but the chief advantage is, that, by this means the clack can be repaired, and a new leather put in, in far less time than at present, an object of the greatest importance 5 for, in many situations, the water gathers so fast in the pit, that if the clack fails, and cannot be quickly repaired, the water rises above the clack-door, so as to prevent any access to it, and (here is no remedy, in the common pump, but drawing up the whole pile of pumps, which is a most tedious and ex- pensive operation. In Mr. Bruntoa's pump, the clack can at any time be drawn out of the pump, by first drawing out the bucket, and letting down an iron prong, fig. 5, which has hooks on the outsides of its two points j this, when dropped down, will fall into the ring M, and its prongs springing out, will catch the underside, and hold it fast enough to draw it up; another part of Mr. Brunton's improvement consists in the F 2 addi- 68 WATER IN MURIATIC ACIt> GAS? Improved addition of a pipe H, fig. 2, which is cast at the same time with sinking of tne barrel, and communicates with it both at the top and at the \vells, mine- bottom, just above the clack ; at the upper end the pipe is covcr- ' * ed by a fl.it sliding plate, which can be moved by a small rod, b, passing through a collar of leather ; the rod has a communi- cation by a lever, so that the valve can be opened or shut by the men in the bottom of the pit ; the object of this side pipe is to let down such a proportion of the water, which the pump draws, as will prevent the pump drawing air ; though of course the motion of the engine will be so adapted, as not to f require a great proportion of the water to be thus returned through the side pipe j yet it will not be possible to work the engine so correctly, as not to draw some air, without this con- trivance j and if it does, it draws up much dirt and pieces of stone into the pump, besides causing the engine to work very irregularly, in consequence of partially losing its load every time the air enters the pump. Another use of the side pipe is, to let down water into the chamber of the clack to fill it, when the engine is first set to work, after the pumps have been standing still, and the lower part of the barrel and chamber empty*. XV. An Account of an Experiment made in the College Laboratory , Edinburgh, drawn up by Joijn Davy, Esq. SIR, If water be 1F"N the preceding numbers of your Journal, several papers have the conTbiuZ "^" aPP^ared> relative to the result of the combination of nation of mur. muriatic acid and ammonia. Mr. Murray first made the expe- a. gas, and riment, for the purpose of ascertaining the nature of the anim. gas, the ' ~ * * & viur.a.gas former gas — whether it be a compound of an unknown basis contains none. ancj water> or a compound of chlorine and hydrogene. He * This communication was accompanied by a handsome letter from that eminent civil engineer, William Jessop, Esq., who, after explaining the usual practice and the effect of Mr. Bruntons improvement, adds, that simple as it is, it will be found, as he has from experience ascer- tained, to be of considerable value to those interested in mining con- cerns. justly WATER IN MURIATIC ACID GAS ? ()Q justly conclude 1, that if water was obtained from muriatic acid Mt, by means of ammonia, its existence in the acid must be admitted ; and that, on the contrary, if no water could be pro- cured, it would be nnphilosophical to suppose water present ; but that muriatic acid gas must be considered as a compound of hydrogene and chlorine. Such were Mr. Murray's pre- mises. The result of his experiment, he says, was the production Asserted fart - „ . . c . c , , ' , . t>y Mr. Miir- of water lrom the muriate or ammonia, formed by the union r^ that thr of the dry gases. He therefore, of course, concluded, that dry gases af- muriatic acid gas is not a compound of chlorine and hydro- conch lusion, gene, but of water and an unknown basis (muriatic acid ;) that m. «. ga$ in fact, that the old doctrines respecting this substance, ^?*r *** * which he had strenuously defended before, are correct, and the new theory advanced by Sir H. Davy, erroneous. This experiment was also repeated on a very small scale at Liverpool, by Drs. Bostock and Traill, and with nearly the same result. But other results have been obtained. — Sir H. Davy has Sir H.Davy made the experiment several times, and under different circum- afd the writer ' obtained no stances ; and has uniformly pei ceived no water, when the at- water. mospheric air was excluded, and dry vessels, and dry gases were employed • and my experience is agreeable to his, having been unable to obtain any water the only time I repeated the expe- riment, on subjecting the muriate to a heat not sufficient for its sublimation, though water was procured by heating the same salt, after it had been exposed to the atmosphere. It is not my object at present to attempt to reconcile these contradictory results, or to show, by any process of reasoning or criticism, that Mr. Murray has fallen into errour. It is my intention to confine myself to the concise detail of new ex- periments, which will tend, I trust, to decide the question. About two months since, when my brother, Sir H. Davy, Repetition of* wa3 in Edinburgh, he was desirous of repeating the experiment the experi- on the combination of muriatic acid and ammonia, with Dr. me™ b*fore eminent men, Hope. The experiment was accordingly made in the College Laboratory.— Sir George Mackenzie, Mr. Playfair, and some other gentlemen, were present. The alkaline and acid gases employed, were pure, and both The amm ga» had previously been dried by exposure, for about sixteen hours, was dned b* to yQ WATER IN MURIATIC ACID GAS ? potash ; the substances having a strong attraction for water — the ammoniacal mur. a gas by gas to pieces of potash — and the muriatic to dry muriate of They were in nme. The apparatus for making the experiment consisted of alternate por- a plain retort of about the capacity of twenty-six cubic inch in°an exhaust- measures* wUh a stop-cock; and of a receiver, with a suitable -ed vessel. The stop-cock. The latter was filled over mercury with one of the wwdrlven gases> which from the receiver passed into the exhausted from the neck retort, by means of the stop-cocks j the other gas was Intro- °f jtl!tv?ssel ' duced the same way into the retort : and thus alternately about and this being J ' J cooled, and ninety cubic inches ot each gas were combined. The muriate the body heat- 0f ammonia formed, was of its usual appearance. As it. was diffused over the whole surface of the retort, it was necessary to clear the neck by the sublimation of the salt into the bulb, that if any water was present, it might be detected here in the . second part of the operation. All the salt being driven into the bulb of the retort, by the heat of a spirit lamp, the neck was cooled and kept cold -by moistened cloths, whilst the buib was heated by a coke-fire, till the muriate began to sublime, and to make its appearance at the curvature of the vessel. The fire was now withdrawn. It had been gradually and equally applied, and it had been con- tinued for a considerable time, a dew, just The result was examined whilst the bottom of the retort was perceptible, still very hot, and whilst that part, where a little of the muriate the neck had sublimed, exceeded the temperature of boiling water. A dew just perceptible was observed lining the cold neck. The quantity of water was so extremely small, that the globular particles composing this dew could scarcely be perceived by the naked eye, unassisted by a magnifying glass. This result appeared to me very decisive. The quantity of gases employed was large -, the water, which ninety cubic inches of muriatic acid gas should afford, is,- according to hy- pothesis, equal to no less than-eight grains. How great is the difference between this quantity and a dew barely perceptible ! which may reasonably be referred to a minute quantity of va- pour in the gases, or to a little moisture derived from the mercury, a small quantity of which entered the retort with the gases, -which seemed Dr. Hope wished to ascertain how much water would pro- about oue- duce such a de\v as was observed. For this purpose he heated in WATER IN MURIATIC ACID GAS ? J ] in a retort, of a similar size to that used in the experiment, sixth of a a single drop of water, which it may be said weighs about 1 gram« grain. The appearance of condensed water in this instance in the neck of the retort, was much greater than in the preceding; he thought that it was 3 or 4 times as great. May we not conclude from these results, on Mr. Murray's Deduction : own ground of reasoning, that water is not a constituent part °f notVconati- irrai iatic acid gas, and that this substance is a compound merely tuent part of of chlorine and hydrogene ? And may we not reasonably con- jj™1^ * gas-; sider that very minute portion of water, which did appear, as comp. of tincombined moisture derived from various sources ? It is fh,orme afld Jiydrogene. easy to account for the presence of about ^ of a grain of water on the one theory; it is impossible to account for the absence of ■8 grs. on the other. It has been shewn, by Dr. Henry, that ammonia obstinately retains aqueous vapour j and Sir H. Davy has proved, that a minute portion of solution of muriatic acid in water, may be obtained by intensely cooling the gas. There is great difficulty in drying mercury without boiling it ; and in the present instance the mercury was not boiled. These trivial circum- stances do not deserve notice, otherwise than as tending to account for the very minute quantity of water obtained. It is probable, judging from the past, that objections will be made, and I wish to anticipate them. The present mode of heating the muriate of ammonia in If water na(j a close retort, which had also been adopted on a former occasion, been present it was objected to in a preceding number of your Journal. Mr. ^"^ iav* Murray there observed, that in consequence of the air being confined, it was possible that the water could not rise in vapour, or at least that it was impeded in its volatilization. His reason- ing was subtile, and it would have been plausible had there been no circulation cf air in the vessel, and quite correct if the heat employed had not been sufficient to convert the water into an elastic fluid or true gas. — But in a large retort such as we used, there is a circulation of air, when heat is partially applied; and the heat employed was far above that required for boiling water. Not to dwell on reasonings, which on controverted points are £xper;ment in always very justly to be suspected, I shall have recourse to fact, proof. A single drop of water was introduced into a retort, about t]ie same size as that employed in the experiment, and it was tightly 72 SCIENTIFIC NEWS. lightly stopped by a cork. On the Application of heat to the bulb, the water passed off into steam apparently wiih the same velocity that it would have done, had there been a free com- munication between it and the atmosphere, and o( course the steam was just as readily condensed. This experiment was suggested and made by Dr. Hope. I have now finished the account of the experiments which f wished to communicate, and as I have no intention of answer- ing personal aspersions, which are only injurious to the author when unjustly made, nor of entering again into a controversy- concerning words, I shall here conclude with subscribing myself, Your obedient humble servant, JOHN DAVY. Edinburgh, December 9. To Mr. Nicholson. P. S. I have authority from Dr. Hope, and also fiom Sir George Mackenzie and Mr. Playfair, to mention, that the detail I have given of the experiment is correct. I should have before observed, that the muriate was heated in the preceding experiment in a, partial vacuum. After the: combination of the two gases had been formed, a little ammonia remained in the retort, and to this as much air was admitted, as was conceived sufficient when the heat was applied, to pro- duce the common atmospheric pressure. SCIENTIFIC NEWS. Account of Books, &c. Philosophical Transactions of the Royal Society of London, fur the year 1812. Part II. 4to. 187 pages, with 12 plates. THIS part contains the following paper. 1 . Observations of a second Comet, with remarks on its construction. By William Herschel, LL. D. F. R. S. 2. Additional Experi- ments on the Muriatic and Oxymuriatic Acids. By William Henry, M. D. F. R. S. &c. (See our present volume, p. 42.) 3. Of the Attraction of such Solids as are terminated by planes ; and SCIENTIFIC NEWS. and of solids of greatest attraction. By Thomas Knight, Esq. 4. Of the Penetration of an Hemisphere by an indefinite num- ber of equal and similar Cylinders. By Thomas Knight, Esq. 5. On the Motions of the Tendrils of Plants. By Thomas Andrew Knight, Esq. F. R. S. (See our present Vol. p. 37.) 6. Observations on the Measurement of three degrees of the Meridian conducted iu England by Lieut. Col. William Mudge. By Don Joseph Rodriguez. 7. An account of some Experiments on difFerent Combinations of Flupric Acid. By John- Davy, Esq. 8. On a Periscopic Camera Obscura and Microscope. By William Hyde Wollaston,M. D. Sec. R. S. (See our present vol. p. 26.) Q. Farther Experiments and Observations on the Influence of the Brain on the generation of animal heat. By B. C. Brodie, F. R. S. 10. On the different Structures and situations of the solvent Glands, in the digestive organs of Birds, according to the nature of their food, and particular modes of life. By Everard Home, Flsq. F. R. S. 1 1 . On some Combinations of Phosphorus and Sulphur, and on some other subjects of Medical Inquiry. By Sir H. Davy, Knt. Sec. R. S. List pf Presents. Index. The History of the Royal Society from its Institution to the End of the \Slh Century. By Thomas Thomson, M. D. F. R. S. L. and E. 2 vols. 4to. price 21. 2s. and on fine paper, 31. 12s, Mr. Andrew Horn, of Wycombe, acquaints me that he has a short Essay on Vision in the press, in which the Seat of Vision is determined, and by the discovery of a new function in the organ of Sight, a foundation is laid for explaining its mechan- ism and the various phenomena, upon principles hitherto un- attempted. Bionomia. Opinions concerning Life and Health, introductory to a Course of Lectures on the Physiology of Sentient Beings. By A. P. Buchan, M. D. of the Royal College of Physicians, London, 8vo. lip pages, with 8 p. Introduction. Where the master of a science, not to be acquired without deep erudition, a diligent and correct observation of facts, and an enlightened spirit of philosophical research, takes his station 73 7-i SCIENTIFIC NEWS. station on an eminence, and by a few striking outlines gives a sketch of the prospects around him, it becomes impossible to make an analysis of his work. I mast therefore confine myself to say, that this treatise contains many important and highly interesting truths, delivered with perspicuity and elegance. M. De Luc's Geological Travels in Germany^ France, and Switzerland, are nearly ready for publication. A work on Oriental Commerce, in two 4to. vols. By Mr. Milburn, with numerous Charts, by Arrowsmith, is expected to be published in a few weeks, Tyrocimum medicum ; or a Dissertation on tlie Duties of Youth, apprenticed to the Medical profession. By William Chamber- lay ne, Member of the Royal College of Surgeons, Fellow of the Medical Society of London, &c, duodecimo, 253 pages, London, 1812. This familiar and very perspicuous Dissertation, contains much more than is indicated in the title. It is a subject of primary interest to the public, that the preparation and dispensing of medicines should be done with fidelity, precision, and dispatch. It is of equal importance that the professors of the art should not be deficient in the requisite information. But in every class and every rank of Society, the habits of order, method, cleanli- ness, punctuality, and other good qualities, which have been called the minor virtues, are so essential to prosperity and hap- piness, that a book which strikingly displays their advantages, must be considered as of much more extensive utility than any set of Aphorisms confined to an individual profession. The good advice with which this Treatise abounds, is calculated to afford great benefit to the reader, whether intended for the Medical profession, or for any other department of life. M. Zambeccari, accompanied by a friend, ascended in a bal- loon from Bologna, on the 21st September. On his descent, the balloon became entangled in the branches of a high tree, and, before it could be disengaged, caught fire. The two aero- nauts leaped out. M. Zambeccari was killed upon the spot ; but SCIENTIFIC NEWS. 7^ but M. Bologna, his friend, survived, though some of tas. limbs were broken. The ascension of Bittorf, the mechanician, from Manheim, was equally disastrous. When he had risen to a considerable height, he perceived, too late, that his balloon was damaged, and he had no other resource than to open the valve. The balloon descended with extreme velocity, and the inflammable matter which it contained, took fire, the shreads of the bal- loon falling upon M. Bittorf's head and breast, which were much burnt. On a sudden, his crazy vehicle struck upon the roof of a house, two stories high, from which he was pre- cipitated, and died the next day in great agony. Mr. Sadler, the aeronaut, ascended from Belvidere-house, near Dublin, October 1 , at 1 p. m. with the wind at south- west, and in thirty-five minutes had sight of the mountains in Wales ; he continued in the same direction till three o'clock, when being nearly over the Isle of Man, the wind blowing fresh, he found himself fast approaching the Welch coast ; and at four o'clock, he had a distinct view of the Skerry light- house, and the prospect of consummating his ardent hopes of a speedy arrival in Liverpool. The wind now shifting, he was again taken off, and lost sight of land j when, after hovering about for a long time, he discovered five vessels beating down channel ; and in hopes of their assistance, he determined on descending with all possible expedition, and precipitated him- self into the sea. In this most critical situation he had the mortification to find the vessels took no notice of him : obliged, therefore, to reascend, he now threw out a quantity of ballast, and quickly regained his situation in the air, to look out for more friendly aid. It was a length of time before he bad the satisfaction of discovering any , and then observed a vessel, which gave him to understand by signal, that she in* tended to assist him, but could not reach him. Two others also now appeared in sight, and one of them tacking about, hoisted the Manx colours : night now coming on, he was de- termined to avail himself of their friendly aid, and once more descended into the sea j but here the wind acting upon the balloon, as it lay on the water, drew the car with so much velocity, that the vessel could not overtake it ; and, notwith- standing SCIENTIFIC NEWS. standing he used his utmost efforts, and latterly tied his clothes to the grappling-iron, and sunk them to keep him steady f still the balloon was carried away so fast, that he was under the necessity of expelling the gas ; upon that escaping, the car actually sunk, and he had now nothing but the netting to cling to. His perilous situation, and the fear of getting entangled, deterred the men from coming near him j until, being in dan- ger of drowning, Mr. Sadler begged they would run their bow- sprit through the balloon, and expel the remaining gas. Hav- ing done this, they threw out a line, which he wound round his arm, and was then dragged a considerable way before they could get him on board, quite exhausted, A meteoric stone, of the weight of 15lbs. fell to the earth on the 1st of March, 1811, in the village of Konleghowbk, dependent on the town of Romea, in the government of Tschernigoff, in Russia, and making part of the domains of Count Golovkin. Its fall was preceded by three violent claps of thunder. When it was dug out from the depth of more than three feet, through a thick layer of ice, it still possessed heat. It was remarked, that at the third clap of thunder there was qn extraordinary explosion, with aloud noise, and throwing out 3 great quantity of spares. A new comet was discovered by M. Pons, of Marseilles, on the 20th of July. Its course was then between the feet of the Camel-leopard and the head of the Lynx. It was discovered afterwards at Paris, by M. Bouvard j and, according to th# calculations of these astronomers, it passed its perihelion on the 15th of September, when its distance from the sun, taking that ©f the earth at unity, was at 0,77.835, and its inclination to the ecliptic is 74° 50'. The Geological Society held its first meeting of the present session on Friday, November 6th, 1812. A second letter from Ed. L. Irton, Esq., in answer to some queries by the President, relative to the sand tubes found at Drigg, in Cumberland, was read. From SCIENTIFIC NEWS. 77 From this it appears, that the tubes have hitherto been found only in a single hill of drift sand on the sea-shore, of the ex- tent of about five acres. The entire form of the tubes is not known ; for they are discovered in consequence of being laid bare by the drifting of the sand j and the same cause almost always breaks off, and injures their upper extremity. The manner in which they terminate below, is still less known : one of the tubes was exposed by hazardous digging, in running sand, to the depth of about fifteen feet, without the least ap- pearance of its being about to terminate. They lie parallel to each other, and nearly vertical, but at unequal distances — the number must be very considerable, Mr. Irton having himself taken away, at different times, not less than a hundred. The tubes, when first dug out, are very flexible, but exposure to the air for a fqvv seconds deprives them of this quality. The unctuosity of the internal glazing of these tubes, when re- cently dug up, stated by Mr. Irton, in his first letter on the authority of another person, appears, on more accurate exami- nation, to be a mistake. A communication from George Cumberland, Esq., relative to some limestone strata in the neighbourhood of Bristol, was read. The strata here described compose the rocks opposite to the Hotwell Walks, and are farther illustrated by two drawings ; the one of the external face of the rocks, the other of a large cavern recently discovered. In clearing the ground for the erection of houses opposite to the Old York hotel, on Clifton downs, some interesting varieties of sulphate of strontian were met with, but the place being now covered with building and garden grounds, there is little likelihood of its being soon again opened to the researches of the mineralogist. A communication, accompanied by three drawings in illus- tration, from Dr. Mac Culloch, Mem. G. S. relative to a re- markable interrupted vein in lime -stone, was read. This vein occurs in a mill-stone which was shipped from Limerick, and is at present at the royal powder mills at Wa!- tham Abbey. The stone itself is a dark blue slaty limestone, containing comminuted fragments of marine remains; the yeiu by which it is traversed is whjtish compact carbonate of lime. This vein, in its present state, consists of a number of separate .angular 78 SCIENTIFIC NEWS. angular fragments, having somewhat of a general parallelism with such a correspondence at any two neighbouring extremities as to render it a matter past doubt that they have once formed a continuous vein. To displace such a vein into its present position, it is necessary to suppose that the rock originally consisted of a series of very thin strata, which, being fissured across, formed a spice for the reception of the substance of the vein. It is evident from the angularity and the irregularly-serrated edges of the displaced fragments, that the white calcareous carbonate must have been perfectly indurated at the time of its displacement : yet that the strata of the limestone must have been in a state to admit of a series of shifts or slides, each successively advancing with equal intervals beyond the one preceding it : it is necessary also to suppose that the strata must have been in some condition admitting them to cohere intimately together, either at the period when the slides took place, or afterwards, from the per- fect obliteration of the seam. By what theory can these facts be explained ? Friday, Nov. 20. A communication from Ar. Aikin, Esq. Sec. entitled f Some observations on abed of Greenstone, near Walsall, Staffordshire, was read. The Greenstone, which is the subject of this paper, is of a dark blackish-blue green colour, has a glimmering lustre, and an uneven fracture, breaking into irregularly wedge-shaped blunt-edged fragments : it is tough, acquiring a kind of polish under the hammer, is moderately hard, and rather heavy. It strongly attracts the magnetic needle, and effervesces on immer- sion in cold diluted muriatic acid. It consists pi incipally of felspar, mixed with calcareous spar, with minute shining black grains of Augite, and of hornblende. It is penetrated by nearly vertical contemporaneous slender veins of calcareous spar, and after a few weeks exposure to the air acquires a liver-brown colour and falls to pieces. It occurs in the independent coal formation ; but is not co- extensive with this formation ; nor indeed in the opinion of the author of the paper is it to be considered as a true bed, but rather a lateral vein branching off from a large dyke of green- stone that comes up to the surface, dividing the colliery in which the greenstone bed is, from another adjacent to it. On SCIENTIFIC NEWS. ?f) On comparing the strata above and below the greenstone, with the very same strata that have been pierced through in a part of the colliery where the greenstone does not occur, it v appears, that the bed of slaty clay with balls of ironstone lying upon the greenstone, does not materially differ from the same bed where the greenstone is absent, but that the beds immediate- ly below the greenstone, present very different characters where, they are covered by this latter from what they do where the contrary is the case. These beds are 1. Sandstone, 2 Bituminous ahale, with slender seams of coal, and 3. a coal somewhat more than a yard thick. Of these the sandstone is considerably indurated, the bituminous shale is also indurated, entirely deprived of bitumen, and is broken more or less into irregular pieces, and mixed with the lower part of the sandstone bed. The yard coal is also entirely deprived of bitumen, is stained and irridescent on the surface of its natural joints, and is more friable. These changes appear to accompany the superposi- tion of the greenstone bed through its whole extent, and from the circumstance of their ceasing where the greenstone termi- nates, they appear to be occasioned in some way or other by this bed. Scientific Institution, Princes Street, Cavendish Square. On Tuesday, Jan. 5, Mr. Singer will begin his course of twelve Lectures on Electricity and Electro-chemical science, which will be continued upon each subsequent Friday and Tuesday, until concluded. And on the 23d of i'eb. he will begin his course of Voltaic Electricity. In addition to the extensive apparatus before employed, he has now in forwardness an entire new Battery of one thousand double plates, with a variety of auxiliary apparatus. Anatomical Theatre ; Lower College Street, Bristol. Mr* Thomas Shute will commence his spring course of Lectures on Anatomy, Physiology, and the principles and opera- tions of Surgery, on Saturday the 8th January, at eight in the morning. Dr. Buxton will commence his spring Course of Lectures oft the Practice of Medicine, about the 20th of January next. SO SCIENTIFIC KE^S. s The Pontine Marshes. It is announced, from the Continent, that the French havtf tucceeded in draining the Pontine Marshes ; a pestilential nuisance which has subsisted for so many centuries, in the vicinity of Rome, in defiance of every attempt of the ancient Imperial, as well as of the papal government. This district, once so healthy and so populous, and at length again reclaimed, is said to afford a disposable quantity of 150,000 acres of excellent land. The means adopted are not, nor perhaps can he, clearly stated in a short notice. That the Engineers have improved the line -, regulated the falls j enlarged the water ways j secured the embankments, sluices, and other works ; and no doubt, employed the powers of steam to facilitate their general and particular labours — may be concluded from the science and activity of a people, too long employed in the works of destruction. To works like the present every friend to humanity must join in wishing success and duration. William Davis's Treatise on Land Surveying, to which are how first added a supplement, and a portrait of the Author, the fifth edition greatly improved, enlarged and better arranged is nearly ready for publication. Mr.Bakewell will commence a course of Lectures on Geology and Mineralogy, at the Surry Institution, in January, 1813. v Mr. Nicholson takes this opportunity to acquaint his Patrons and Correspondents, that he has been, for some time, occupied upon such arrangements, with regard to his public undertakings and other concerns, as have enabled him to take the conducting and editing of this Journal entirely into his own hands ; which, for some time past, have, in a great measure, been committed to an eminent and able scientific gentleman, who is not at present engaged in the work. The whole of the annotations and remarks, together with various original as well as abridged and selected articles, on different subjects, will consequently , as in times past, be produced by Mr. Nicholson ; and he looks forward with con- fidence and pleasure to many a renewed correspondence on the subjects of natural Philosophy and Uie Arts. mios.Jounuil .Vol. XXXIV. VIM. p. JOURNAL OF NATURAL PHILOSOPHY, CHEMISTRY, AND THE ARTS. FEBRUARY, 1813, ARTICLE I. An Account of some Experiments on different Comlinations of Fluoric Acid. By John Davy, Esq. From the Philosophical Transactions, 1812. Introduction, TWO years ago, I engaged, at the request of my brother, Statement of Sir H. Davy, in an inquiry respecting the nature of com-4 e su jec ' mon fluoric acid gas. My principal object was to ascertain whethersilex is essential to its constitution, and whether the pro- portion is constantly the same. This subject, and experiments on the fluoric and fluoboracic acids, occupied me for about six months. Since that time, the work of MM. Gay Lussac and Thenard has appeared, entitled " Recherches Physico-Chimi- qnes," in the second volume of which is an elaborate disserta- tion on fluoric acid. These philosophers, I find, have anticipa- ted many of my results, and consequently very much abridged my labour of detail in the following pages. To repeat what is already known would be useless j I shall therefore confine myself to describe what I have observed, which appears to me yet novel, or different from the observations of the French chemists. The order which I shall pursue, will be that which I observed in my experiments. I shall divide what I have to advance into Wen,. XXXIV,— No. 15/, G four g2 - TLUORIC ACID. four parts. The first part will relate to the silicated fluoric acid gas, and to the subsilicated fluoric acid -f the second to the combinations of these acids, and of pure fluoric acid with am- monia j the third to fluoboracic acid j and the fourth to its ammoniacal salts. Sect. 1. On silicated fluoric acid Gas, and subsilicated fluoric Acid. Fluoric acid The facts which have already been published by MM. Gay gat requires Lussac and Thenard and others, appear to me to be sufficient either silex oi* . _ ... , . t . . . boracic acid to to Prove that pure fluoric acid has not yet been obtained in admit of that the gaseous state, and that silex, or boracic acid, is requisite that it may assume this form. Were more evidences neces- Common fl. a. sary. j could advance many in point. One circumstance only £, is saturated. * . ' r . * I shall mention, proving that common fluoric acid gas is per- fectly saturated with silex. I have preserved this gas, made by heating, in a glass retort, a mixture of fluor spar and sul- phuric acid, for several weeks over mercury in a glass receiver uncoated with wax, without observing the slightest erosion t« be produced.* It is best obtain- This gas, with great propriety, has lately been called silicated ed by heating flaorjc .Before I proceed to its analysis, I shall notice what fluor spar, * * ' finely powder- method I have found the best tor obtaining it. I have, for ed glass, and a consjdCrable time, long before MM. Gay Lussac and together. Thenard's work was published, added to the mixture of fluor spar and sulphuric acid, a quantity of finely pounded glass, and have thus procm^d the gas with the greatest facility. The advantages of this addition are considerable. The retort is saved,, which otherwise, in less than one operation, would be destroyed j and a much larger quantity of gas is procured from the same materials, and with less trouble and less heat ; the action indeed at first is so powerful, that gas begins to come over before the application of heat is made, and a very gentle one only is required to continue its production. * The sides of the receiver indeed became obscure ; but this was not from erosion, but from deposition, as appeared Crom the transparency and polish of the glass being readily restored by slight friction. What the deposition was, I am ignorant of. After several weeks it was so Rifling, as to give only a slight degree of opacity to the receiver. Previous FLUORIC ACID. 83 Previous to its analysis, it was necessary to ascertain the Common Cor specific gravity of the gas. This I have endeavoured to do. s^f^ t-^cs The gas, the subject of experiment, was quite pure, being total- heavier than ly condensed by water. A Florence flask was exhausted ; jQ water- this state, weighed by a very delicate balance, it was = 1452*2 grains. Filled with common air - = 1452*2 -"- 10*2 Again exhausted = 1452*2 Filled with silicated fluoric gas = 1452-2 +36*45 Hence as 10*2 : 31 : : 36*45 : : 110 78 Thus it appears, that 100 cubic inches of silicated fluoric acid gas, at ordinary temperature and pressure, are equal to 1 10*78 grains. When silicated fluoric acid gas is condensed by water, it is .Bv pwcipitat- °w. ing thesilexby well known that part only of the silex is deposited. To ob- water and tain the whole, in order to ascertain the proportion in the gas, amon*a, the ti 11 •• ^^L--i/-i gas was found I have employed ammonia in excess. 40 cubic inches of the to contain 5 gas (barom. 30, therm. 60) were transferred in portions of Pa,;t3 acid and 10 cubic inches at a time to a solution of ammonia. The silex precipitated was carefully collected on a filter, and washed till the water that passed through it, ceased to be affected by nitrate of lime. It was next dried, and strongly heated in a platioa crucible. It weighed 27'2 grains, and was pure silex. Supposing fluoric acid to be the remaining 171 grains, which adde*d to 27*2 giains are equivalent to the weight of 40 cubic inches of the gas, it appears that 100 parts by weight of this gas consist of 6l*4 silex 38*6 fluoric acid 1000 That this estimate may be correct, it is evident* that am- monia should have the property of precipitating the whole of the silex of silicated fluoric gas j which I shall not now en- deavour to prove, but leave it to be considered in another part of the paper. There is no improbability attached to the idea, that silicated The gas con« fluoric acid gas may, from the manner in which it is prepared, 2££ D°- contain a proportion of alkali. To discover whether this was G 2 the 84 FLUORIC ACID. the-case, a solution of nitrate of lime was added to the ammo* niacal solution neutralized by nitric acid, from which the silex in the preceding experiment had been removed. The preci- pitate of fluat of lime was separated by filtration. The filtered ^liquid was evaporated to dryness j and the ammoniacal salt heated in a platim crucible till it was entirely dissipated. The residue had the appearance and taste of quick lime. It was dissolved in acetic acid, and the solution yielded sulphat of lime on the addition of sulphat of ammonia. The liquid was evaporated to dryness, and when the residuum has been heated to dull redness, nothing remained but a little white powder, weighing about a grain, and having all the properties of gypsum. Thus it appears that silicated fluoric acid gas contains no alkali. Common My next object was to ascertain the composition of common acij liquid fluoric acid— -that acid obtained by the decomposition of silicated fluoric acid gas by water, and which, on account of the separation that occurs of part of the silex, may, with ar subsilicat- greater propriety, be called subsilicated fluoric acid. For this ed fluoric acid. purpose^ 4321 cubic inches, barom. 304, therm. 50, or 44 cubic inches at common temperature and pressure, were suc- cessively added, two cubic inches at a time, to one cubic inch of distilled water in a small jar over mercury. The whole of this, the gas being pure, was readily condensed. The tem- perature was somewhat raised. The silex precipitated, formed a gelatinous mass of a blueish colour, which had absorbed all the water like a sponge, so that none appeared fluid. This gelatinous mass was carefully transferred to a filter, and washed with distilled water till it was rendered insipid and inca- pable of reddening litmus paper. It retained its blueish hue has lost more on^ wn,^st mo*st« When dried and ignited, it was in thin than one fourth lamellae, and of a snow-white colour, and surprisingly bulky. It of its silex by we;ghe(j 7*33 grains, and was found to be pure silex. Thus it uniting with ° ' 6 l water. appears that the subsilicated fluoric acid formed by the decom- position of 44 cubic inches of silicated fluoric acid gas contains 7'33 grains of silex less than the gas itself. Consequently, independent of water, which no doubt is essential to this acid, 100 parts of it seem to consist of 54*56 silex FLUORIC ACID, 85 54'56 silex 45*44 acid 10000 I have endeavoured to ascertain what quantity of silicated Water con- fluoric acid gas a given quantity of water will condense. In timeg it8 bullt one instance -J^ of a cubic inch of distilled water absorbed 51 of sil. fl. a. cubic inches, barom. 30*5, therm. 60. The gas was added to gas; the water in a jar over mercury, as fast as it was absorbed. The experiment was stopped, when the gas, after having re- mained in contact with the water a whole night, ceased to be diminished. According to this result, the proper correction being made for the additional pressure, water decomposes about 263 times its bulk of silicated fluoric acid gas. Dr. Priestley observed, that muriatic acid gas re-produced silicated fluoric gas from the crust of silex formed, when the . latter is condensed by water*. This experiment I have re- peated, and as it appears to show more correctly the quantity of gas water can condense, I shall describe the result. 2*4 cubic inches of muriatic gas were added to a drop of water, that had previously absorbed one cubic inch of silicated fluoric gas, in a jar over mercury. There was an immediate absorp- tion equal to T20- of a cubic inch. The mixture of silex and subsilicated fluoric acid effervesced, and from an apparent solid became fluid, the whole of the silex gradually disappear- ing. After the first mentioned absorption, there was no far- ther. The gas produced was silicated, as appeared from the crust it deposited when removed to water, and the liquid formed was pure muriatic acid, for decomposed by concentrated sulphuric, it afforded merely muriatic acid gas, without any sili- cated fluoric. The evident conclusion from the preceding result is, that water condenses equal quantities of the muriatic and silicated fluoric acid gases, and consequently that the first or more cor. estimate is too low, and instead of 263 times its bulk, it is r.ectIy 365 probably more correct to say that water to be saturated re- quires at least 365 times its volume. Neither will this estimate appear inconsistent with the former results, when the deposi- * Vide Priestley on Air, Vol. II. p. 202, lion 86 FLUORIC ACID. Subsilicatedfiu- oric acid|is de- composed by alkalies, and by earths and acids. Habitudes of subsilicated flu oric acid with heat. It came over in distil- lation; &c. This differs from Doctor Priestley's re- suit. Fluoric acid gas cannot be had by di filia- tion free from silex. tion of silex is considered as an obstacle to the free exposure of the surface of the water to the gas. Subsilicated fluoric acid is decomposed by ammonia and the fixed alkalies, and by all the earths that I have made trial of. It is also decomposed by the sulphuric acid and the boracic, as well as by the muriatic acid gas. Of the particular changes which occur when it is acted upon by the alkalies, I defer giving any account at present, as it is my intention to do it in the next section. To learn the effect of heat on it, a small quantity of strong acid, pure and transparent, was introduced into a retort con- nected with mercury. A spirit lamp being applied, about three cubic inches of silicated fluoric acid gas were produced. The neck of the retort was lined with silex in a gelatinous state, and much liquid subsilicated fluoric acid, that had distilled over, was condensed in the colder part of the neck, and was absorbed by bibulous paper previously introduced, to prevent the distilled fluid from entering the jar for the reception of the gas. When the whole of the acid in the bulb of the retort had been evaporated, little or no silex remained. The general result of this experiment is very different from that which Dr. Priestley, who first made it, obtained. Instead of silicated fluoric acid gas, he procured " vitriolic acid air," sulphureous acid gas. I have tried also the effect of heat on the silicious crust, formed by the decomposition of silicated fluoric acid gas, by water j but could obtain no sulphureous acid gas, as Dr. Priest- ley did only a small quantity of silicated fluoric. The correctness of Dr. Priestley's observations cannot be doubted. I can only account for his results, by supposing that some sulphuric acid in consequence of the high temperature employed in making the gas was volatilized, and mixed with the subsilicated fluoric acid, and that mercury also was present, from the acid being prepared over this metal. These experiments too oppose another statement relative to a method prescribed for making fluoric acid gas free from silex, by merely heating strong subsilicated fluoric acid in a retort, and collecting the gas over mercury. It is asserted, in chemical works of some reputation, that this process is suc- cessful. I have never found it so, having always obtained results "FLUORIC ACID. '&J results similar to those above stated. This, I suppose, is one of the many errors that have secretly crept into repute, and has been believed, because never subjected to the test of experi- ment. The action of concentrated sulphuric acid on subsilicated Sulph. acid ex- a .,..., , _ . . . . . pels silicated fluoric acid, is similar to that of muriatic acid gas, occasioning flUOricacidga» a disengagement of silicated fluoric acid gas. Facts which from subsili- ippear to prove, that water is absolutely essential to the exist- acirj# ence of this acid. Boracic acid decomposes it, in a very different way, not from Boracic acid any predominant affinity for the water, but in consequence of J!n,te.s Wltj \ the a stronger attraction for the fluoric acid itself. Silicated fluoric and both acids acid of course is not produced : but liquid fluoboracic acid and ar,e precipitat- . ... J ^ ed along with the silex is precipitated in a gelatinous state, as when ammonia thesilex. is employed. These are the principal facts I have to notice respecting this Subsilicated acid. Before I conclude, I shall briefly mention a few other act3 oll the circumstances. Applied to the tongue, in its concentrated state, tongue, and it produces a very painful sensation, like that which str°ng P""01"0 muriatic acid does, and it has a very similar effect on the cuticle. It does not appear to erode glass, for I have kept it in bottles of this substance more than a month without any action being perceptible. Exposed to the air, it slowly and almost completely evaporates, there being only a very trifling silicious residue ; and when gently heated in an open vessel, it is rapidly dissipated in white fumes. Sect. ii. On the Combinations of silicated fluoric acid Gas, and the subsilicated Fluoric, and the fluoric Acids with Ammonia. M. Gay Lassac has shewn that silicated fluoric acid gas, Silicated fluo- like carbonic acid gas, condenses twice its volume of the vola- condenses tile alkali.* The experiment I have several times repeated, twice its vo- and constantly with the same result, no difference appearing o^thfrd^nti when the acid gas was added in great excess to the alkaline, weight of am- or the alkafne to the acid. This being the case, and knowing monu« the specific gravity of the two gases,f 100 parts by weight of silicated fluat of ammonia seem to consist of * Vide Mem. d'Arcueil, Tom. II. f According to Sir H.Davy, 100 cubic inches of ammonia, barom. 30, therm. 60, weigh 18 grains. It is thil estimate which I have taken. 24' $ gg FLUORIC ACID. 24 '5 ammonia 7 5' 5 acid 100-0 Silicated fluat of ammonia volatilizes unaltered, if heated by a spirit-lamp in the vessel in which it is formed, and provided * moisture be entirely excluded. Water decom- Ljfce silicated fluoric acid gas itself, this salt is decomposed by pound and " water, and a similar precipitation of silex occurs, and in tho precipitates same proportion. Thus the salt formed by the union of 30 cubic inches of silicated fluoric gas, and 60 of volatile alkali (barom 30, therm. 60) in a small glass jar over mercury, being carefully collected and introduced into water, afforded five grains of pure silex, weighed after being well washed and heated to redness. The aqueous The saline solution, since part of the silex of the silicated Skated fluat " ^uo"c acic* &as IS seParated during its production, appears to of silex and be a subsilicated fluat, or a combination of subsilicated fluoric oma* acid and ammonia. Another mode of making it, more directly proves that this is its composition. When ammonia is added to the subsilicated fluoric acid in excess, this salt is formed with- out any precipitation. From these facts, it may be concluded, that independent of water, which appears to be essential to its existence, 100 parts of it consist of 28*34 ammonia 71-66 acid 100-00 It has a pun- Subsilicated fluat of ammonia has a pungent saline taste. It ?eddensSlitmus;Just perceptibly reddens litmus paper. Slowly evaporated, it crystallizes not forms small transparent and brilliant crystals. The largest I cor^e^glass could obtain» appeared to be tetrahedral prisms. The solid salt whilehot,&c. is very soluble in water j but is not deliquescent. When heated it appears to sublime unaltered. It is curious that the solution of this salt, when evaporated by a heat near its boiling point, powerfully erodes the glass or porcelain vessel, and a residuum of silex appears, on the addition of water, to re-dissolve the salt. This erosion and residue of silex I have seen produced three times following, with the same quantity of salt. I mention the fact, FLUORIC ACID, 8$ fact, which, I believe, was before observed by Scheele, without attempting an explanation of it. It may, perhaps be said, that as the water evaporates, the affinity of the subsilicated fluat for «ilex increases. Subsilicated fluat of ammonia is decomposed by the sulphuric I* decomposed acid, and by muriatic acid gas, and also by the fixed alkalies aJd"andatka- and by ammonia. lies. Sulphuric acid expels from it, silicated fluoric gas and hy- Effects of sul- drated fluoric acid fumes. ■**# acid' Muriatic acid gas acts slowly on it, and effects its decomposi- and muriatic tion apparently through the medium of its water. A little aci ga8* of the crystalline salt was introduced into muriatic acid gas in a jar over mercury. In a short time, some silicated gas was produced, as the silicious deposition, on the addition of water, indicated. Strong muriatic acid was substituted for the acid gas. Now no apparent change took place, for on evaporating M«k{jtic idii the acid, the residue, decomposed by sulphuric acid, afforded no change : only silicated flucric acid gas. The alkahes form by the decomposition of this salt, the same Alkalies form- compounds that they do by their action on subsilicated fluoric tne same salts as with the ■acid. _ subsilicated Potash expels the ammonia, and produces the silicated fluat aci«l. and fluat of potash, as MM. Gay Lussac and Thenard have described . The changes occasioned by soda appeared to me similar : but the gentlemen just mentioned, assert that this alkali preci- pitates the whole of the silex, and does not form a triple salt with it and part of the acid. Ammonia seems to me to separate completely the silex, and Ammonia by uniting with the pure acid to constitute a true fluat. MM. completely •* Gay Lussac and Thenard are of a different opinion. They jex, say that the whole of the silex cannot by this method be re- moved, but only the principal part. Their reason for this belief, is, that on repeatedly evaporating the salt after the addi- tion of ammonia and re-dissolving it, they have each time ob- served a residue of silex. If they employed metallic evaporating vessels, the results of my experiments do not agree with theirs ; for making use of platina for this purpose, and adding an ex- cess of ammonia, I never detected traces of silex on evaporating the filtered fluat. But our results agree, if they employed glass or X)0 FIGURE Or THE EARTH.' or porcelain vessels, which fluat of ammonia has the property of corroding. (To be Continued) II. Observations on the Measurement of three Degrees of the Meridian conducted in England by Lieut. Col. liyilliam Mudge, By Don Joseph Rodriguez. From the Philoso- phical Transactions for 1812. p. 321. (Concludedfrom p. 334, Vol. XXXIII.) The uncertain- But to return to our subject of the English measurement. ty which may jf the uncertainty which yet subsists, with respect to the exact subsist respect- ,, ~ . !■_».».. • m ing the figure, "gure ot the earth and its dimensions, occasions some small &c of the errors in the calculation of the series of triangles, the sum of affect'the entire tnese eriors WM be found in the estimate of the entire arch, arc propor- and will increase in proportion to the extent of the arc mea- thsm any^art sure(^* Now, in the English measurement, we find exactly of the same; the reverse of this. For the difference between the results of trarv ^annens calculation and observation is only l",38 on the whole arc j in the English but is even as high as 4",77 on one or* tne smaller arcs. So measurement : tjia^ whatever error we may suppose to have been introduced into the calculation, by assuming a false estimate of the sphe- . roidity of the earth, or of other elements employed in the ■which shews ..... . , , , . . .. - a considerable calculation, it is very evident that the zenith distances ot stars error of ano- taken at Arbury Hill are affected by some considerable error, theobs. wholly independent of these elements. It was not till the date of the measurement of the meridian in France, that M. Delambre published and explained, with admirable perspicuity and elegance, all the formulae and me- thods relative to the calculation of spheroids, and put it in the power of astronomers in general to make use of the elliptic elements in verifying the results of their observations. In the present state of science these elements are well known, and .,,, the errors that can arise from any uncertainty in them, are I he errors y / from uncer- not so considerable as is generally supposed. The oblateness tai.nty mthe and the diameter at the equator are the only elements want- elliptic ele- . ,,. / i r ■ , ^ mcnts are not ing in the calculation 3 for the purpose of seeing what effect «on*iderabIe. our Fkilos.fmri.r.MD(YX/l.Pl./.p..}70 AVi i J 3 . & ^-^r 4 5 0 1 8 S 10 Tl 12 13 14 IS 16 11 U 19 20 21 la. J. 10' Common Camera obscura Fiq.4. Feriscopie microscope Teriscopie Camera obscura If.i'.vpfT jeulp. FIOUBE OF THE EARTH. Ql our present uncertainty respecting them can have on the sub- ject in question, I have employed three different estimates of the oblateness -£fa yffc , and y^. With respect to the radius of the equator, that is ascertained with sufficient precision by the mean of the arc extended from Greenwich to Formen- tera, corresponding to latitude 45 418". The value of the degree in toises is 5/010,5, and it is highly probable that in this estimate the error does not amount to so much as half a toise, as it is deduced from an entire arc of 12° 48' between the two extremities, the latitudes of which have been deter- mined with extreme care, and by a great number of obser- vations. The following are the logarithms of radius at the equator By assuming ,.,x, , , f , ii r^i *hree different which I have employed as adapted to each degree or oblateness, estimates of and opposite to them are placed the corresponding computed oblateness the estimate of the entire arc between Clifton and Dunnose. t^e resuit, -r] 6,5147,400 2° 50^21,972 3-i 6,5147,485 2° 50' 21,974 tK- . . . 6,5147,570 2° 50' 21,976 so that the greatest difference is but 0",38> Let us suppose it 0',4, or evenO",5, for the second calculation was made only by means of the western series of triangles, and the third only was the eastern j but even then the error arising from uncer- tainty in the elements is not half the difference we find between the results of computation and of observations of the fixed stars. It appears, therefore, that these elements are by no means to be neglected as a method of verification ; and in fact the quantity of 1^,38 is so small, that it is extremely dif- /- , . .... , prove too ficultto ascertain this quantity with the very best instruments. small to be in Of this we shall find further proof hereafter j but as this dis- general ascer- cussion is not without its use, I shall enter into some, details on this subject. The measurement in Lapland was performed by means of The same a double metre, and with a repeating circle of Borda, sent by shewn from the National Institute of France. In order to see to what ob^^tions • degree of accuracy the arc computed would agree with that obtained by observations of the pole star above and below the pole, I assumed an oblateness of -g-i^- and as logarithm of adius I had 6,5147500 expressed in toises and in round num- bers. 95 FIGURE OF THE EARTH. b^rs. With these elements, and with the data to be found in the work of M. Svanberg, we have by the western series of v triangles 5840",196 and 5840", 138 by the eastern. So that the mean calculated arc is 1° 37' 20", 167, while the arc ob- served was 1° 37' 1$',56G. The difference then is 0',6 for the total arc, and 0',37 for the mean degree, or 5,86 toises excess in the linear extent. One can never depend upon quantities so small as this, so that the agreement between the results of computation and actual observation, proves not only the skill of the observers arid the accuracy of which their in- struments admit ; but also that the elliptic elements employed in the calculation are a sufficiently near approximation to the truth to be deserving of confidence, and also In the 8th volume of the Asiatic Researches, published by tures on the " ^e Society at Calcutta, are contained the details of another meridian taken measurement performed in 1802, by Major William Lamb^ Ma^or William. *onm Bengal, on the Coromandel coast. In this undertaking, Lambton; which was executed with great skill and attention, Major Lambton employed Bengal lights as signals, chains for the linear measures, and a theodolite, and a zenith-sector made by Ramsden. The base measured was 6667,740 fathoms reduced to the level of the sea, and to the temperature of 62° Fahren- heit ; and the stations were so chosen, that four of the sides of the triangles were almost in the same line, and nearly parallel to the meridian at the southern extremity of the arc, so that their sum but little exceeds its whole extent. The lengths of • these arcs in fathoms reduced to the meridian are thus given in the Memoir of Major Lambton. AB 20758,13 north latitude of A 1 1? 44' 52' ,59 BC 17481,245 CD 22237,04 north latitude of E 13° 19'4o/<,018 DE 35246,43 From these data Major Lambton deduces the degree of the meridian to be 60435 fathoms, or 56762,3 toises. By apply- ing to this the same elements as we did to the measurement by Svanberg, we have the entire arc measured equal to 1* 34' 55S896 j so that the difference between the results of cal- culation and of the observations is only 0'',532 for the whole arc, or 0'',337 for the mean degree. The elliptic hypothesis and observation agree more correctly in this instance, for the diffe- jence FIGURE OF THE EARTH. Q3 Tence is rather less than in that of Lapland, although the two arcs are very nearly of the same extent. Thus the de- gree on the meridian measured in Bengal, in the latitude of 12^ 32' 21' north, cannot be supposed to exceed Major Lamb- ton's estimate by more than 5,22 toises j and it is extremely difficult to speak with certainty to quantities so small as this. The same observer also measured one degree perpendicular and also to the meridian, by means of a large side of one of his triangles from a '-csrree . ,. , .7^ , , , ,;.D. measured by cutting the meridian nearly at right angles, and of which he Major Lamb- observed the azimuth at the two extremities. The data from ton» perpendi- which his results may be verified are these : meridian. Length of the chord of the long side in English feet AB= 291197,20. Azimuth of the eastern extremity A equal to 87° 0" 7",54: NW. Azimuth of the western extremity B equal to 267° 10' 44',07 NW. North latitude of A 12« 32' 12",27 North latitude of B 12° 34' 38",86. With these data in the triangle formed by the long,side, the meridian at B, and the perpendicular from B on the meridian at A, we have the chord of this last arc equal to 290845,8 feet, and the arc itself 290848,03 feet. By applying the me- thod of M. Delambre, we find the azimuth of the extremity B less by 2 " than it was observed to be ; so that we have no reason to suppose a greater error than one second in the obser- vation of each azimuth, and it seems next to impossible to arrive at a greater exactness. The difference of longitude between the points A and B is 48y 57",30. With this angle and the co-latitude a>t A, we hav« in the spherical triangle right angled at the point A, the extent of the normal arc equal to 2867,330 seconds, and dividing its length in feet by this number, we have for the degree per- pendicular to the meridian, at the extremity A, 60861,20 fathoms, or 57106,5 toises. Now these values are precisely what we find on the elliptic hypothesis, with an oblateness of TJRr or -j A-g. j and in short, the correspondence between the hypothesis and the measures of Major Lambton, is as complete as can be wished. Major Lambton, indeed, finds the degree on the 9± FIGURE OF THE EARTH. the perpendicular too great by 200 fathoms, but this arises from a mistake in his calculation. By applying Lastly; I shall apply the same method, and see how nearly thodaofeCom- tIie e,5iPllc hypothesis agrees with the last measures taken in puting the arcs France, which merit the highest degree of confidence, both in seconds and wjtn reSpect to the observers who have executed it, and the in toises, the ■ " i elliptic hypo means which they had it in their power to employ. I have to^'Vee w^rf taken only the arc between Dunkirk and the Pantheon at Paris, the fate mea- from the data published by the Chevalier Delambre in the sures taken in 3tj vol. of the Measurement of the Meridian. I employed the same elements and similar calculations to those made on the English arc. The oblateness of T^ gifes the difference between the parallels equal to 7383,615 seconds by the eastern series of triangles, and 7883,617 by the western series. The mean of these 7883,616 may be taken as the true extent of the total arc. The two other elements give for this quantity, 7883',62l and 7883",4p3, or 2° 1 1' 23",6 and 23",49, as the calculated extent of the arc. But the arc observed was 2e ll' ic>",83, according to M. Delambre, and 2° 1 1' 20",85 according to M. Mechain j so that the least difference between the cal- culation and the observations will be 2",64. M. Dehmbre is of opinion, that the latitude of Dunkirk, which is sup- posed to be 51° 2' 9",20, should be diminished; and in fact the distance between the parallels of Dunkirk and Green- wich, which is 25241,9 toises, gives by the mean of the three assumed elliptiticies 26" 32\3 for the difference of latitude. After deducting this quantity from 51° 28' 40'', the supposed latitude of Greenwich, there remains 51° 2' 7",7 or 8", for that of the tower at Dunkirk. If from this again we deduct the calculated arc 2Q ll' 23",5, we have 48° 50' 447,5 for the latitude of the Pantheon, while, according to the observations of M. Delambre, it is 49", 37, or 48",35 by those of M. Me- chain. If various circumstances, with regard to unfavourable weather, and also others of a different kind connected with the revolution, and of which M. Delambre complains with much reason, have occasioned some uncertainty with respect to the obser rations at Dunkirk, still the numerous observations made at Paris, both by him and by M. Mechain at a more favourable season, and in times of perfect tranquillity* render the supposition of an error of 4 seconds in the latitude of the Pantheon IIGURE OF THE EARTH. Q5 Pantheon wholly inadmissible. It is, however, too true, that such errors are possible, and it is only by careful perseverance, and by repeated verification, that they are to be discovered and removed, as we have seen to be highly probable with respect to the station at Arbury Hill. But the same celebrated observer, M. Mechain, who handled Jnstance ?J . * ' irregularity m instruments with great delicacy, and was possessed of peculiar observing the talents for this species of observation, has given us an instance n New could also be undertaken, either in New Holland, or in Brazil j ° an ' for though neither of these countries differs much in latitude from the Cape of Good Hope, they are so remote in longitude, that a correspondence of measures so taken would nearly esta- blish the similarity of all meridians. Note. I shall now explain the formulae employed in deducing the Formulae em- results to which I have come in the foregoing Memoir. The P'°yed in the demonstration of them is to be found in the work of M. De- computation, lambre, on the Meridian. In the first place, let a be the radius of the equator, e the ec- centricity, >]• the latitude of one extremity of a side, or arc, iri any series of triangles, and 0 the azimuth of that side. The radius of curvature of this arc will be expressed by (1 -| • cos. ty . cos. 20 } 1 — e» J 1— «* J , 1 (1— e"-. sin. *^)i = and — = . Rl R R a Hence we see that R is the radius of the arc at right angles to the meridian. One may in general neglect the azimuth, and take the last radius for the radius Rl. Now, in compu- ting the arc between Clifton and Dunnose, I have supposed the oblateness to be — ore2 = — 2> and log. a = 0,5147200 expressed in toises. The latitude of the southern extremity of the base is the same as that of Clifton, and its azimuth, if we choose to attend to it, is nearly 335° 23'. This base, considered as an arc of a K. i» circle, is reduced to its sine by the formula 8 = log. « — 6R» ' Vol.XXXIV.—No. 157. H (K 98 FIGURE OF TftE EARTH. Formula em- (K being the modules of the table of logarithms, so that log. plovedinthe K = Q,6377843.) preceding computation. By means of the logarithmic sine of the base, and the angles of the triangles, considered as spherical, the logarnhmic sines of the sides in the series were next computed, and then reduced to logarithms of the arcs themselves by the formula i i . K sin. U log. « = log. sin. s H gg — For the purpose of making this las! reduction, it is sufficient to take a single value of R, corresponding to the mean latitude of the entire arc 52 2' 20". It was thus that the table was formed of logarithmic sides considered as arcs. Let 7/2 be one of these arcs, and let us represent by ^ arsci o\J/' its value reduced to the meridian, the one in toises, the other in seconds of a degree, and we shall have the following formulae ; *-«•«*•- (— 5K— ) -tang .+_(-__ ) . (— R-) . (1+3 tan. ^) ty '= L, **':,) + f.yt|J . e« . (1 + e2) . cos. 24- . 5 1 + VR • sin. i / ' \R. sin, 1 / v r C (3ta",.T\ . (~) i : the superior sign being taken when the latitude ■]," is greater than ^, and the inferior when it is less. The correction dependent on the convergence of the meri- dian for the azimuths is £0 = (p ,' *■'"' ,„) . ( J" ,', ' II /l V VR1. sin. 1"/ vcos.'4/ . cos. £ ©y"/ Hence the azimuth of the first station seen from the second and reckoned westward from the north, is fi' = 180' + 9 + Jfl. IfP" be put for the difference of longitude between two points distant by an arc which measures m, we have sin. P sin. m . sin. 0 , . . /w\ K/mX(> , = -st-'1o§'81"'8,=1"8' vr.' — t • W) • and The arc of the meridian, between Greenwich and For- mentera, is so fortunately situated, that its middle point is in latitude 45°. Its whole extent measures 12° 48' 44", and the distance between the parallels, in linear measure, was found to be 730430,7 toises. Hence the mean degree, corresponding to the latitude of 45° 4' 18', is 57010,5 toises j and if we multi- ply FIGURE OF THE EARTH. 99 ply this number by QO'1, we get one-fourth part of the meridian Formulae em- Vi , ployed in the of the earth. preceding The correction to be deduce! for oblateness is 58, 59, or computation. 61 toises, according as it re assumed to be j-V~, — V-» or -y-j-o-, and if we take the mean of these, we have the fourth part of the meridian Q= 5130886 tdises ; and hence the metre =a 4433080/ lines j so that the value of the metre turns out to be almost entirely independent of the ellipticil form of the earth. The radius of the equator is derived from the expression log. a = log. (2^-) + K . (I . « f TV . *2- ^.s3), e being the oblateness, and ?r the periphery of a circle = 3, 141 6. In order to compare any degrees measured with those ob-e tained on the elliptic hypothesis, we have, a very simple for-* mula. Let m and m. be the values of two degrees on .the. meridian, of which the mean latitudes are .4,1 and -4-2 ; in com- paring the analytic expressions for these two degrees deve- loping them, and then making ^ = 45°, we have rri = m . (1— i . p . cos. 2^2+g . cos. 22l2), m a? 5/010,5 toises, p — i * r, {, Hv . ^j° . and >gw%r- side towards the incident parallel rays, has less aberration than any meniscus with its < > side exposed to parallel rays. Whence (concave > ? r j it necessarily follows, that that meniscus is best, which ap- proaches ncaiest in shape to a plano-convex lens." Harris (of the Mint) Optics, 1 77(5, p. 67. So sensible have some optical glass grinders been of the im- practicability and insufficiency of the meniscus glasses of short foci for spectacles, that I have in my possession some plano- convex and plano-concave glasses actually fitted in the frames, and sold for the neiv periscopic glasses. Observations The sort of French angle of reduction that Dr W. has given, ©n the peris- to obtain geometrically but nearly the radii of meniscus for a given focus, will be useless to the workman, as he aheady knows, by a very short arithmetical operation, how to obtain exactly such radii in half a minute's time, or a tenth part of the time necessary to construct that problem by Gunter's sliding rule, the time would be still shorter. The combination of using two glasses in ordinary simple microscopes, or hand magnifiers, to diminish the errors arising from the spherical figure of one glass, was known to Sir Isaac Newton, and successive opticians. That late excellent practical optician, Mr. Ramsden, by the combination in the best position of two piano glasses, with their convex sides to each other, ap- plied eye-pieces to his instruments with great advantage, to read off divisions of his circles, and magnify the wires ot his teles- copes, with clear definition at the circumference of the field of view, the diameters of the glasses being no smaller than the aperture of the tube. The same principle has since been advan- tageously applied to large object lenses for the lucernal micro- scope, «or.ic micro- scope RULES FOR INVENTION. 107 scope, by the late Mr. G. Adams, and ourselves, where the diminution of light was of less consequence than indistinctness of the image In many cases the combination of two convex lenses answer very well : but the combining of-two similar plano- convex lenses together, of superfluous diameter and thickness, and for the greatest defect or aberration in the worst position to each other; and afterwards to palliate it with a small aperture as shewn in figure 4, is such an anomaly or absurdity in opitics as not to require any serious comment on my part. I shall only appeal to the least experienced constructor of microscopes, whether he does not know, that the substitution of a double convex lens of the diameter only of Dr W.'s aperture, and of the s:ime focus, would produce an image infinitely more perfect and vivid than the mutilated one proposed by Dr. W. From these remarks I presume there will be nothing to apprehend from the attempt of Dr. W. to depreciate the excellence of the spectacles, Camera Obsuras, and Mocro- scopes, as have been constructed by the most eminent Opticians of the day. I am, Sir, » Your's, &c. W. JONES. Holborn, \6thJan. 1813. IV. Rules for discovering new Improvements, exemplified in the art of thrashing and cleaning grain ; hulling rice ; warming rooms ; preventing ships from sinking, &c. By Oliver Evans, of Philadelphia*. NECESSITY is called the mother of inventions j but upon origin of In. inquiry we shall find thatreason and experiment bring them ventions. forth j for almost all inventions have been discovered by such steps as the following -> which may be taken as a * From the Appendix to his" Young Mi!l-wright and Miller's Guide" printed by subscription in Philadelphia, but very sarce in this country. J 08 RULES FOR INVENTION, Rule for in- venting I. Consider the theory and present prac- tice of art. II. and what in speculation ■would be the best plan of operating : III. how far and in what respects the present prac- tice can be improved : IV. make ex- periments or Trials of the plans thus 4 educed from reasoning. Example. I. Tin ashing of grain. I. Pi inciples of the nrt. To disengage the grain : by beating or by rubbing. II. Theory apply force to the heads only. HI. Present practice. Thrashing by men : treading by animal*. Disadvantages. I. The force is employed on the straw as Rule Step 1. Is to investigate the fundamental principles of the theory, and the process of the art or manufacture we wish to improve. II. To consider what is the best plan in theory that can be deduced from, or founded on, these principles, to produce the effect we desire. III. Consider whether the theory is already put in practice to the best advantage, and what are the imperfections or dis- advantages of the common process of the art, and whether they can be evaded and the process improved 3 and wh3t plans are most likely to succeed. IV. Make experiments in practice to try any plans that the speculative reasonings may propose or lead to. Any ingenious artist, taking the foregoing steps, will probably be led to im- provement in his own art ; for we see by daily experience that every art may be improved. It will, however, be in vain to attempt improvements, unless the mind be freed from prejudice in favour of established plans. Example 1. Suppose we take the art of thrashing grain. Then by the rule. -Step 1. What are the principles on which this art is founded ? The grain is contained in a head on the top of the straw enclosed in a husk, or chaff, that requires a force to break the hull, and disengage it j which may be done either on the principle of beating or of rubbing. II. What is the best plan in theory for effecting this? As we find that it requires nearly equal force, and is all contained in the head, which is much less in quantity than the straw, theory directs the force to be regularly and uniformly applied to the head only, which will require but little power, seeing we can rub it out between our hands. III. How is this theory put in practice; and what are the imperfections and disadvantages of the common process ? the grain in the straw is laid on a plank floor, and beaten by men, with flails ; or on the ground, and trod out by horses. The disadvantages are. 1st. The force is in both cases applied equally to the straw, as well as the head. BULfeS TOR INVENTION. J QQ II. Much force is lost, being unnecessarily expended in well as the beating the straw, yet many heads escape undone, because fj*ce;i08't#an the force is so irregularly applied. III. In treading by horses the grain as well as the straw m. Cattle gets dirty make grain IV. Thrashing by men is both expensive and tedious. ' Now cannot improvements be made to overcome all these Thrashing is disadvantages ? Such speculations have produced several. expensive and First, a machine on the principles of a coffee mill, which __ ' . r r Machines al- requires very Jittle force to rub the grain out of the beads, ready made. which are separated from the straw, by means of a machine on va) A mill to , .... . rr- ~~, . ri,h tIie grai& the principle ot a comb, cutting them oft. A machine to reap from the the heads without the straw is wanted to complete this theory, heads, (in countries where the straw itself is not an article of demand). Secondly, a machine invented and put in practice by Colonel (b) Revolving Cylinder with Alexander Anderson, of Philadelphia j the principles of which beaters on its are to apply the strength of horses to strike the straw regularly circumference, with a uniform force* which finishes as it goes and clears the use as deeP as possible. Tlien dies from the the lightest will be carried farthest and the separation be more gram by a complete at the end of the fall. Secondly, cause tliegrainj current of air ; r }> to deep; but not with the chaff, &c. to fall in a narrow line across the current, wide, across that the light parts may meet no obstruction from the heavy Let the grain 'n being carried forward. Thirdly, fix a moveable board &c fall iuto edgeways to separate between the good clean grain and light compartments . « . . , , ,, 7, . and use the gram &c. Fourthly cause the same blast to blow the grain same blast re- several times, and thereby effect a complete separation at one peatedly. r * operation. tice^Th"0' ll1' Is th5s iheovy m Practice already, and what are the dig- grain does not advantages of the common process ? We find that the common fall through a farmers' fans drop the grain in a line 15 inches wide, to fall suitable r ° cavity; nor is through a current of air about 8 inches deep, (instead of falling itcleanec at \n a j-,ne x an jnch wide through a current 3 feet deep) so that one operation. . . * . . , , , , «. , it requires a very strong blast even to blow out the chair j but garlic, light grains, &c. cannot be got out, they meet with so much obstruction from the heavy grain. It has to undergo 2 or. 3 operations ; so that the practice is found to be no way equal to the theory j and appears absurd when tried by the scale of reason. Plan of im- IV. The fourth step is to construct a fan to put the theory in provements. pra(:lice^ t0 try lhe experiment*. Exp. m. Art Example III. The art of warming rooms by fire. of ic rminsr o -r r™ • i c r .. • u ■ ntm,hts. S.ep I. lhe principles of fire are too mysterious to be m- Nature of fire vestigated here j but the effects are, Effect**?1?/ ' lst* ^iie ^ire rare^es Vne air in {^° loom, which gives the rarefies the air. sensation of heat or warmth. II. Causes part II. The warmest part being lightest, rises to the uppermost toascemi; part Qf ^Q room> nuc\ w\\\ ascend through holes, (if there be any) into the room above, making it warmer than the one in which the fire is. Iff. particu- III. If the chimney be warm, the air will fly up it n>st, chimney/0 leaving the room empty. The cold air will then rush in at all which pro- crevices to supply its place which keeps the room cold. * This Machinery, with a large passage or channel, is useful to clean feathers from dirt and heavy bodies. — W. N. RULES FOR INVENTION. Ill II. Considering the principles, what is the best plan in theory *Jg* »** for warming a room ? . Practical re- I. We must contrive the fire to spend all its heat to warm J*W. 1 I. Employ the the air as it comes in the room. whole heat ia II. To retain the warm air in the rooms, and let the warming the ... a!r- coldest out first to obtain a ventilation. U prevent it» IH. Make the fire in a lower ruom, conducting the heat escape, and „ ii- .l i i ventilate by- through the fl x>r into the upper one, and leaving another hole escape o[ ^ld for the cold air to descend to the lower room. air. IV. Make the room perfectly tight so as to admit no cold and vem-™te air, but all warmed as it comes in. several apart- V. By stopping up the chimney to let no warm air escape up "yn[,seat the it, but what is absolutely necessary to kindle the fire, a hole of air as it come* two square inches will be <»utf:,cient for a very large room. y 'i imit the VI. The fire may be kindled by a current of air brought aperture of the from without, not using any of the air already warmed. If this Sjt1™,11^ the theory, which is founded on true principles and reason, be com- combustion pared with common practice, the errors will appear the dis- w,.l|1 a,r iroax r r ■ k without, advantages of which may be evaded. Experiment III. I had a stove constructed to put the theory as fully in or trial, practice as possible, and have found all to answer according to theory. A stcve de- The operations and effects are as follows, viz, scribed m ge- ,. ^ ... , icral terms. I. It applies the fire to warm the air as it enters the room, and admits a full and fresh supply, rendering the room mode- rately warm throughout. II. It effectually prevents the cold air from pressing in at the chinks or crevices, but causes a small current to pass out- wards. III. It conveys the cold air out of the room first : — conse- quently, IV. It is a complete ventilator rendering the room healthy. V. The fire may be supplied in very cold weather by a Current of air from without, that does not communicate with the warm air in the room. VI. Warm air may be retained in the room any length of time at pleasure ; circulating through the stove, the coldest entering first to be warmed over again. 112 HULES FOR INVENTION. VII. It will bake, roast, and boil, equally well with the common tin-plate stove, as it has a capacious oven. VIII. In consequence of these philosophical improvements it requires not more than half the usual quantify of fuel*. Ex. 4 Art of Example IV. The art of hulling and cleaning rice. hulling nee. r o & Pri//W/ 1st. To cast overboard such things as will not float, and care- Throw the fully to reserve every thing that will float, for by them tte ship oveJboard^8 may at last be buoyed up. 2nd. Empty every cask or thing that can be made water Empty the tight, and put them in the hold, and fasten them down under casks, and water, filling the vacancies between them with billets of wood, Up"gt emw*u even the spars and mast may be cut up for this purpose in des- perate cases, which will fill the hold with air and light matter, and as soon as the water inside is level with that outside, no more will enter : if every hogshead buoy up 875lbs. they will be a great help to sustain the ship, (but care must be taken not to put the empty casks too low, which would overset the ship) and she will float, although half her bottom be torn off. Mari- sj,;ps are safer hers for want of this knowledge often" leave their ships too soon, than boats. Taking to their boat, although the ship is much the safest, and does not sink for a long time after being abandoned ; not con- sidering, although the water gain on their pumps at first, they may be able to hold away with it, when arisen to a certain easily worked height in the hold ; because the velocity with which it will in a water- enter, will be in proportion to the square root of the difference ^fch may** between the level of water inside and out j added to this, the therefore, be fuller the ship, the easier the pumps will work j therefore, i*"^ pt a* they ought not to be so soon discouraged. V. Us if ul or Instructive Notions, respecting various objects. X.MuU . tiplying of Copies of Writing. 2. Scintillation of the Stars, 3. Large Achromatic Lenses. — W. N. 1 . Art of Copying, or of multiplying Copies. EVERY one is aware of the invaluable benefits which society has derived from the arts of printing, by moveable types, as well as by blocks and copper plates. But there are many cases, Benefits of the in which it would be of advantage to produce copies of writing, art oi prUt- without requiring a stock of types or engraved plates j and the1 ** presses, or implements, by which the impression is made. A Vol. XXXIV.— No. 15;. I wving, iI4 USEFUL NOTICES. saving, either in machinery, labour, or skill, is much to be desired. Under the present head, I have a few observations and facts to offer, relative to manuscript writing. The cele- brate James Watt, about thirty years ago, obtained a patent for a copying machine, for making copies of the description, James Watt's known by the name of counterproofs. His apparatus, consist- clune"*' ma" m& of a portable rolling press, a receptacle for keeping very thin unsized paper in a due state of wetness, and a peculiar ink more mucilaginous and less speedy in drying than common writing ink, is at present in general use, particularly in mer- chants' counting houses. In a former Journal it was remarked, that sugar or treacle, added to ink, gives it the disposition to come orTupon wet paper, and that if the paper be well soaked, so as not to shine and yet to be considerably transparent, a very light pressure, such as that of a warmed flat iron, would pro- duce the copy. It is to be regretted, that this ingenious application shoul require as much apparatus and skill as it does j though its requires pre- value is undoubtedly very great. The following process is less apparatus, ^ neaf> °ut ITiay be practised wherever a round ruler and gauze pa- per, or blotting paper, can be had. I have availed myself of it on a journey ; in which it first occurred to me as an expedient for copying' letters. The process. — Roll a piece of guaze paper upon a small sound ruler, and place the ruler, thus covered, upon the sheet of Another pro- paper intended to be written upon, in such a manner as that. the bet rlcdsedln ™ler shal1 be Just above> and parallel to the intended first line, a! I situations, and the outer edge of the gauze paper on the same side as the upper edg? of the paper. Then write the first line, and imme- diatelyupon concluding the same, roll the ruler just upon it j and the gauze paper will receive a print of that line. Return the ruler to its first position, write a second line, and take a print of that as before, — And in this manner the whole letter maybe copied while writing. I found a little awkwardness at first, in bringing myself into the habit of this manipulation j which requires the writer to recollect, at the end of every line, that he is to apply the gauze paper j but this was soon over- come. And it may also be observed, that for a very light hand, wfcich dries quickly, it would probably be needful to apply the ruler at shorter intervals. My hand writing, which is neither heavy USEFUL NOTICES. 1 15 heavy nor light, admitted of the operation being performed, aS before directed, but I could not defer it to any second line. Another artist, of the name of Wedgewood, has, within ft Art of making few years past, offered to the public, under sanction of Letters copies byblack 3 * ' r tracing paper. Patent, the engraver's method of tracing, by means of a piece of paper blacked with a pigment, (commonly lamp-black) applied by means of fat or a slowly drying oil. If such papdr; which is sold at the shops, by the name of black tracing paper, be laid upon a leaf of common paper, and another leaf be laid upon that, the whole being disposed upon a firm flat table or plate of wood, or metal, or glass, and any writing be made with a small rounded steel or glass point, two copies will, by the same ope- ration, be produced ; viz. a reverse copy on the upper white paper, and a direct copy on the lower; the latter of which is sufficiently durable to be sent away to a correspondent, and the former will be very legible, as a direct copy, if the paper be thin. Dr. Franklin mentioned to the Abbe Rochon* a method of A method of rapidly engraving or marking plates, for multiplying copies. "in^upL^nd He wrote with gummed ink, upon a surface of hard stone or printing from a iron, and powdered his writing with sand, or emery, or cast metallic Plate- iron dust ; and when dry, he applied another plate of soft wood, or pewter, or copper, upon the surface, and forced the gritty matter into this last by the action of a press. This last served, in the usual method of copper plate printing, to give a very great number of copies, not neat or beautiful, but suffi- ciently legible. The Abbe Rochon proposes, as a better method, to write Another by with a steel point upon a copper plate ready varnished, and etch j^jjj]*' *n the face by a«]ua fortis. Reversed prints being taken from this ter-proofs. etching, he piles these, while wet, along with other damped paper, and passes the whole through a press, which gives an equal number of counter proofs not reversed. Both the last mentioned methods may be of use in armies Improvements and under oiher circumstances : but both suppose extensive •*u£gested« means and apparatus, and only dispense with the engraver's skill. Perhaps it would be an addition to Rochon's method, that the' * Rccueil de Memoires, &c. from M L'Abbfc RvjcKoh, ocUvo, Paris, 1 73 J, p. 313, 1 2 etching I 1(5 USEFUL NOTICES. etching should be omitted, and the writing made upon soft metal with a sharp point leaving the bur on. Such a plate would afford many impressions. It would be a great improvement upon Watt's method, if the Counter-proofs could be taken upon dry paper. The tracing paper of Wedgwood and the engravers soon loses its colour, and it will not keep long. It soon becomes too dry to give off its colour. 2. Scintillation of the Stars. Twinkling of Many speculations have been offered to account for and explain the stars as- r ..... /- ,- i r cribed to the that apparently irregular and agitated emission of light, from »ir« the fixed Stars, which has been called scintillation or twinkling. From its marked appearance at low attitudes, and almost total absence at higher, it has been commonly ascribed to the interposed atmosphere j which, by the changeable densities of its parts, and the interposition of opake particles, is imagined to produce variations in the quantities, colours, and directions of the light before it arrives at the eye. In^proof of this doc- trine it has been farther noted, that the stars do not scintillate in a telescope. Undoubtedly the effect is still clouded with un- certainty. An observation I made upon the Dog Star (Sirius) in the autumn of ISO/ may be considered as affording a few facts more m addition to those we already possess. The stars do It is not true that the stars have no scintillation in a tele- Stelwope* m scope. It maybe strikingly observed by putting the instru- ment out of adjustment. In this case the circular disc of light, has a kind of vaccillation, as if a number of discs were continually flashing before each other : the illumination seemed to come on at different sides, and these discs also differ in colour. but give co- Blue, steel blue, pea-green, bright copper, red and white, are loured rays in amone the most usual colours: but the rapidity of succession succession. » ' , , , i does not allow the sense to determine whether these colours may be more or less cotemporaneous, or completely and dis- tinctly succeeding each other. To determine this point, I An experi- took an achromatic glass of Ramsden's, magnifying 24 times, coloured ^9 and direcled lt to tbe star — l^e obJect en(1 beinS supported of the Dog in a notch in a steady bar connected with the wtfU^&nd the eye Slar* end, upon an adjustable piece wnich was likewise capable of S ..being USEFUL NOTICES. 117 being set very steadily. But upon this I rested my left hand, between the finger and thumb of which I held the eye end of the glass. In this situation, the glass being truly adjusted to distinct vision, I conld observe the star, and by gently and rapidly striking the tube with the fingers of the other hand, I caused the image of the star to dance in the field of view, and describe the same kind of luminous line as is seen when a lighted coal is whirled about. The star was thus made to describe by each blow a curve returning into itself ; but so contorted and irregular that no two successive curves were coincident with each other. The strokes were about ten in a second of time, and the curves were beautifully and The rays were distinctly tinged with different colours in their successive parts beautifully thro' different lengths : but it seemed at a medium that each vivid, of these vivid colours might occupy afeout one-third part or less of the whole curve, and upon my recollection those most predominant were greenish blue, steel blue, and maroon or an in- tense copper colour. The light from Sirius therefore as it arrived and varied at the eye was by extremely sudden variations distinctly chane- thirty time* . . . . . , . . . , *t , in a second- ed in its colour, at least thirty times in one second. No theory deducible from the known properties of the atmosphere, as an interposed medium, has yet presented itself to my mind, in a shape worthy of notice. In the collection last quoted of Rochon, p. 380, he observes, Correspondent that the scintillation of the fixed stars is an obstacle to mea- fzc} Wlth» suring their diameters, and that when the light of Sirius was refracted into colours by a prism, it had no scintillation across the spectrum. As far as may relate to the apparent diameters of the fixed stars, the observations of Herschel do not seem to support the deduction of Rochon j but his fact appears to correspond with mine. 3. Advantage of upsetting or pressing in the borders of plates offlintglass to make the concave lens in achromatic combinations. The same Abbe Rochon p. 372, remarks that the triple object J»rge achr©. lenses of Dollond of 3£ inches aperture, produce an effect matIC Iense' equal to that which it seems ought to be obtained from the lenses of 30 or 40 feet, made by Campani. Rut that in making achromatic lenses of longer focus, the plates of glass cannot be being blown, are too thin to be worked without bending and made for want spoiling the figures. All the cast glass he tried was found to giTW ,H* N 11 8j USE^vi; NOTICJf*. M°eriorTto9 " ^ m°r tlian the blown glass. It woujd not be difficult to ex- plain this from the circumstances of the making; but the principal object of the present notice is, to mention that he succeeded in making a thick lens out of plate one quarter of Blown p^ate an inch in thickness, by softening the glass by heat upon an g'oSk d™7 ^ eartnen momd of tr,e proper curvature, and upsetting or pres- thicker. &'wg the borders inwards, (taking care to avoid folds or wrink- les,) till the. edge was an inch thick, and the diameter five inches. He then surrounded the gJass by a metallic ring of six inches diameter, and three quarters of an inch deep. Within this ring he again heated the glass, upon which he previ- ously placed an upper convex earthen mould. The glass A lens, made thus obtained appeared very goocl, and when ground and po- sn this manner, }ished enaoled him to make a triple object glass of seven was excellent ; r J ° feet locus, producing, as he says, a much greater effect than the glasses of Dollond, but without admitting of a proportionate aperture. For the lenses of that celebrated artist bore an aper- ture of 42 lines, and his lenses would not admit of more than 4 inches or 48 lines; which, however, adds more than one third to the whole quantity of light. From the great care ki working, he did not think that the external parts of the fcutthebor- lens were defective on account of the figure. Tiie defect probably from ar0:je most Pr°bably from the flexure and contortion of the the glass aud grain of the glass in pressing in. For an ingenious philoso- not t e figure, ^ical artist has assured me, that there is great difference in lenses and prisms made of the clearest plate glass ; accordingly as the line of vision is directed at right angles to the natural plane, or more obliquely or coincident with it, the latter being in general good for nothing. Whence, and . from other facts, he inferred that the layers of glass plates differ consi- derably in their densities. CONGULATI0N OF MERCURY. 119 vr. An Account of some Experiments on the Congelation of Mercury, jij means of Ether. By Alexander Marcet, M. D. F.R.S. To Mr. Nicholson. Sir, MR. Leslie's new and ingenious mode of illustrating the Account of ^ well known fact of the production of cold by evapora- m^'ho/of6 * tiori, by actually freezing water, in consequence of a rapid freezing, process of vaporization from the water itself, has already be- come a familar experiment. Water is placed over an open vessel, containing sulphuric acid, and the whole being inclosed within the receiver of an air pump, the water cools as the exhaustion proceeds, and is ultimately converted into ice. I have learnt also, that Mr. Leslie has succeeded in freezing mer- cury by a similar process ; that is, by investing the bulb of a mercurial thermometer with a thin coat of ice, and exposing this to the joint effect of exhaustion and of sulphuric acid. After trying to repeat the last of these experiments, (an Mercury froz- attempt in which I did not succeed ) I effected the congela- S^f ether*" tion of mercury with great facility and quickness, simply by substituting the evaporation of ether, instead of that of water, in the process in question. I am not aware of having been anticipated in this experiment j if I have, you will oblige me by taking no notice of this letter j but, in the contrary case, I shall thank you to give it a place in your Journal. The mode in which the experiment is made is this : a conical Method of receiver, open at the top, is placed on the plate of the air pump, p^mcot.*6*" and a mercurial thermometer is suspended within the receiver through the aperture. This is done, like some of the well known pneumatic experiments, by means of a brass plate per- forated in its centre, and fitting the receiver air tight when laid upon its open neck. The thermometer passes through this plate to which it is carefully fitted by a leather adjustment, orsim- ply by cork, secured with sealing wax j and it is so graduated, that when its bulb is sunk a few inches within the receiver, the stem rises externally through the plate, above which the scale begins 120 CONGELATION OF MERCURY. begins. The bulb is then wrapped up in a little cotton wool, or what is better, in a little bag of line fleecy hosiery j and after being dipped into ether, the apparatus is quickly laid over the |-eceiyer, which is exhausted as rapidly as possible. In two or three minutes the temperature sinks to about 45 below 0, at which moment the quicksilver in the stem suddenly descends with great rapidity, (in consequence of the remarkable con- traction which the mercury in the bulb undergoes {n congeal- ing) to a distance corresponding to between 300 and 400 de- grees. This, however, seldom happens to that extent, because the descent of the mercury is often impeded by the freezing of the column itself at the entrance of the bulb, before the congelation within the bulb is completed. ^he facts par- If it be desired to exhibit the mercury in its solid state, cotn- tICV ar y 6'a" mon tubes may be used, which should be broken instantly after being removed from the pump. I have frozen in this way bulbs of an elongated shape, about an inch in length, and near an inch in diameter. The pump I have used for these expeii- ments is one of a small size j* the gage of which stands at about a quarter of an inch, when the exhaustion is pushed to its utmost extent. I have occasionally succeeded in this experiment, when the temperature of the room, as well as that of the ether, was about 50° $ but the certainty of success is much increased by operating in a room, the temperature of which does not exceed 40°, and by previously reducing the temperature of the ether. I have been in the habit, in making this experiment, of inclosing sulphuric acid within the receiver, as in Mr. Les- lie's process, as it has appeared to me to promote the evapora- tion of the ether, and the production of cold ; but the experi- ment has also succeeded without the assistance of sulphuric acid. Variationof the The same experiment may be varied by first dipping the bulb experiment. Gf the thermometer, surrounded with cotton wool or flannel, into water, and after freezing this by means of the pump, pour- ing a few drops of ether upon the frozen bulb, and exposing it again to the effect of exhaustion. This plan has sometimes Made by Mr. Bate, instrumen t maker in the Poultry. succeeded MERINO WOOL, J21 fupceeded when circumstances were not sufficiently favourable for the success of the other. I have applied a method, similar to those just described, to the Water frozen, freezing of water, by means of the ingenious instrument ima- J^ *?rp pl,"mp gined by Dr. Wollastotv*, tp which he has given the name of to Dr.Wollaf- chryophorus. This, instrument consists ip a tube, terminated at tons ins^ru~ ment. each extremity by a ball, like the common pqlse glass, one of these being full of water, and both the balls and tubes being completely exhausted of air. By plunging the empty ball into a mixture of salt and snow, the water in the other ball, though at some inches, or even some feet distance from the cold mixture, is frozen in a few minutes. But by a process, similar to that I have just described, for the congela- tion of mercury, the same may be effected without any cooling mixture in less than one minute, and with a pump of very mo- derate power. I may take this opportunity of mentioning, that having constructed an aparatus of this kind, with a thermome- ter within it, I observed that the temperature of the water sunk to 20° ; and, in one instance, even two or three degrees lower before it froze, which I at first ascribed to the water b?ing deprived of its air by previous boiling ; but the same cir- cumstance not having uniformly taken place, when the shape and size of the apparatus, and the quickness of the process, were varied, I am now inclined to ascribe it to other causes. I have the honour ro be, &c. &c. &c, ALEXANDER MARCET. Russell Square, 22nd Jan. 1813. vir. Observations upon the best state in which it is advisable to bring the British Merino Wools to market. By Edward Sheppakd, Esq. of Uley, in Gloucestershire. MR. SHEPPARD lias made his title good to that fame Introduction, which attends the patriotic and well-directed exertions * This apparatus was described a few weeks ago, by Dr. Wollaston, in a paper which was read before the Royal Society, an abstract of which was published in the 1st number of Dr. Thomson '$ Annals of Philosophy. Of J 22 MERINO WOOL. of so -many of our country gentlemen, in improving our valuable stock of first materials. Wool has, for centuries, been considered as one of the first, and Mr. S. has claimed and received the Gold Medal of the Society of Arts, for having produced from his flocks of 1929 Merino and Merino Ryland, the whole bred and kept by him, 7749 lbs. of wool in the year 1812. He has communicated the following observations to the society. The Author's Having had the experience of more than ten years, both in experience in tne growth an(j manufacture of British Merino wools, which, the growth and ° . • manufacture by the constant use of the Spanish rams that came into his of wool. Majesty's possession during that period, I have brought to very great perfection ; I take this method of making public the result of my observations, as to the mode most profitable for the grower and manufacturer, to prepare the Merino wools for the market ; as considerable difference of opinion and practice prevail on the subject. The superior I had the honour, in the year 1800, to present a memoir to SsKorTand ^ the Board of Agriculture, in a successful claim I made, for Anglo-Merino the Gold Medal given for the greatest quantiry of fine wool, wool arises grown within the year. I therein stated my opinion, that the being kept in principal cause of the superior and characteristic softness of the their grease. Saxon and Anglo-Merino wools, was, their remaining in their native grease, without its being expunged in the extreme degree practised in Spain. Excepting the moderate washing that Saxon and British wools receive on the sheeps' back before shearing, they continue in their grease till they are worked up The wools of by the manufacturer ; while the wools in Spain, as soon as Spain are shorn, are thoroughly scowered, by an injudicious process, and too much then exposed for days to a burning sun, in which brittle and •cowered, hard state they are so closely packed up, that they come out of their bags here, almost as much pressed and hard as hops, wholly deprived of that unctuous preservative, which I con- ceive to be necessary to the soft feel of wool, ami would It has been thought by some, that Saxon and Anglo-Merino most probably woo]s have a softness peculiar to themselves, and different be soft if bet- \ , , . , /• ter mauaged. from the Spanish, their parent stock, obtained from their cross MERIWO WOOL, 123 cross with another and coarser woollen sheep. I am, however, very much disposed to attribute the quality here spoken of, to the better management of the wools in this country. Unfor- tunately, we have no opportunities of discovering what Spanish wool would be preserved in the grease j as the mode of laying on the duties at Burgos, by the pound, prevents the grower or merchant exporting it in that condition. Otherwise, I am much inclined to think the same softness would be found in the pure parent fleece, as in the spurious offspring. From the small experience afforded by the ill-conditioned fleeces lately imported with the sheep from Spain, I am very much con- firmed in my opinion. Lambs' wool, not being so completely washed from its grease Lambs' wool in Spain as sheep's wool, comes very near to the softness of cleaned and is the Saxon and British lamb's wool. As a proof of their pos- »ofter. sessing an extra quantity of grease, they are much sooner liable to breed the worm than Spanish sheep's wool. I have often proved, in the manufacture of wool, that where it has been long saturated with oil, artificially, the fibre has been lubri- cated with it, and the cloth very superior in feel and softness. It has long been known to manufacturers and wool-staplers, Veil wool is that the wool of dead sheep, or Veil-wool, as it is cailed, is because" very harsh, and quite unlike the same wool shorn from the cleared of all sheeps' back, occasioned by its being disengaged from the skin, £rease> by the fell-monger, by the action of lime, which entirely dries up and destroys the oily particles. May it not, in some mea- sure, arise from the cause, that wool from sheep used to calca- and this may reous or silicious soils, is of a harsher description: as those ^e t'?e Cills.e r harsh wool on from the Sussex, or Wiltshire downs, when compared with chalky soils. the fleeces grown on the argillaceous lands of Hereford and Shropshire ? The absorption of the native grease, by the fre- quent contact of the sheeps' coat with the soil, and the dust from it, may help to remove that great preservative of softness, and leave the fibre exposed, unprotected by moisture, to the action both of the sun and rain, which, in those exposed situations, would act with double power. From the above theory I would wish to deduce a few infe- Inferences: rences, which may be of service in the growth and manage- ljiat ^}e. sheeP ment of British fine wools. In the first place, I am satisfied tected. that nothing can so much tend to preserve this necessary state of 224 MEftlNO WOOL. of native grease, as the protecting the fleece from the humidify and inclemencies of climate. In a country where such exist in any great degree, it would be requisite, in order to attain and preserve a superior degree of fineness, that the sheep be housed in the winter, as practised in Saxony, and the northern parts of Germany, where they not only cot them in the winter, . but drive them under cover at every thunder-storm in summer. m& not often The frequent washing of a sheep's coat, wilt very much deprive ■ it of its grease, as is evident from comparing the external part of the fleece with the internal. The same comparison will show how greatly such washing has impaired its fineness. The ~ closeness of the coat of the Spanish sheep, compacted as it is, by its vast diffusion of grease, into almost a coat of mail, pre- vents the admission of the rain infinitely beyond that of any other sheep we know of ; and accordingly protects the quality of the wool longer from deterioration. But even the Spanish fleece, by constant exposure to a humid climate, and to driving winds, and rains, will be penetrated, and every year become- more open and hollow, and less tenacious cf its native grease, and, in proportion, less fine, and thai the My opinion, as to the best mode of preparing Merino wool ileeces should for tjie market, is, that where a certain and ready sale offers* he kept in the ..,.,.,..,.. . . , . . . ■ grease as long '* should be left wholly in its native grease, without being as may conve- washed on the sheep's back. This further advantage attends it, ^ ' that the fleece is much more captivating to the eye, and the fibre appears much more silky and fine. I fear, however, that there is not, at present, that quickness and certainty of sale, which will permit the grower to produce his wool in this condition. For if tbey have a chance of lying a long time in the grease, they will heat and be injured. I cannot, therefore, recommend it as a general practice, but I think where wools are likely to be used within six months of shearing, there can be no objection. The wot)I may to keeping them in the full grease. I have, however, the be washe?Ury satisfaction to state, that by the moderate degree of ablution,, while grow- which takes place in washing the wool on the sheep's back, the grease js not expunged in a degree to injure the softness of the fibre. The same mode is practised in Saxony, and is altogther different from the complete washing in hot and cold water, which the wool receives after being shorn in Spain. Tb* MERINO WOOL. 1%J The waste on British Merino wool, which has never been Clean wool bashed on the sheep's lack, is rather more than one half, or half ofTanvc about lOlbs. in 20, reckoning to its clean picked state. The wool in the same wool, when washed on the sheep's lack, loses with the ffrease- manufacturer about one third, or from rj to /lbs. in 20, which is about the average of the waste of Saxon wool. Whereas, the best imported Spanish wools will not waste more than half that amount : viz. from 3 to 4lbs. in 20. It is obvious, that a proportionate difference must be made in price, for the different conditions in which British Merino wools are pro- duced ; the manufacturer will be better able to estimate the probable waste of the wool that has been washed on the sheeps* back, as there is so much dirt, sand, and filth, generally with the wool in its genuine, unwashed state, that the waste must be always uncertain. I think, therefore, that wool washed on the sheep's back will be the most merchantable. I would also remark on the most preferable mode of manag- Lamb's fleece ing the lamb's fleece, which I should recommend cutting, ^i"/ in preference to remaining on the lamb, till he becomes a yearling, as practised by many. The external part of the hog's fleece, which was the original lambs-wool, suffers most materially from the inclemency of the weather and the winter. In its state of lambs-wool it is beautifully soft, but being af- terwards protruded from the new coat, it is in that condition exposed to the snows, winds, and rains of the winter, by which it becomes entirely deprived of its grease, and as coarse as the wool of our common country sheep. The deteriora- because it i* tion of this exposed part of the fleece, in one season only, {J^ej^osure fully proves what effect climate and weather have on the fibre of wool ; it is therefore certainly desirable to shear the lambs, as in Spain 3 and although the covering may be more complete for the young sheep against the winter with the lambs coat on, yet the being rid of the incumbrance of a wet draggled fleece, in deep soils and bad weather, is of great advantage to the young and tender sheep. EDWARD SHEPPARD. Vleij, Gloucestershire, March 5, 1812. General 126 ATMOSPHERIC ELECTRICITY. VIIL General Results of Beccarias Observations upon the Electricity of the Atmosphere during serene weather j together with those of Romayne and Henley. Abstracted by a Correspondent, (R.B) To William Nicholson, Esq. SIR, AFTER the systematic arrangements of clouds by M. Luke Howard , and his speculations upon their formation and disappearance, which I consider as having greatly enlarged and regulated our knowledge and means of making atmospheric researches, — and particularly from the probability that the dis- position, and even the notions of clouds, may be in a great measure referable to the ordinary phenomena of electrified bodies, I have thought it would be of service to the inquiries of other observers, to send you an abstract which I made for myself, of the facts and remarks of these very diligent and faithful observers j whose works, from their extent, their dispension, and even their date, though well esteemed by philosophers, are at present less likely to be referred to. At all events, I submit to your judgment, and am, without farther preface, Sir, Your most obliged reader, R.B. Value of The numerous and important observations of Father Giam- Beccaria's batista Eeccaria, on Atmospherical Electricity, render his con- observations, clusiohg. on thls subject highly estimable. His treatise annexed to the English translation of his Artificial Electricity deserves to be consulted. At present, 1 shall do little more than give his propositions or general results. Apparatus, a The apparatus by which those results were obtained, was long insulated settled on the pleasant hill of Garzegna, in the neighbourhood to'the auuos-6 of Mondovi -, from which the whole compass of the Alps, as phere. well ATMOSPHERIC ELECTRICITY. 1 27 well as the whole plain of Piedmont is easily discovered. It consisted of an iron wire one hundred and thirty two French feet long, extending from a stack of chimnics, over which it was raised by a long pole to the top of a cherry tree. Its extre- mities were insulated and defended by a small umbrella of tin, covered beneath with sealing wax. From this wire, another was introduced into a room through a pane of glass. It was found 1. That the electricity, during serene weather, in its ordinary P»th balls were ,,.-.,-,. .. ... * connected with or mean state,causes two balls of pith of elder one line inaiameter, t^e wirc to diverge six lines from a small plate of metal placed between The electricity them. The balls were suspended by very fine treads, sixteen lines stantiy positive long. 2. In the state of its greatest intensity the divergence of in clear wea- the balls is fifteen, twenty, or moie degrees from the metal. Tt 3. In its weakest state the balls move towards a conductor at a very small distance. 4. The electricity is sometimes so slow in its accumulation as to require one minute to become again sensi- ble, after having been taken off by touching the wire j but at other times it became again sensible in the time of one second. 5. That it is always of the positive kind, excepting in some very rare instances, when the contrary happens,in consequence of the wind blowing from some other part of the sky which is not serene. The instances related by Beccariaare very curious. Father Beccaria used an hygrometer consisting of a string of He used an 1 thirty-two flaxen threads twisted together to the thickness of flaxen^nread0 two thirds of a line. It was twelve feet long, and the lower and another of part passed round a pully which carried an index. The stretch- oat eai ' weight was two pounds. Such an hygrometer commonly served him a year, and he distinguished smaller mutations than it was capable of shewing by means of another hygrometer made of a twisted rye-stalk. 6. During clear weather the moisture in the air is the con- Tlie electr,cItT i t- i i • i • . i i • , ,n dear wea- stant conductor of the atmospheric electricity ; and this elec- ther is proper* tricity, is proportioned to the quantity of that moisture which tinned to the surrounds the wire, except such moisture lessens the insulation * m'° y" both of the wire and of the atmosphere. Beccaria observes, that he does not here pretend to point the . ciuse or principle which produces the electricity, but only to ascertain the medium in which it is inherent, and to the quantity of which it is generally proportioned. f. Th3 |28 ATMOSPHERIC ELECTRICITY. It is alway* 7* The electricity that takes place when the werrtlW positive at the denrs up js aiways positive. When the air takes up moisture clearing up of , , the weather, very rapidly the intensity of the electric state of the wire, as and more well as its quickness in becoming again sensible when destroyed rapidly pro- . , , , •luced as the are great j but the latter diminishes as the weather becomes dryer. evap U more It sometimes happens that the electricity thus caused continues a long time in its state of intensity, and begins afresh after being interrupted. Beccaria thinks these effects are owing to electricity being brought from great distances by the wind. Particular 8. If the sky becomes clouded over the place of observa*- observations of tion> and only an high cloud is formed without any secondary figures' and clouds under it, and the cloud itself be not part of a cloud that changes, and drops rain elsewhere, then the electricity of the wire is either taut electricity. Pos^ve or null. But if the clouds resemble locks of wool moving to and from each other j or if the general eloud is forming very high and is stretched downwards like descending smoke, then a frequent positive electricity commonly takes place, which is more or less strong in proportion to the quickness wilh which the cloud is forming, and foretels the quantity and suddenness of the rain or snow which follows. 2. When a rare, even, and extensive cloud is forming, which darkens the colour of the sky, and renders it grey, positive electricity, very intense and speedily recovering its intensity when taken off, is produced j which state diminishes and even fails as the gathering of the cloud slackens j but on the contrary, if the cloud con- tiuues to increase gradually by the accession of smaller clouds, resembling locks of wool which are continually joining and Fogs give separating, the positive electricity usually continues. 3. Low " and thick fogs (especially when they rise into a superior air con- siderably free from moisture) carry up to the wire electricity which gives frequent small sparks, and the balls diverge between 20' aud 30°. If the fog seems stationary and continues to environ the wire, the electric signs soon disappear j if it con- tinues to rise and another cloud of fog succeeds, the wire is again Rockets made electrified, though less than before. Sky rockets sent through Ma otf such thick low and continued fogs have often afforded our celebrated observer signs of electricity by means of a string, affixed to them. He never* however, observed in any of the above circumstances, any signs of negative electricity except once by a sky rocket sent through a fog, in which he saw the star ATMOSPHERIC ELECTRICITY. 129 star of electric light denoting negative electricity, but thinks that he might have mistaken its figure. As Father Beccaria in this place mentions his two fellow Romayne and labourers, Romayne and Henley, I shall here take occasion to notice their observations, and then resume my subject. Mr. Romayne* made his experiments between the year ^ . Romayne's 1761 and 1772. He held an electrometer, consisting of two apparatus, an cork balls, suspended by threads six or seven inches long out of ^ ™™tfe* a a garret window, by means of a pole five feet long; and to these, pole, when elecrified, applied excited glass, or sealing wax, by the help of another pole, and by that means determined the kind of electricity. He found the air at a proper distance from buildings, He found ships' masts, &c. to be very sensibly electrified during winter, in Jricity. foggy or in frosty weather; less so in mists, and still less in calm and cloudy weather. But in summer he never observed any electricity, except during a fog in the cool of the evening, or at night. He never found any electricity during the time of an aurora borealis, unless a fog happened at the same time 5 except- ing once, and then it was weakly positive. He always found the electricity of the air to be of the posi- tive kind ; excepting once only,during a fog, on an uncommonly warm day in winter. When a fog became very thick, he observed that the cork balls came nearer to each other, but opened again on its recover- ing its former state ; and he also found, that rain during a fog produced the same effect, which ceased as soon as the rain was over. Mr. Romayne also observed that the smell of fogs, and fre- Smell of fogs quently of the common air, resembles that of an excited tube, trie spark He observes, that when the density of fogs floating near the earth increases considerably, the balls always approach ; but that the reverse generally hapens when the fogs are high in the air. He once saw a struggle between breezes from N. W. and S. E. at the same time in which the one seemed sometimes to prevail and afterwards the other, The contention was preceded by a smoky haziness, like a fog, which occasioned the balls to diverge; as the haziness thickened they separated more, and the * Phi!.Tran9. Vol. LXII. p. 137. Vol. XXXIV.— No, 157. K repelling 130 ATMOSPHERIC ELECTRICITY. repelling power was augmented in proportion as the drops in- creased. On this occasion, M. Romayne was the first who made an elegant experiment, to shew, tlfat the diminution of surface increases the intensity of electricity in bodies. He found, by repeated trials, that a piece of flannel, silk, &c. excited and suddenly twisted, not only struck at a greater distance than before, but sometimes emitted parcels of fire into the air. And from this he infers, that the electricty of vapour, when not in contact with the earth, ought to increase by condensa- tion. This is still farther confirmed by the experiments of Volta and of Bennet, on the electricity of vapour*. Sudden chang- At other times, M. Romayne made use of a tapering tube of es of deem- t;n^ twenty feet long, and ending in a point, insulated, and city, which . , _ . , ' - , might be ex- projecting upwards out of a window. He took rn^ice of that plained byedr- uncertainty and frequent change in the electricity of clouds, servations. ° which was before remarked by Dr. Franklin and ethers ; and, after several ingenious observations, he expresses his wish, that two or more persons, at a sufficient distance, would correspond by signals, indicating positive electiicity by a red flag, and nega- tive by a blue ; as it is highly probable that much more satisfac- tory knowledge would be thus obtained, respecting the electri- city of the clouds, thunder, &c. than any single observer could acquire. The observations of Mr. Henley f tend to corroborate those of Mr. Romayne, but do not lead to any further conclusions. General fact*. I now proceed in the enumeration of general facts, or the propositions of Beccaria. .Single clouds g. In clear weather, when a low cloud, considerably distant fntensity in the f>'°™. any other, happens to pass slowly over the wire, the posi- wire. Separate tive electricity is usually much diminished, but is not rendered masses increase negatjve . an(i^ when the cloud is gone, it returns to its former state. But, if numbers of whitish clouds, resembling locks of wool, continually uniting and separating, remain over the wire, so as to form a considerable extent, the positive ekctri- * And more fully by the condenser and well-known experiments, made with Bennetts gold-leaf electrometer. T Ph. Trans, vol. C2. p. 145, and vol. G4. p. 422, cry ATMOSPHERIC ELECTRICITY. 13£ •ity commonly increases. The electricity never becomes nega- tive in either of the above cases. Father Beccaria, in his experiments on the electrified air of a The artificial room, found that the electricity is proportional to, and there- electricity in a r .11 .«'••■ a J. i • room is pro- fore most probably resides in the vapours floating therein. portioncd to The same conclusion may, therefore, as he observes, be natu- its moisture. rally applied to the atmospherical electricity, which is not suf- ' ficient in general to produce electric figures, in electrometors which are not insulate!. The two last propositions, 8 and 9, relate to such phenomena as take place when the weather either becomes overcast or clears up. The following relates to the effects of vapour or moisture, as shewn by the hygrometer. 10. In the morning, if the hygrometer indicates a great de- in very dry gree of dryness, very little difference from that of the preceding mornnigs^elec- day, then even before sun -rise an electricity takes place, caus- shewn; but if ing junction, adhesion, or divergence, of the ball: and its tne air be not very dry the intensity is greater the drier the air, and the less that dryness electricity ap- differs from that of the preceding day. But if no suclr great pears after sun dryness obtains, no perceptible electricity takes place, till sun- rise, or a short time after. 11. The electricity of the air gradually increases as the sun The electricity- rises higher. The gradual increase begins sooner, according as ureases as the . „ . . ,. ... sun rises high- the hygrometer continues after sun-n«e to indicate a higher er> &c> degree of dryness, and as such dryness more speedily increases. This increase, both of intensity and speedy recovery, when taken off, last in serene days, when the wind is net violent, till the sun draws near its setting, provided the hygrometer keeps near the highest degree it has reached. But when the sun is near setting, and in proportion as the hygrometer retreats, the inten- sity of the daily electricity is diminished, at the same time that . . the quickness with which it is revived in the apparatus, when taken off, becomes greater. 12. Though the hygrometer may indicate equal degrees of Difference dryness in the middle of the day, on different days, yet the t^^n?^nh°eat* time in which the apparatus recovers its electricity on those are diffemt. days is less, the greater the increase of heat j and when the heat is greater, the electricity arises later in the morning, and fails sooner in the evening 13. The friction of winds against the surface of the earth is Winds do not not the cause of atmospheric electricity. Impetuous winds dimi- fricityby fric" JK. 2 , nishtion. 132 ATMOSPHERIC ELECTRICITY. nish the intensity of the electricity of clear weather. And if . they be damp they diminish its intensity, by rendering the insula- tion both of the atmosphere and of the apparatus more imperfect. Other factsand Father Beccai ia made many experiments to discover whether observations , • ', . J r . . on the friction tlie fnctionof air against conducting bodies produced electricity. of winds. He used the bellows, and also turned fans of gilt pasteboard very swiftly round on an insulated axis, but obtained no elec- tricity either in damp or dry weather. He had before observed, . that air produces electric signs, when it strikes their glass*. Ha found also that the umbrella, with an insulating handle, which the French call paratonneres, never exhibited the least electri- city when held obliquely to the wind. To these I may add, that the very sensible electrometer, of Bennet, cioes not become electrified by blowing pure air upon itf. The proposition of Beccaria does not, however, rest upon electrical experiment, but is likewise supported by a variety of actual observations on the state of the atmosphere. And though these cannot be transcribed, on account of their length, yet I am unwilling to pass over in silence his very cogent remark, that if the elec- tricity in any degree arose from the friction of winds against the ground, it would be found the greatest near the surface of the earth, but the contrary is the fact. Night elec- XIV. In cold weather, if the sky be clear, the wind not tncity m cold vi0ientj and the air considerably dry, an electricity of consider- able intensity arises after sunset, as soon as the dew begins to fall. The quickness with which the apparatus recovers its electricity after being touched, is greater than during the diurnal electricity, and it disappears very slowly. and also in XV. In temperate or warm weather, and in the same cir- temperateor cumstances of wind and moisture, an electricity perfectly warm weather. . , similar to the above takes place as soon as the sun has set ; but its intensity is not so constant, it begins with more quick- ness, rises to a state of more speedily recovering its intensity after being touched, and ends sooner. Moisture af- XVI. When the air in the above circumstances, is less dry, fectsthe insu- the electricity is less intense, by reason of the insulation being rendered more imperfect, but its quickness in recovering its * Seep. 363, vol. I. on Artificial Electricity. § 776. t Ph. Tram. rol. JLXXVII. p, SO, intensify ATMOSPHERIC ELECTRICITY. \3$ intensity after contact, is greater, as the quantity of dew is greater. XVII. The electricity of dew seems to be, in proportion to Dew acts near- its quantity, in the same manner as the electricity of rain v llke rau^ depends on its quantity; and the peculiar manner or circum- stances which attend the falling of the dew, influences the electricity in the same way, as does the peculiar manner in which rain takes place. XVIII. As rain, showers, aurora borealis, zodiacal light; Succession of have a tendency to begin afresh for several successive days, similar pheno* with the same characteristic accidents, so the electricity of dew seems to have, as it were, an inclination to appear for several evenings successively, with like characters. After these propositions relating to the dew, father Beccaria An experiment adds the following : let the air, in a closed room, be electrified, of artificial , . . , , ,./-,-,.•• dew in a room that 18 to say, the moisture and other vapours diflused in it -> let artificiallyeleo a bottle filled with water, colder than the air of the room, and trified. insulated on a stove of glass, be raised pretty high in the room, and the insulation be carefully preserved. Then the electric signs that will arise in two threads suspended to the bottle, will exactly represent the electricity of dew, for they will exhibit the different manners after which this electricity takes place, according as the electrified vapours in the room are more or less rare ; as the difference between the heat of the bottle, and of the air in the room, is more or less ; and as the insu- lation of the bottle is more or less accurate. This excellent and most industrious philosopher, after recit- ing various facts respecting the electricity of dew, concludes with the following summary observations : The diurnal electricity resembles the electricity of a very The diurnal Tare fog, which rises, becomes dilated, and by that means, con- sembVe^tha^of tinually renders the insulation more perfect. The nocturnal a fog, and the •lectricity resembles that of a very rare and subtle rain, which n.'Sht elect"- descends, becomes condensed, and continually renders the insu- »hower. lation less perfect, whenever the diurnal electricity is more constant. But the nocturnal electricity frequently fails, and only attains its greatest intensity when the increase of that moisture, which is the conductor of it, happens to take place without injuring the insulation. Noticf 134$ AFRICA IX. Notice of an Adventurer to the Interior of Africa. Interior of T^ was some time since mentioned, that a German, of the Africa. Jl_ name of Roentgen, had been making preparations to prosecute the same objects of discovery that excited the ardour of the celebrated, though unfortunate, Park ; and, penetrating into the central regions of Africa, to reach, if possible, the city of Tombuctoo, which has never yet been explored by any- European traveller. The following article on this subject has appeared in a German journal of the 8th of October, quoted in the General Chronicle. M There has been lately published, at Nenwied, an interest- ing letter from the traveller Roentgen to his brother. It reached him through Professor Hagen, who received it from Mr. Nune- mann, of London. Roentgen, it appears, after visiting Paris, Vienna, and London, had repaired to Mogadore, where he resided a considerable time ; and the letter in question, dated the 21st of July, 181 1, was written on the bank of the river TeulirTt, at the moment of his deparfure for the interior of Africa." The following is some of the most interesting infor- mation it contains : — ' During my residence at Mogadore, I was engaged day and night in studying the Arabic -, and I have succeeded in making myself to be understood by the natives of the country. I will avail myself of that knowledge of the country, and of the manners of the people, which I have acquired, in order to travel to Tombuctoo. I would not act with so much boldness, were I not convinced, that providence has destined me to make the discovery of the interior of Africa. My good stars have furnished me witji a companion in my travels, than whom I could not have wished for abetter. He is a German, who, when only twelve years old/quitted his paternal roof, having an irresistible inclination for roaming ; he has never since lived six months on the same spot, and is now thirty-eight years of age. He knows all the European languages, the Sclavonic excepted. Fourteen years ago, when destitute of money or protection, he was impressed by the English for a sailor, in an island of th« Mediterranean, AFRICA. 1 35 Mediterranean, where he happened to be; he was inhumanly interior of treated by them, and reduced almost to despair. His ship Afnca- anchored before Tetuan, for the purpose of watering ; and there, having struck an English officer who had used him ill, in order to avoid punishment, he escaped, and became a Mussul7 man at Tetuan. Since then, he has traversed the Barbary states in all directions, and has lately returned from a pilgrimage to Mecca. He has lived at Jamba, in Africa, as a coffee-house keeper, and at Janol, as a physician. At Constantinople, he has superintened the gardens of a Pacha. I got acquainted with him at a merchant's in Mogadore, who had hired him as a gardener. I have taken him into my service, and I treat him rather as a friend than as a domestic 5 the benefits which I shall derive from his experience are immense. ' About a month ago, I travelled with a caravan of mer- chants to Morocco, where I procured valuable information respecting the communications with the interior of Africa. ' It is impossible to convey an idea of the violent hatred which animates the Moors against Christians. Even at Moga- dore, I could hardly go abroad without being overwhelmed with" insults. I was obliged, in order to view the city of Mo- rocco, to get an escort of four soldiers, who, by orders of the government, were to keep back the populace. Even then I was often assailed by stones, one of which hit me so severe a blow on the forehead, that for some time I thought myself dangerously wounded. This hatred of the Moors arises in a great degree from our dress. ' I saw, at Morocco, preparations for the setting out of a caravan, which was to reach Tombuctoo by Tafilet and Tunt. I immediately formed a resolution to join this caravan, and I returned to Mogadore. My companion was delighted with the . plan, which I did not communicate to any one else, but to one Christian. I caused it to be reported at Mogadore, that, dis- gusted with the bad treatment I had received at Morocco, I meant to repair to Tangier, and from thence embark for Gib- raltar. This pretended project furnished us with a pretext for purchasing a mule, and every other necessary for my journey. I secretly procured some Moorish garments. Having finished mypreparations, I invited some Christians at Mogadore to a party of pleasure on a mountain, about six English miles off, whither they 136 NEW ESCAPEMENT. Interior of Africa. they were often in the habit. of going. I have there spent one day with them, and declared that I meant to proceed for Tan- gier. They will accompany me to a certain distance, and give out at Mogadore that I am on my way to Tangier. As soon as I am left alone with my fellow-traveller, I mean to clothe myself in my Moorish garb, and to enter the great road which leads from Tafilet to Morocco. From thence I shall reach Deminit, a town situated at the foot of Mount Atlas, where I shall be safe from any searches which the governor of Moga- dore might make, should he learn that I have not gone to Tangier. At Deminit, I shall join a caravan, which will pass there about that time, and with it I shall cross Mount Atlas, covered with snow, and next enter the burning plains of Tafilet. I shall remain at Tafilet with a German renegado. There are in that city a number of Germans. There are some Germans in Morocco, and to one of them I am indebted for some valua- ble information. I expect to find a German in Tombuctoo, and there I mean to remain six months, making it the centre of my observations on the interior of Africa. I shall pass for a physician : I have laid in a supply of medicines, of which I know the application. It is my wish to penetrate towards the south, and to be able to reach Wesemb, or the Cape. Should I find this too difficult, I mean to return to Europe to publish the journal of my travels ; and shall again return to Africa, where I am destined to make some discoveries.' X. New escape- ment. Description of a remontoire Escapement for Pendulum Clocks, invented ly Mr. George Prior, Jun*. THE swing wheel, A, figs. 1 and 3, Plate III, has thirty teeth cut in its periphery, and is constantly urged forwards by the maintaining power, which, in the model represented in the engraving, is supplied by a small weight, X, figs. 2 and 3 ; CD are two spring detents, catching the teeth of the wheel * Soc. Arts, XXIX. anno. 1811. The soriety bestowed a premium of 20 guineas for this invention. alternately -, NEW ESCAPEMENT. 137 alternately; these are, at the proper intervals, unlocked by the New escape, parts marked 2 and 3, fig. 1, upon the pendulum rod H, inter- «nent. cepting small pins, a h, fig. 2, projecting from the detents, as it vibrates towards the one or the other ; E is the renovating or remontoire spring, fixed to the same stud F as the deients. It is wound up by the highest tooth of the wheel, as seen in fig. 1, (its position when unwound being shown by the dotted line.) This being the case, suppose a tooth of the wheel is caught by the detent D, which prevents the wheel from mov- ing any further, and keeps the renovating spring from escaping off the point of the tooth : in this position, the pendulum is quite detached from the wheel ; now, if the pendulum be caused to vibrate towards G, the part of it marked 2, comes against the pin b, fig. 2, projecting from the renovating spring E, and pushes this spring from the point of the wheel's tooth; on vibrating a liitle farther it removes the detent D, which detained the wheel by the part 3 striking the pin (a, fig. 2) which projects from the detent ; the maintaining power of the clock causes the wheel (thus unlocked) to advance, until detained by a tooth resting upon the end of the detent C, on the opposite side ; by this means, the renovating spring will be clear of the tooth of ihe wheel as it returns with the pendulum, and gives it an impulse, by its pin b, pressing against the part 2 of the pendulum, until the spring comes to the position shown by the dotted line; in which position it is unwound, and rests against a pin fixed in the cross-bar of the plate ; the pendulum conti- nues vibrating towards I, nearly to the extent of its vibration, when the part 1 meets the pin in the detent C, and removes it from the wheel and unlocks it ; the maintaining power now carries it forward, pushing the renovating spring E before it, until another tooth is caught by the detent D, which detains the wheel in the position first described, the renovating spring being wound up, ready to give another impulse to the pendu- lum. N. B. The pin b, fig. 2, is not fixed to the renovating spring itself, but is part of a piece of brass, which is screwed fast to the renovating spring, and is made very slender near the screw which fastens it ; this permits the end of the renovating spring to give way, ifj by the weight being taken off the clock, or any 138 NEW ESCAPEMENT. New escape- any other accident, the esenpe-wheel should be moved back- roeut. wards, so as to catch on the detents improperly. The following observations are necessary to be attended to in this escapement. 1st. That the renovating and detent springs must spring from one centre, and as similarly as possible. 2d. That the force applied to the train must be so much more than what will wind up the renovating spring, as will overcome the influence of oil and friction on the pivots of the machine. 3d. That the renovating spring, when unwound, must rest against the point of the tooth of the wheel ; which will be an advantage, as it thereby takes as much iorce off the tooth of the wheel resting against the detent spring, as is equal to the pressure of the renovating spring C, against the face of the tooth of the wheel. 4th. The detent springs must be made as slender and light as possible ; though whatever force they take from the pendu- lum, by their elasticity in removing them, to unlock the wheel, so much force they return to the pendulum in following ir; to where it removed them from j therefore action and re-action will be equal in contrary directions. 5th. That it is unnecessary for the pendulum to remove the detent or renovating springs, much farther than is neces- sary to free the teeth of the wheel, as it will always vibrate up to the same arc -3 in table clocks it ought to remove them fur- ther, so that it can go when not placed exactly level, or what is generally termed, out of the beat. XL Description of a simple, cheap, and easy Method of preventing the Annoyance of steam from Boilers in Manufactories and other Places, By Mr. George Webster, of Leeds*. Easy means of PHT1HE introduction of steam into workshops and manu- conveytng Jj_ factor}es [s injurious to the articles, to the buildings, and steam and va- ■ J ' ° porupa chim. to the workmen -, and, when the matter evaporated from boilers ney, * For which the Soc of Arts gave their silver medal in 1811. STEAM CHIMNEY. 139 is of an offensive nature, it must be still more desirable to dissipate, or carry it off, in the most efficacious and simple manner. Mr. Webster, after various trials, has accomplished thisby an ascending trunk or pipe, which communicates with the chimney, and is explained in the following description, by reference to fig. 4. Plate III. A A, the brick work surrounding the pan. B, the steam chimney, made of wood, about two feet broad and six inches deep. A small opening at the back part of the pan admits the steam into this chimney ; it may from thence be carried up to the top of the building, or turned into any smoke chimney near at hand. In order to keep the water in the pan as hot as possible during the night, there are two dampers in tha steam chimney at D, and if both these dampers are shut, and the whole top of the pan covered closely over at c, the boiling water, even when the fire is withdrawn, will keep hot for the workmen till the next morning. C C, are loose boards, fitting close to each other, and covering completely the better half of the circle of the top of the pan 5 and upon this circumstance depends the whole secret of getting quit of the steam. If you remove these boards or partial coverings, the steam chimney loses all Its use. The letter b shews the part of the top of the pan which should be left open to admit to the workmen a ready com- munication with the hot water ; and through this open part a current of cold air is constantly seen to press and force the steam rapidly up the steam chimney. It is proper to add, that there must always bean empty space of two or three inches between the surface of the hot wate.r and the under part of the cover cc} so as to permit the steam to pass to the bottom of the steam chimney. To effect this purpose, and at the same time to allow the copper to be full of hot water, a rim or curb of wood F, about three inches thick, should be fixed on the top of the copper, and upon this the covering boards cc placed. This allows sufficient room for the steam to press forward to the steam chimney at all times. The cover and wood steam chimney are removeable, and may serve for another copper, if both benotwantcd at the same time. METE- 140 METEOROLOGICAL JOUR&AL, XII. METEOROLOGICAL JOURNAL. 1812. Wind. Uth Mo. Nov. 25 s w 1% E V N 28 N E 29 S E 30 S 12th Mo. Dec. 1 S 2|N W 3 E 4 E 5 E 6 N E 7 N E 8N E 9 W 10 N W 11 E 12N E 13 N E 14 N E 15 E 16 E 17 E 18 E 19 E 20 E 21 N W 22 Var. 23 N 24 N B AROMETER. Min. Med. 2989 3007 3021 3010 29'80 2977 30- 10 29 92 29'89 29*85 2995 29-88 2996 3008 30- 11 3008 3022 30 51 3051 3041 29-96 29 39 3000 29-97 2979 297 2Q-66 2920 2C)-22 29-5 29-57 2g76 29 82 3002 3030 3046 3051 29'84 29 920 30' 155 30010 29*870 29915 Thermometer. Max. Min Med. Evap. 48 47 49 47 49 50 29840 52 30 020 49 30- 1 00 4C| 30*065 48 30 185 44 30 400 42 30460 35 30 175 34 29950 35 29835 34 29 985 36 29*880 32 29750 34 29'685 35 29 430 34 29090' 34 29' 100 35 29-365 38 29-520! 38 29665I 36 2979o!'38 29 920J 42 30160 36 29-72 2996 3000 30 05 30-08 30-29 304 29-94 29-94 29-78 29-97 2979 2971 2966 2920 2898 28'98| 29-22 29-47) 29571 2976 29-82 3002 30'30 28-98J 29*882 30380 35 52 35 43 42 38 41 47 44 42 45 38 33 26 23 18 24 29 27 24 24 28 28 28 32 33 35 31 32 33 31 32 18 415 45 0 455 425 450 48-5 48*0 455 47*0 430 38-5 340 290 200 295 31'5 315 280 29-0 315 31-0 310 335 355 365 335 35 0 375 33-5 335 3668 Rain 026 015 5 Oil 027 0-18 m 3 095 The observations in each line of the table apply to a period of twenty-four ho«r.% beginning at 9 A. M. on the day indicated in the first column. A dash denotes, that the result is included in- the next following observation Meteorological Journal. REMARKS. 141 Eleventh Month, 28. The sky, about sunset, was over* spread with Cirrus and Cirrostralus clouds, beautifully tinged with flame colour, red and violet. 30. a. rn. The sky again much coloured. Twelfth Month. 5. The weather, which has been hitherto mostly cloudy, with redness at sunrise and sunset, begins now to be mora serene. 6. Hoar frost. 7. A little appearance of hail balls on the ground. 8, 9. Clear, hoar frost. 11. Snow this morning, and again after sunset. 13. An orange-coloured band on the horizon this evening j this phenomenon arises from reflection by the descending dew. 15. A gale from N. E. unac- companied by snow, came in early this morning. 1(5. a. m. The wind has subsided to a breeze, and there now falls (at the temp, of 27'5) snow, very regularly crystallized in stars. 17. a. m. It snowed more freely in the night, and there is now a cold thaw, with light misty showers. 18. A little sleet, fol- lowed by snow. Ice has been formed in the night, by virtue of the low temperature which the ground still possesses. A wet evening. 21. A little rain, a. m. 22. A dripping mist. 24. Cloudy j a little rain 5 some hail balls in the night. RESULTS. Prevailing winds easterly. Barometer : greatest observed elevation, 30*51 in. ; least 28*98 in. ; Mean of the period 29*882 inches. Thermometer : greatest elevation 52° ; least 189. Mean of the period, 36*68°. Rain and snow 0*95 inches. The Evaporation during this period has not been ascertained. Plaistw, L. HOWARD. First Month, 7, 1813. 142 PRINCIPLES OF CHEMISTRY. Tht affinity of chemistry "plained. Absolute or complete union of prin- ciples, does not ap- pear in our observations. xnr. An Explanatory Statement of the Notions or Principles upon which the Systematic Arrangement is founded, which wai adpotedas the Basis of an Essay on Chemical Nomenclature*, By Professor J. Berzelius. WE may consider the affinity of chemistry as a tendency by which bodies are incessantly urged. By this affinity they are disposed to combine, in such proportions and in such numbers of each body, that they afterwards cease to manifest any farther affinity of combination, which property may from that period be considered as in a state of repose or inactivity. Such a combination or compound, which no longer shews any affinity towards ihe greater part of other bodies, may be itself called an indifferent body: If, for example sulphur, caritium, andoxigen, come into contact, they tend to combine in such a manner, as to produce sulphate of barytes j and in this com- pound the affinities of the ingredients appears to be in a state of repose ; that is to say, they constitute an indifferent com- pound. The entire tendency or activity of the affinity is, therefore, exected to arrive, by an effect, which occupies a longer or shorter time, according to circumstances, at this state of repose or indifference. If the elementary bodies were collect- ed at the same place, and all possessed an equally strong che- mical affinity, an active chemical phenomenon would ensue, which would terminate in eternal repose. No force would tend to change this state of repose, and such different com- binations as might be thus formed, being attracted by each other, by the means of gravitation and cohesion, would constitute a mass or aggregate of indifferent bodies. But this is not the construction which takes place in nature, among the surrounding bodies of that small part of the universe which is submitted to our observation. A series of mutations * The Essay was published in the Journal de Physique, of Dr. Dela- metheiie, Oct. 1811, or Tome lxxxiii. 253. It ; bounds with nevv^and interesting observations ; and it is with regret that i am preventer! by it* length from inserting it in our work. — The present memoir, which is of considerable extent, is taken from the Memoirs of the Academy of Stockholm for 1812.— W. N. take PRINCIPLES OF CHEMISTRY. 143 take place in unorganized matters, by which organized nature is supported, and we have plausible reasons to conjecture, that a similar disposition prevails in the other parts of the immen- sity of the universe. The circumstances which incessantly tend to destroy or to because pre- prevent the repose of combined elements, are light, caloric, and h>r"c jjght, and electricity, assisted by the circumstance that the chemical electricity, affinity of the different elementary bodies is not equally strong. Caloric, light, and electricity, have a mutual relation with each These have a other" j easy to be perceived, but very difficult to be compre- ™"n"* bended. Very often the presence of one of these produces the other, without one being capable of determining whence it comes. When a large and powerful electrical pile is dis- charged by means of two points of platina, a sun is produced The union of at the point of discharge ; indeed upon a scale of infinite mi- l^"^"^ nuteness as to magnitude, but which, by the intensity of its and heat, light and heat, surpasses every other phenomenon of fire pro- duced upon one globe ; which fuses the metal, and loses nothing by the comparison, even-" when produced in the midst of a' flame, supported by oxigen gas. The production of light and heat at the point of the electric discharge j that is to say, at the point where the two separated electricities it cease to manifest themselves as electricity, cannot be mistaken ; and proves, that there is a relation between these substances, which we may, per- haps, hereafter be better able to comprehend than at present. Caloric and the electricities exhibit, in our experiments, a Tendencies t« kind of tendency to acquire an equilibrium: that is to say, to equilibrium of r .-, .... caloric and e- arnve at the same state of repose, which appears to be the ulti- lectricity, mate end of the chemical affinity of ponderable matter. But this equilibrium of caloric and the electricities is incessantly broken by the rays of the sun, by which the surfaces of the planetary bodies is alternately enlightened at determinate inter- vals. There is therefore a process carried on in the sun, by which which is di*- the repose of the united elements is incessantly intercepted or |ofareJiEfti prevented, and which preserves them in a certain state of activity. It is impossible for us to determine the nature of this process ; because the truth of on rconjectures will never, in all probability, be proved in a satisfactory manner; but, not- withstanding the difficulty; it will always be a subject of interest to 244 ELEMENTS OF CHEMISTRY. to ascertain which of our conjectures may be the least impro- bable. Common fire We know that the phenomenon of fire is produced on one is produced; globe on two principal or leading occasions. 1. When two nation of bo- bodies combine j for example, in oxidation, sulphuration, the die; 2. By combination of acids with bases, Tzc. ; and 2. When the sepa- tncities! tleC* ratetl electricities mutually penetrate each other, and cease to appear as electricities. Friction and (There are, nevertheless, two other manners by which fire concession. may be pl0juce(j . namely, friction and compression. As to friction, there is reason to believe that it will be found to class itself along with the electric discharge j and compression, or* the other hand, does nothing more than drive the caloric out of a body which it contains already produced. But in the present part of our discussion, we attend only to the cases in which caloric appears to be produced, that is to say, in which we cannot conceive whence it comes). The sun is in a It is incompatible with every scientific notion we possess, state of com- tnat the phenomenon of an interior fire should be produced in bustion, j \ ... ... , , • r- the sun, by a chemical combination, or by a condensation ot ponderable substances. Such an opinion has been rejected by our ancestors, though their notions of combustion were less precise than ours j and it appears to be contradicted by the circumstance, that the magnitude of the mass of the sun re- mains constantly without alteration, at least, as far as our am! may there- observations can determine. It remains therefore as the least fore be sup- improbable of our conjecture, that a process is affected in the ported in a ■ J . . • . • state of conti- sun, analogous to that which obtains between the points by nued electric vvhich an electric pile is discharged j and we must imagine that this process, when once commenced, must, from the nature of the actual arrangement of things, continue for ever j and that, consequently, the activity of created matters is maintained, as it were, by a gyration in a circle, or by always returning again to theirfirst situation or state, as in astronomy we know to be the case with their motions in space. It is beyond the limits of human reason to determine how these processes at first began, and it would no doubt be unworthy of an enlightened and dis- cerning mind to presume seriously to form any conjecture upon the subject. The electrici- Our experiments with the electric pile, have proved how much ELEMENTS OF CHEMISTRY. 145 touch the Electricities are concerned in the operations of che- tIes are. con- • , ^ . i . . . j j cernec in the mical affinity ; and that sometimes they are suppressed, and operations of at other times made to act in an opposite sense. It was even affinity, observed, before the discovery of the Electric pile, that the Equilibrium of Electricity is sometimes disturbed by chemical operations, and the knowledge acquired from the labours of the last ten or twelve years, has shown us, that there is not a single action of affinity, in which the electricities do not co- operate. We do not know how this co-operation is made, and, for in a manner" i ,'-,.,• . not known j the moment, we must be satisfied with conjectures upon it. What we with certainty know is, that two bodies which have but bodies affinity for each other, and which have been brought into having affi- , /-j • . • nity, shew the mutual contact, are found upon separation to be in opposite e|e;!trjc state» states of electricity. That which has the greatest affinity for on separation, oxigen usually becomes positively electrified, and the other negatively. Bodies which have little affinity between them, that bochesbe' ° J . i , > , coming posi- or, which have nearly an equal affinity for oxigen, do not tive which hag sensibly derange the electric equilibrium by their mutual con- tbe strongest . . affinity for tact. This is not only the case with combustible bodies, but oxigen. it also takes place with the oxides ; as for example, the oxalic acid, dry and deprived of its water of crystallization, brought into contact with quick lime, becomes, according to the ex- periments of Davy, negatively electric, while the. lime be- E'evated tern- comes positive. And since the electric state of these bodies Peratu''e "n" r creases ihe af- is more marked, the higher the temperature, that is to say, as finities an.i the the chemical affinity becomes more active : and lastly, as at electncity» and J ' J at the instant the moment of their union there is a production of heat, of union, heat which may vary from a very slight elevation of temperature to fn*ues Pr°- i r i i cl . • . ,. bably from an that of the most intense fire, we think we may conclude, electric di3- that at the moment of the chemical combination, there is a charge. discharge of the opposite electric state of the bodies, which here, as in the pile, produces the phenomenon of fire, at the instant when the electricities disappear. A derangement of the equilibrium of electricity appears A change in therefore to precede, and as it were predispose, the action °f equ Honum the chemical affinity j though this phenomenon from physical precedes the reasons cannot be always discovered by our instruments j as may a~'"n °* * happen, for instance, when one of the bodies is in the liquid state. Davy found, in conformity with this, that sulphur, heated Vol. XXXIV.— No. 157. L upon 14G CHR0N0METRY. upon copper, gave signs of very strong electricity, constantly increasing with the temperature till the sulphur melted, at which instant the signs disappeared, aWeeboSesder" After the union of ponderable bodies, in which the electri- have combin- city is seen to fly off in the form of light and heat, the ponder- ed, they can a^je bodies are reduced to a state of chemical repose. The be separated ,.,,.. , , . only by the elements of the combination can no more be separated, nor be electricities restored, to their original form and characters, without the influ- acting pecu- _ »,'■'..'.. r , r liarly on each ence of a mass of electricity, in a state of charge or ot separa- body. tion, as in the operation of the pile. Bat in this case the elec- tricities, tending to regain their equilibrium, decompose the combination, by operating each upon its relative constituent part to which it restores its original form and characters. (To le Continued) XIV, Facts and Remarks, upon the Interruption which the situation of the maintaining iveight produces in the rate of a clock, when near the pendulum. By H. K. To Mr. Nicholson. SIR, Rate of clocks 1TN your Journal for October last, I observed a paper by Mr position of the affected by the JL Thomas Reid, on the effect produced on the going of position of the t a ° weight, clocks, by the attraction between the weights and the pendu- lum. was observ- 'f he effect alluded to, viz. that of the arc of vibration becom- died by pro-" mZ ^ess when the weight is near the ball of the pendulum was fessor remarked some years since, by the late Dr. Hornsby. This orn* ¥• gentleman having done me the honour to accompany me in a visit to the observatory at Oxford, pointed out an astronomical clock there, the weight of which he had contrived to pass behind the clock case. He informed me, that he had remarked an irregularity in the going of the clock, when the weight approached the ball of the pendulum, and attributed it to the increased CHRONOMETRY. • 147 increased resistance of the air, from its free motion being impeded by the weight of the clock. Indeed, it does not seem that attraction could produce the Reason why effect alluded to ; for, though the ball of the pendulum might *££& u be retarded in its ascent, its motion would be proportionably ascribed to accelerated on its return. attraction. I have been induced to trouble you with this, merely from respect to Dr. Hornsby's memory, and not with the slightest intention of depreciating the talents of Mr. Reid. I am Sir, Your obedient humble Servant, H. K. Ipswich, Dec. 6, 1812. REMARK. From the nature and tenor of Mr. Reid's communication I Additional concluded, that his single weight descended either in front or obs.on Mr. behind the ball, and not on one side of it ; and in this arrange- ^ icatTon" ment its attraction would add to that of gravity, whether per- ceptibly or not. I likewise requested his brother, who brought the paper, to suggest that it might be desirable to make trial of a temporary piece or mass, to be put on or taken off at pleasure, in the place where the weight had been inferred to produce the greatest acceleration $ and to keep the weight out of the limit of disturbance j this would remove all suspicion of irregularity in the train : And I would, from the ingenious observations of my Correspondent, suggest farther, that the temporary piece should be a thin shell of brass, with a solid core of lead ; which, when taken out, would greatly diminish the attraction, but not the impediment from increased resistance of the surrounding air. SCIENTIFIC 148 SCIENTIFIC NEWS. SCIENTIFIC NEWS. Mountains of Lapland, &c. Valenberg's AN Account of a Journey, undertaken in 1807, by M. Valen- Journev tor berg, has been published lately, at Stockholm, under the examining the , .. . - , -.*.•»- *■ « ^ s- l mountains of auspices of the Academy of Sciences of Sweden, Jor the pur- Lapland. pose of determining the height of the mountains of Lapland, and observing their temperature. The mountains visited by M. Valenberg, make part of the great chain which runs through Sweden and Norway, and stretches in some of its branches even to Finland and Russia. They are situated between 67 and 68 degrees north latitude, and belong to the polar regions. On several points their bases are washed by the sea, and from their summits the immense plain of the Northern Ocean is discoverable. These mountains had been onl> hitherto viewed in all their majestic grandeur by the Lapland nomade, following his flocks of deer and his game. A few travellers had contem- plated them at a distance j and M. de Bruck, a learned German, during his travels in Norway, approached within a short space of them $ but no person had ever yet penetrated into this asylum of nature, and attempted to struggle with the difficulties of ascending these summits, eternally covered with snow and ice. The undertaking was difficult in many respects. The ascents were mostly excessively steep, and in climbing them the tra- veller was by turns suspended over deep fissures, lakes, tor- rents, bottomless marshes, and gulfs. He had no intelligent guide, there was no habitation on his route, and no assistance to be expected. He frequently was obliged to make circuits of many leagues to reach a summit 5 and he crossed not only- snow and ice full of crevices, but also marshes, where he run a continual risk of being buried in the mud and stagnant water. He passed the nights on naked rocks, without a tent or the smallest shelter} and he was frequently reduced to quench his devouring thirst by swallowing snow, which occasioned him inflammations and painful suppurations in the mouth. M. de Valenberg's measurements give the Lapland moun- tains aa elevation of from 5 to 0,000 feet above the level of the SCIENTIFIC NEWS. 1^9 the sea. Although this elevation is less than that of the moun- tains of Switzerland and the Pyrenees, all the phenomena of the Alpine regions, and particularly glaciers, are observable. At such a proximity to the polar circle, the region of eternal snow commences at nearly 4,000 feet above the ocean, while in the Alps it begins at from 7 to 8,000, and in the Pyrenees at 8,000 feet. On the 14th July, M. de Valenberg ascended the most con- siderable glacier, called Sulitelma, a Lapland word, which signifies Solemn Mountain, because formerly the Laplanders adored on one of its summits their principal idol. This moun- tain, which is the Mount Blanc of the north, is composed of a succession of summits, of which the base has an extent of several leagues. Its greatest elevation is 5,700 feet above the se3. To reach this elevation, our traveller was obliged to make his way over enormous crevices, where recently before some hunters had been engulphed with their deer and their dogs. Seas of ice have descended into th 3 vailies 700 feet below the line of snow. There is a border of earth surrounds the ice, consisting of slime and stones. The ice of Sulitelma is very clear, and almost transparent; it is as hard as stone, but not so heavy as the ice of the sea. The traveller gives several details respecting its internal composition, the figures by which it is characterized, and the crevices formed on it. The snow is sometimes 100 feet in depth, and so hard that the footsteps leave no mark on it. That which is detached from the sum- mits, or crevices, roll to immense distances. Fortunately, these avalanches in their descent act only on inanimate nature : whatever direction they take they seldom encounter living beings, or the abodes of men. All is desert in these regions for vast extents, where industry has gained no conquest over the solitary domain of the primitive creation. The traveller terminates his account by general conside- rations on the temperature, and by tables of meteorological observations. He determines with precision the , different regions of the mountains, and characterizes them by the pro- ductions which he found there. In proportion as the line of snow is approached, the productive force of nature diminishes, and men, brute animals, and plants, yield to the rigour of the cold. At 2,600 feet below the line,, the pines disappear, as well 1JO SCIENTIFIC NEWS. well as the cattle nnd habitations. At 2,000 feet the only tree is the birch j and its degraded form and indigent verdure attest the inclemency of the climate j at the same time the greatest number of wild animals disappear, and the lakes contain no iish. At 800 feet below the same line of snow, the Laplander's progress is stopped for want of moss for his rein-deer. Above the line every thing presents the picture of agony and death. The most robust lichens are only to be found at 1,000 and 2,000 feet, in the crevices of perpendicular rocks j and the bird named emboriza nivalis, or snow-bird, is the only living creature to be seen. The heat does not rise to one degree of Reaumur, in the region, which is 5,000 feet above the sea. Mr. Fiddler, a captain in the Hudson's-bay service, has communicated to Mr. Arrowsmith, the draught of the district of country which lies between the rocky mountains and the great ocean, and between the latitude 52 and 4(5. It contains all the head waters of the Columbian River 5 of a lake, called, by Mr. Fiddler, Lean's Lakej a river running into it, called Arrowsmith's River j and a river of magnitude, called Wedderburn's River. The whole tract is inhabited by tribes of flat-head Indians, otherwise called Teres de Boules, and one large extent is filled with wild horses. Mr. Arrowsmith purposes to introduce these discoveries into his General Map of North-American Discoveries. Mr. Arrowsmith has completed a new Map of Germany, in six. sheets of double elephant, being the largest map of that em- pire ever drawn and published in England. Like all the maps of this eminent geographer, this new one is derived either from original or unquestionable and superior sources. The same geographer has for some years been engaged on a Map of England and Wales, in 18 sheets, which, when put together, will be 10 feet by 12. Of this extraordinary map it deserves to be noticed, that it will contain at least 1,000,000 names, which is the more remarkable because the places enu- merated in the Population Return are only 15,741 j and Capper's Topographical Dictionary does not contain ab6ve 20,000 places for the three kingdoms, although double the number contained in Luckorabe's Gazetteer. It SCIENTIFIC NEWS, 151 It is with regret that I find myself under the necessity of taking notice of some passages in the preface to Dr. Thomp- son's Annals of Philosophy, in which he animadverts upon the English Philosophical Journals. 1. Of my Journal he says, " that for several years it was in«uch manner as may appear from their pro- intensity of perty of combining in proportions of their multiples, we may Ifiniti th which contains an excess of positive electricity, consti- electro-nega- tutes an electro-positive body, and vice versd. Many bodies predominating recluire an elevation of temperature to enable them to act upon pole. each other. It appears, therefore, that heat possesses the pro- Heat aug- perty of augmenting the polarity of these bodies j and that deariciticsL ^e difference m activity of the affinity at different temperatures, appears to depend on the same cause, in like manner as the force with which a combination preserves its existence, appears to depend on the intensity of the electric polarity when this is at its maximum, or rather the intensity of that polarity at the moment the combination is made. This circumstance explains why the phosphoric acid is decomposable by charcoal at an elevated temperature, although phosphorus decomposes the air of the atmosphere at a temperature at which charcoal has no influence upon that fluid. In the theory of atoms, there is some difficulty in conceiving the difference between the juxta-portion of homogeneous par- ticles, separable by mechanical means, and that of the heteroge- neous particles, which produce a new particle, very seldom de- The particles composable by means purely mechanical. The hypothesis of of homogene- polarized atoms assists us upon this occasion. The cohesion of ous masses ap- * r pear to unite homogeneous particles may be compared to the juxta-position like the plates which we observe in the electrophore between the opposite of the electro- .... _. , „. , , . ,. phore. electricities of the metallic plate and the resinous surface Contact keeps ftfem in a state of charge or neutralization j which. ELECTRO-CHEMICAL PRINCIPLES. 155 which, in fact, is simply juxta-position, and is destroyed when the surfaces are separated, and each appears again in possession of its original electric state. When heterogeneous atoms com- Heterogene- ,.,., , ..., i.- • ous particles bine (whether the combination do consist simply in juxta-posi- seem to unaj tion, or, which is more difficult to comprehend, in a partial or by a discharge a. i \ f t* i. « i ot electricity total penetration) they appear to adjust or dispose themselves so with prtKjUc' as to touch with the opposite poles ; of which the electricities tion of heat, produce a discharge which causes the phenomenon of elevation of temperature, almost constantly apparent at the time of any- chemical combination, and the particles remain combined until their discharged poles are, by some means or other, re- stored to their former electric state. As we know, from fact and experience, that bodies of the The affinity same electro-chemical class (that is to say, bodies in which we ^^^ |{|?rC conceive that the same pole predominates) can combine, it tensity of the appears, that the force of affinity depends rather on the in- ^""haifu oa tensity of the general polarity, than of the specific unipolarity ; the 'excess ia and from this reason it may be, that sulphur has more affinity one Pole be" with oxigen, than gold or platina has, although sulphur has the other, same unipolarity as oxigen, and those metals have an opposite unipolarity to that of oxigen. It is clear, th3t when two bodies, in which the same pole When bodies, predominates, combine together, the new particle must possess g^m "predomi. their unipolar force concentrated in one of ks poles, and must, nating pole, consequently, have electro-chemical properties more intense 5 gj*™^1" che-* and this is a good reason why sulphur and oxigen produce the mical property strongest acid. On the contrary, when particles possessing an °o„,1d wilVbe opposite polarity unite, the polarity of one of the particles more intense ; most frequently predominates j for example, in potash, and in and vlce versa- most of the metallic oxides, the predominating pole of the metal also predominates in the compound. In some instances, the product is a neutral compound, in which neither of the poles predominate, such as the superoxides : in other instances, the pole of the metal predominates in one degree of oxidation, and that of the oxigen in another. The combination of polarized atoms requires a motion to Polarized turn the opposite poles to each other -, and to this circumstance Ju^\*otacj, is owing the facility with which combination takes place when other in order one of the two bodies is in the liquid state, or where both are l° conVI*ie- 1 his will oe in that state ; and the extreme difficulty, or Ifcarly impossibility, -a»ily done if M2 of 16G KLECTRO-CHEMICAL PRINCIPLES. one or both be of effecting an union between bodies, both of which are solid, can scarcely S And again, since each polarized particle must have an electric combine. atmosphere, and as this atmosphere is the predisposing cause of cases have' ° combination, as we have seen, it follows, that the particles can- less electric ac- not act but at certain distances, proportioned to the intensity of toITrcmotc * their Polaritv > and hence lt is that bodies, which have affinity for each other, always combine nearly on the instant when mixed in the liquid state, but less easily in the gaseous state, and the union ceases to be possible under a certain degree of dilatation of the gasses, as we know by the experiments of Grothuss, that .a mixture of oxigen and hidrogen in due proportions, when rarefied to a certain degree, cannot be set on fire at any temperature whatever. The pile re- The chemical action effected by the discharge of the pile, atoms to their consists in the particles in a combination being re-polarized, former state. jn 3 combination of particles having the same unipolarity, the pile merely restores, by the decomposition, the general polarity, because their specific unipolarity was not changed by their union ; but in combinations of opposite unipolarity, it likewise restores the specific unipolarity of the elements. May we conclude, that, in the first case, the general re-polarization takes place in the same manner as the loadstone gives magnetism to a small particle of steel, and that in the second, the pile con- tributes, by its own specific energies, to restore the predomina- ting poles* [Here the annotation concludes. — W. N.] Classification In my essay upon chemical nomenclature, I have divided to theh^dispo- bocUes into electro-positive and electro-negative, the first of sition to be these denominations being appropriated to bodies which, by the round^ie action of the pile, are collected round the positive pole, and poles of the vice versa, I have noticed the probability, that these names pile. Electro- had been employed in the opposite sense -, and my subsequent * In this, beautiful generalization of facts, which promises to become more conclusive the more it shall be studied, this last paragraph seems rather obscure. The poles of the voltaic pile appear to present, to the principles of a compound, points of attraction more powerful than that which maintained the combination ; and they transmit the electric energy from particle to particle, so as to complete the total de- composition, But we do not yet appear to possess analogies to carry us much farther.— N. reflec- ELECTRO-CHEMICAL PRINCIPLES. \$J reflections upon this object, obliges me, at present, to change positive attach these denominations for each other. I shall, therefore, here- *? the nega~ alter call those bodies electro-positive which are collected round tro-negative to the negative pole, and those electro-negative which are collected the positive round the positive pole. With regard to the alectro-chemical ^° - relations of bodies mutually, I shall divide them into five diffe- rent classes. 1. Absolutely electro-negative ; oxigen alone. l. Absolutely 2. Electro-negative in general ; all combustible bodies electro-nega- which produce acids with oxigen, are constantly collected at ' the positive pole of the pile. To this class the metalloids be- gative. long, and among the metals arsenic, molybdena, and wolfram. 3. Bodies of a variable electro-chemical nature. This class 3. Variable, includes (a) such bodies as, when combined with oxigen, are electro-positive with regard to the preceding class, but electro-negative with regard to the bodies which constitute the last of the subsequent classes ; (b) such bodies as, in one degree of oxidation, constitute a saline base, and in another degree an acid. Tellurium is an example of the first, and antimony of the latter. 4. Indifferent. Oxided bodies, which possess no decided 4. indifferent character, being neither acid nor saline bases. Such are the oxides of tantalium and of silicium. This class likewise includes the combinations of acids with saline bases, that is to say, the salts. 5. Electro -positive. Combustible bodies and their oxides, 5. Electro-pn- which, during the action of the pile, are never collected round sitiv*- the positive pole, and of which a great part, when combined with oxigen in excess, instead of forming acids, produce super- oxides. Such are potassium, baritium, lead, silver, &c. It is proved by experiment, that the more opposite the elec- ^ut[J*? affi" tro-chemical nature of two bodies is, the stronger in general is stronger, the their mutual affinity. A combustible body consequently tends more opposite r , . . , . , . . the electro- wilh greater force, to combine with oxigen, than with any chemical na- other combustible body with which it may have affinity. Hence tureof bodies we may conclude, that, if it were possible to obtain pure oxi- wm un-^e gen in the solid form, and if, in that state, it were put into con- strongly with tact with a combustible body, it would become much more 0XISCU> strongly electric than, for instance, sulphur with copper, and would, in, fact, produce, in combining with the combustible an<* produce body, 158 ELECTRO-CHEMICAL PRINCIPLES. elevation of body, nn elevation of temperature much higher than could be temperature produced by the combination of any other body with the same combustible. These reflections appear to indicate that, in the phenomenon of combustion, as in general in every chemical combination, the phenomenon of fire is produced by a cause analogous to that which is manifested on the occasion of the by a process discharge of the electric pile ; that is to say, by a discharge be- rescmbling the tWeen tjie opposite electricities of the oxigen and of the com- voitaic dis- . charge : bustible body, which is made at the moment of combination. and this will The same considerations also explain why the phenomenon onPthTstreneth °** **re 'l* more mtense accordingly as the affinity of the bodies of affinity, which combine is more powerful (varying from the slightest than on change e]evatjon 0f temperature to the most intense fire) without any remarkable relation between the expansion or condensation the bodies may have undergone from their union. Kence the ef- This electro-chemical view explains what was so difficult to fects of sul- ke comprehended in the time of our predecessors, namely, how phuration are L r ■ f similar ro sulphuration could produce a phenomenon of fire exactly simi- thoseof com- ]ar to that produced by combustion ; and it classes together all the disengagements of caloric or fire, occasioned by chemical combinations. As it explains, in a consistent manner, that which the old theory could not account for, it appears to deserve our confidence, or at least our attention. I shall explain my notions by an example. And charcoal Jf anv very powerful electric pile be discharged by pieces of between the charcoal in hidrcgen or azote gas, we see the charcoal become pileinhidro ignited, and produce the same phenomenon, as if it were ac- gen or azote, tually burning. A spectator, who, on this occasion, had no nited°a?in ox"i knowledge of the influence of the pile, would say that the gen ; but there charcoal was burning. But, nevertheless, there is, in this case, bu^on"1" neither oxidation nor chemical combination of any ponderable matter with the charcoal, and, notwithstanding this, the pheno- menon of fire is the same as if it had been produced by com- bustion. Now, it appears to be a well-founded conclusion, that the same effects are produced by the same causes; that is to say, that the fire in each of these cases is produced by an elec- tric discharge. The oxigen is Charcoal does not condense oxigen by burning, but, on the not corutjiistd contrary js dissolved in the gas of which the volume under- by burning ' . ° charcoal 3 and, gees no change. We cannot, therefore, assert, that the caloric of ELECTRO-CHEMICAL PRINCIPLES. 159 of combustion of the charcoal is the effect of a condensation, consequently namely, that the oxigen gas has parted with the caloric which cause(j by con, was employed in maintaining its gaseous form 5 and it is clear, densation, that the fire owes its origin to some other circumstance. Those who may not be disposed to approve the electro-chemical ex- planation, may, observe, that the fire in this combustion is pro- duced by the difference between the specific heats of oxigen gas, and carbonic acid gas. But, although it cannot be denied, nor by change that such a cause (or incident) may contribute to (or accompany) ° caPacity* the production of heat, it can be easily shewn, that it is not the principal or general cause j because the nitric acid in which the oxigen still preserves its property of producing fire with a num- ber of combustible bodies, possesses as little specific heat as the carbonic and the sulphuric acids. In like manner, the difference of specific heat between the metallic sulphurets and that of a metallic body, is too inconsiderable to afford a plausible reason for the fire produced by sulphuration. When a combination already formed, as, for instance, be- Electro- tween A and B, is decomposed by the more powerful affinity )Je£lactaI fause of a third body C, so that this last separates A from the combi- simple elective nation AB, and forms CB — such a decomposition is usually ajJnS' accompanied with an elevation of temperature, or even with fire j and this elevation is greater the more considerable the difference may be between the affinities of A and of C to B. We may form a notion, that this effect is owing to a more perfect neutralization of the electro-chemical properties of the constituent parts in the new, than in the old combination. If, on this occasion, B were oxigen, and A and C two combustible bodies, the electro-chemical nature of B must be admitted as more perfectly neutralized by C than by A j and at the instant when A is reduced to its original combustible state, it receives from C, which loses its like state, a quantity of positive electricity, equal to what it had lost when it entered into combi- nation with B. When bodies combine with others, in some instances more The properties positive, and in others more negative, than themselves, are ^rem^rkably found after these two circumstances in very different states ; as affected by sulphur, for instance, is in a quite different state in the sulphuric "J1!.- acid, from that which it possesses in the sulphuret of lead. From components," the former it can be disengaged by a number of electropositive e.^ sulphur bodies, 160 ELECTRO-CHEMICAL PRINCIPLES. and oxigen, bodies, but from the last it cannot be disengaged by the affinity which arc both 0f any electropositive body to the lead 5 but for that purpose sulph. 3cid and l he affinity of another body, more electronegative than itself, the sulphur namely oxigen will be required. Sulphur has, therefoie, occasion nay he disen- e ., ...\ ,r„ . ■ <• gaged by many *or °PP°site electricities, in order to effect its separation from d. positive these two different combinations. It is well deserving of atten- in sulphm-etof ^on' ^'at WDeD such an electronegative combustible is cora- Jeadnoel. pos. bined with an electropositive oxide, the combustibility of the the lead 'bu* *°rmer (or *lts electropositive relation as to oxigen) is consider- an e. neg. ably increased ; probably because its electronegative dispositions bodv,viz. have been destroyed by the positive electricity of the oxide. oxigen is re- J J r J quired. We observe this in the great oxidability of sulphur and of Cause why phosphorus, combined with the alkalis, or alkaline earths. In sulphur and r r phos. are ren- a combination of two combustible bodies of opposite electro* «ierc! mere chemical natures, this augmentation of combustibility does not combustible , ° , .. 1 bv union with take p.ace, and the combination of the two is less combustible alk. The lat- than that one of the constituents, which was the most so,because ani*r sAilu*.™, I..M* . ELECTRO-CHEMICAL PRINCIPLES, 161 disappearing as caloric, and re-appearing in the electric state restored to the separate elements. If the chemical affinity be nothing more than the result of ^aF^fe"£ the polarity of the particles, it will follow decidedly, that itpiiearenot cannot be affinity which is the first mover, and causes the c^sc:d *T electric phenomena; but that on the contrary, the play of chemi- cal affinities in the pile must be a consequence of these last : And this opinion is accordingly confirmed by experiment.* [Annotation. See remark at the note on page 154.] * I was long of opinion that the oxidation of the zinc in the electric pile, was the cause of the change of electricity, aad I Experiment to endeavoured to prove that this hypothesis was sufficient to ex- ^j™ **' * iC plain the phenomena of the pile (See my Theory of the chemical Electric Pile in the " Neues Allgemeines Journal der Chemie/' fctJVn\°* «. ° bodies do not by Gehlen, in the year I8O7.) But the experiments of Davy produce that and Pfaff, having rendered my opinions less probable, I endea- phenomena. voured to convince myself of the truth, by an experiment which I think decisive. I took 12 tubes of glass, half an inch in diameter and three inches in height, and closed at one end, I half filled them with a strong solution of the submuriate of lime (such as is obtained by the residue after the preparation of caustic ammonia) and above this fluid I poured diluted nitric acid, with the precaution net to mix the liquids. I ranged these tubes in succession, and then took copper wires, round one By a row of of the extremities of each of which I had melted zinc, iu^^madeiu order to attach a knob of that metal to that end. I immersed which the the zinc-coated ends of each into one of the tubes to the bottom pg/^iJ^ ^{J" of the submuriat,and then bended the upper ends of the respec- muriate of tive wires, so as to immerse them into the middle of the acid of llI?f' n,tnc acid ; copper, each nearest tube. This arrangement, consequently, formed a &c While pile in the order following : copper, zinc, submuriate of lime, the, extreme r ° rr ' poles were nitric acid ; copper, zinc, &c. it is evident that the chemical unconnected, affinity which produces oxidation at the common temperature, the nitric acid 1 1 ' r r 1 r , T. . dissolved the was here at the surtace of that part of the copper, which was Cupper,andthe in. contact with the nitric acid ; and that if this oxidation had submuriate been the primary cause of the electricity of the pile, the pole on the zinc. of copper in this construction ought to have possessed the same If oxidation electricity (namely the positive) as the zinc pule in the common 0f positive"^ pile. Before the poles, or extremes, of this small pile were the copper connected, the copper continued to be constantly dissolved in the J'^e been* acid, 362 ELECTRO-CHEMICAL PRINCIPLES. acid, which it turned blue, and the surface of the zinc remained metallic and without any perceptible change. And lastly, I combined the poles by means of silver wires, passed into a tube filled with a solution of muriate of soda. But I was greatly but when the surprised to find the effect directly contrary to what the theory were^olned*16* wl]icl1 consitlers oxidation as the cause of the electiicity of the the action in pile had led me to expect. The solution of the copper instantly butantit re* cease(*and the z,nc became covered with a mass of white oxide, versed. The vegetating on all sides in the form of wool. The pole of the oxklecPthe1'611 C0PPer produced hydrogen gas as usual, and the zinc pole caus- copper ceased ed an abundant precipitate of muriate of silver. The electric f° db?wh>£°l,ved state- therefore, produced in this case an affinity, which, at the ©nthezincside ordinary temperature of the atmosphere is inactive, and caused was positive as another very active affinity to cease, which was already in operation -, and this could be effected by no other cause than the eTect. was *kat °^ ^ie electricity produced by contact, which occasions the not therefore electric charga of the pile, and disposes the affinities which shall fhe action of ^e Put into *#**'$?• This little electric pile, was very powerful, the ordinary and disengaged so large a quantity of gas, as would not have aSaity been exceeded by 100 pair of plates. But what could be the cause of this ? — I exchanged the submuriate for neutral muriate j Changes in the it then produced a very moderate effect, corresponding with the Ijqmd*. number of pairs j and lastly, I substituted neutral muriate of zinc instead of the muriate of lime, and then the effect was scarcely perceptible, though it continued sufficient to prevent the oxidation of the copper in the nitric acid, and to shew that the conduct or of the zinc pole continued always to be oxided. It appears, therefore, that the activity of the pile depends on the liquid substance, which during the process must change place j and that the most advantageous construction of a pile is copper, zinc, alkaline substance, acid, copper, zinc, &c. The pile will continue active untii the order becomes inverted, that is to say, copper, zinc, acid, alkali, &c. This experiment also proves how necessary it is in every' theory of the pile to attend to the chemical effect which must take place in the liquid. [Here the Annotation ends.] The electricity The connection between chemical affinity and the electric excited in the state, is also such, that upon every occasion wherein the effect of byeaftmirtytCto the electricities, excited by contact, cannot take place, the great distance*, affinity acts only at a distance, infinitely small and impossible :o te ELECTRO-CHEMICAL PRINCIPLES, 163 be determined j but on the contrary, whenever that effect can manifest itself, it acts to very considerable distances, as for instance, in the precipitation of metals upon each other ; and it is very probable, that actions at a distance produced by the electric powers do take place in the bowels of the earth, and contribute not only to the great revolutions of which we find the astonishing vestiges, but likewise to the tranquil formation and decomposition of minerals. From the electrochemical view of nature we also derive a The electro- correction in our notions concerning the principles of acidity. pertje's ^hew The celebrated Lavoisier having found that sulphur, phosphorus, why oxigen charcoal, arsenic, &c. produce acids when combined with oxigen, fj^bodies considered oxigen as the acidifying body. But notwithstanding acids, and with this conclusion is supported by the circumstance that oxigen is ot j6ff * • * the most electronegative of bodies, and the acids are also electro- ought not to negative bodies, bodies were afterwards discovered, possessing be. ?j£lf& »* ° . acidifying the principal characters of acids without containing oxigen j principle, and after the discovery that the saline bases are also oxided bodies as well as the acids, it would be equally incorrect to attribute the acid characters to oxigen, or some of its combina- tions, as to suppose it to be the principle of basidity, or to call it the alkaligenous principle. The electro-chemical explanation in which the combustible and from radical of an acid is already in itsnon-oxided state, electronega- these and other tive towards the radicals of the salifiable bases, being consider- shewn, that it ed along with the experimental determination, that the radicals depends on the of the bases, and of the acids, very often combine in the same rafjjc;iand not proportions in the combustible state, as in the oxided state, upon oxigen, proves that it is to the nature of the radicals, and not to oxigen, ^x-^e ^iVbe that we ought to attribute the nature of the product of oxida- an acid or a tion. In this manner it is that sulphur and potassium combine e" for the most part in the same proportions, in the sulphuret of potassium, in the hydrosulphuret of potassium, in the sulphuret of potash, in the hydrosulphuret of potash, in the sulphite, and in the sulphate of potash ; and it is by no means difficult to observe, that sulphur not oxided, performs the part of an acid, that is to say, of an electronegative constituent in the sulphuret and tno hydrosulphuret of potash. These observations upon sulphur and potassium may be applied to all the other com- bustible Jfr£ ELECTRO-CHEMICAL PRINCIPLES. buftible radicals which possess an opposite electric nature. And from all this it follows that it is the radical itself and not the oxigen which determines whether the oxide shall be an acid or a base. Whether the A great question still remains to be discussed : Whether the electricities » , ... and caloric be e^clnciUes and caloric be matter or merely phenomena ? This matter. question has long been disputed, and will long continue in dis- pute before it shall be decided j which, perhaps, will never be done. At present we must content ourselves with reasoning, though our arguments can at best be considered as the sport of imagination upon interesting objects. Though they \{} by the word matter, we understand a body which mani- do not exhibit - . . . . ... r . ' . _ gravitation, *ests ,ts presence by gravitation, which possesses a certain kind noraggrega- of aggregation, and fills the place of its existence, in such a ' manner as to exclude all other bodies — it will certainly follow, that these problematic beings are not matter. But is it not b^'matter*12* P05S^^e tnat tney should be matter, without possessing these characters -} or are the reasons greater for considering them as The hypothesis phenomena ? — A number of philosophers have considered that light is ,. , , .„ . . , , . , , , oscillation "Snt as tne oscillations in a problematical matter produced by objectionable; luminous bodies ; and this hypothesis owes its origin to the analogy which exists between sound and light. But this oscillating matter has not yet been discovered by chemistry ; and consequently the hypothesis itself cannot be satisfactory, the oscillating because it presupposes a thing of which we cannot find the matter is un- . * * , .. , , , , , . known; existence. But if we even admit that light, and the mechani- cal phenomena which are presented in its motion, can be attributed to a vibration analogous to that which constitutes . sound, this mechanical motion cannot produce the chemical anu mereoscn- ^ ..,. , . ,, ..,<- , lation will not effects of light -, such as the alterations in the form, the aggrega- cxplain the tion, or the composition of bodies -} more especially as we have changes, never discovered that sound could produce any such effects. There is, consequently, some probability that caloric may be matter, and that light and all radiations may consist in modes of propagating that matter. Ma'ter rr.ay It may be demanded whether we can, imagine the existence of aftlnlty an"d " a iria,ter possessing chemical affinities without obeying the laws not gravita- of gravitation. There is certainly no contradiction in this position. We admit tjbe difference between cohesion and gravitation, and ELECTRO-CHEMICAL PRINCIPLES. \65 and we are also led to distinguish the latter from chemical affinity. Some philosophers have sought to prove that caloric possesses weight, though too small to he perceived; but if caloric be even Caloric does supposed to be matter, it is not probable that it should possess no gravi weight, because the property of radiating excludes all the effect of gravitation, and because this matter, if heavy, ought to ac- cumulate without limit in the planetary bodies and at length destroy them. From the relation which exists between caloric and the If electricity electricities, it is clear that what may be true with regard to Condudedt!ut the materiality of one of them, must also be true with regard caloric is also to that of the other. There are, however, a quantity of pheno- matter : mena produced by electricity, which do not admit of explana- tion, without admitting at the same time that electricity is mat- ter. Electricity, for instance, very often detaches every thing But ejectr;cjty which covers the surface of those bodies which conduct it. It, detaches the indeed, passes through conductors without leaving any trace of covenngs of its passage ; but it penetrates non-conductors which oppose its course, and makes a perforation precisely of the same and perforates discription as would have been made by some thing which had hodies ; need of place for its passage. We often observe this when electric jars are broken by an over-charge, or when the electric shock is passed through a number of cards, &c. We may, therefore, at least with some probability, imagine Whence it *p- caloric and the electricities to be matter destitute of gravitation, P.ears probable „. . • . . ,- TT7I , • that caloric but possessing affinity to gravitating bodies. When they are and the elec- not confined by these affinities.they tend to place themselves in tricmes are .,., . . . . rr — 1/0°= — lJOdeg. of Fahrenheit's scale. was exposed to This thermometer was exposed to the cold produced by the cold by the method alluded to, and after some time was examined, th«s method, * and the alcohol when the alcohol was found' to have passed all the marks, partly frozen. an(j was obviously sunk within the ball of the thermometer. A slight degree of discoloration was observable. The ther- mometer was replaced, and examined about five minutes after- wards, when the ball of the thermometer was found broken, and crystals adhered to the fragments. Other portions I next took a glass tube, about 3-10ths of an inch in dia- of the alcohol meter, and sealed at one end j into this I poured alcohol till frozen in a ^ stood in the tube 4-10ths of an inch deep, and then exposed tube* it to the cold, produced as before j after some time it was so completely solid, that on inverting the tube it did not drop, and only a very minute stream was perceived to glide slowly down the inside of the tube j when this stream had reached nearly the middle of the tube, the whole suddenly fell out, and, pitch- ing in a glass, was broken into several pieces, which quickly melted. This experiment was several times repeated, but by allow- ing the alcohol to remain a little longer exposed to the cold, it became so completely solid, that on inverting the tube, not the least portion of fluid could be perceived to separate* from the mass. In order to be as certain as possible of the strength of the alcohol I employed, I again took its specific gravity, and the result corresponded with what I before obtained. These experiments, therefore,. left me no room to doubt that I had frozen alcohol, which, at the temperature of 62°, is of the specific gravity 798. Repetitions of Being appointed to deliver the course of lectures on che- the experi- mistry for the session 1810-11, I had no leisure, at that time., ment" to pursue these experiments. They were resumed, however, in the autumn of 1811. The second experiment was repealed and varied, and solid masses of alcohol of some magnitude ob- tained. FREEZING OF ALCOHOL. 163 tained. Some of these I soldered together, using as a hot bolt, a rod of frozen mercury, and sometimes a straw cooled down to a very low temperature. It now appeared to me to be an object of some importance to ascertain the form of the crystals which this substance assumes. This I found attended with some difficulties, which I did not anticipate, and attempts to overcome them have led to the discovery of some facts which I did not at all expect. The common masses exhibited crystals of different forms ; Xlie alcohol two kinds appeared to predominate, and each was tolerably J?*™?*1] ,nt« distinct hi its kind; but it was not very ea^.y to perceive by strata, what increments or decrements the one could be supposed to pass into the other; a rather casual circumstance, however, explained the source of this variety. Attempting to freeze alcohol by a modification of the general process,- which I con- jectured would yield more regular crystals than the common method, I observed, that before crystallizing, the alcohol separated into three very distinct strata; the uppermost was of a pale, yellowish green, while 'he second was of a very pale yellow colour ; both these strata were very thin ; the last mentioned was rather the thickest ; the lowermost stratum was nearly transparent and colourless, and very greatly exceeded the other two in quantity. After allowing a part of the lower The lower stratum, which I conceived to be the pure alcohol, to freeze, I stratum>or r ' greater part, attempted to pour out the remainder ; but, was prevented by the gave rectan^u- upper strata, which proved to be solidified. The lowermost of !ar Pr,8niatic these two strata bore some marks of crystallization j the upper had none, and proved so firm, as to resist a straw with which I attempted to perforate it, to open a passage for the subla- tent liquid. On removing part of these superior strata, and decanting the remaining fluid, the crystals of the lower stratum appeared very distinctly to be rectangular prisms of equal planes, a few of them on one side of the glass surmounted by quadran- gular pyramids, but most of them by dihedral summits. This experiment I repeated several times, and the results coincided. In order to ascertain whether these phenomena arose from The a'cohol, a decomposition of the a'cohol, or from the separation of fo- had "u-'erei reign substances previously held by it in solution, the pro- no change, ducts of several of these experiments were mingled together in a stoppered matrass ; the whole was then raised to the tern- Vol. XXXIV.— No. J5S. N peratun* J 70 FREEZING OF ALCOHOL. peraluie of about 120 deg. by a water bath of that tempera- tare. The substances forming the different strata united toge- ther, and formed a colourless liquor, which had the specific gravity, and all the other properties of the alcohol from which it was obtained. This experiment was repeated several limes, and the results were uniform, affording sufficient evidence, that the alcohol had not been decomposed by this process, but that the superior strata consisted of foreign substances, which . . it had held in solution. The variety in the form of the crys- tals obtained by former experiments, was, therefore, most likely occasioned by the presence of these foreign substances, a phe- nomenon not uncommon in chemistry. The result of these experiments led me now to perceive, that the assumption that alcohol, prepared by Richter's process, is perfectly pure,-or at most contains only a very minute por- tion of water, is entirely gratuitous. The diluted alcohol of commerce, from which the more concentrated is obtained, is well known to contain dirferent volatile impurities ; and since Richter's process makes no provision for the separation of these, we ought rather to expect still to meet with some portion of them in alcohol prepared in this manner. ~* operties of I next proceeded to examine the properties of the different taacc*!^ &" " sa'ostances into which I bad separated Richter's alcohol -, but the time I had now left for this purpose was too short for mak- ing much^progress in this inquiry j a few only of their habitudes with water, and one with another, were all that I had time to examine ; even these I could examine only imperfectly. The lowermost stratum, or nearly colourless fluid, which 1 have called alcohol, had no flavour, and produced on the or- gan of smell only a sharp pungent sensation. It has the re- markable properly of smoking when exposed to the air, and when diluted with water it differs considerably in taste from common diluted spirit of wine. The pale yellow substance, or second stratum, has a pungent taste, leaving an impression of sweetness. It has a very strong but agreeable smell. When mixed with the alcohol, and diluted with water, it has very much the flavour of the better kinds of highland whisky. It readily dissolves in water, and communicates to that fluid its peculiar flavour. The pale, yellowish green substance, which composes the uppermost FREEZING OF ALCOHOL. }J\ Uppermost stratum, has a strong and very offensive smell, and a very sharp nauseous taste. It dissolves in alcohol, to which it communicates its peculiar flavour j its disagreeable smell is considerably heightened by this combination. It dissolves in water, though less readily than the substance last treated of. The compound, when much diluted and heated, has very much the flavour of the low wine of our lowland distillers, at the time it issues from the still. The two last mentioned substances, or those of which the two upper strata are composed, when mixed together and greatly diluted with water, have very nearly the flavour of alco- hol. They have rather more volatility than water; for when half a solution of them has been distilled over, the distilled part has a much stronger smell than that which remains in the retort. It may be proper to mention, that from the circumstance of my sense of smell having been for some time extremely obtuse, I have been under the necessity of trusting to others for the facts regarding the flavour or these new substances and mix- tures ; from the uniformity of the reports, however, which I have received from different persons, I have no doubt that these facts are correct. Besides that from which I filled the thermometer in the Alcohols of first experiment, I have operated on alcohol of the specific le" strength .. w i L^i i •/• • /- . , frozen with si* gravities 802, 797, and 784 $ the specific gravity of the last milar results. was taken when its temperature was 66 deg. and it is probably the most concentrated that lias ever been obtained. But with alcohol of all these different strengths, the g.neral results were similar. In alcohol obtained from different sources, the pro- portions of the impurities were different, both with regard to the pure alcohol, and to one another, but I have met with none that did not: contain both. From these experiments I think it is ascertained -, 1st. That ths strongest alcohol which we are able to obtain, Recapitula- may be frozen by the method alluded to. tl0n- 2d. That this alcohol contains at least two foreign substances, which are highly volatile, and, so far as is known, can only be separated by freezing. 3d. That it is to those substances that alcohol owes its pe- culiar N2 172 FREEZING OF ALCOHOL. collar flavour, and that, according as the one or other pre- dominates, the flavour of the alcohol is agreeable, or other- wise. Last autumn I resumed this subject, and my attention was chiefly directed to the habitudes of these, impurities with the chemical re-agents. This I found attended with consi- derable difficulties, none of the least of which was to procure a sufficient quantity of these impurities in a separate state. The series of experiments I proposed to myself on this sub- ject have not yet "been completed j but I may remark, that the result of some of those I have made, promises to afford practi- cal hints of considerable importance to those brewers whose products are intended to afford spirituous liquors. From this notice it will be observed, that I have scarcely yet entered on the wide field of inquiry, for cultivation of which, the method alluded to appears to offer so powerful an instru- ment. Alcohol only has been snbjected to experiment ; it was the only liquid which had resisted all attempts to reduce it to the solid state by the abstraction of caloric. If these experiments be correct, we may now pronounce it a general law, to which there is no exception, that all liquids with which we are ac- quainted may be reduced to the solid state by a suitable abstrac- tion of caloric. Whether all gases may be susceptible of re- duction to the solid state, by-abstraction of caloric, remains to be ascertained ; although, as I have mentioned, analogy ren- ders it in the highest degree probable. The examination of the singular substances, which alcohol prepared by Ri teller's process contains, has drawn me aside from the course of experiments I prescribed to myself, and taken up that time which I intended to have devoted to the exa- mination of the effects of cold on the gaseous bodies. Whe- ther I shall proceed to these bodies, or resume the examination of the habitudes of the alcoholic impurities with the re-agents, will much depend on the leisure which I can obtain ; but to whichever of them I may direct my attention, I shall not fail to give the earliest information of the result to the Institute. Annotation. — W. N. Remark upon As Mr. Hutton's experiments and observations and perhaps more FREEZING OF ALCOHOL. \J $ more or less of his method, were communicated to his friends, invention", an- it is to be regretted that he has not described it in this notice • n0l,nccQ\ .^nt i- i 11 i i ii- - • notd-jsciiueJ. which would, at least, have secured him against the preten- sions of those who, from conjecture or otherwise, might per- form the same. Without departing from the respect clue to an inventor, I consider it to be quite allowable for me to make a few remarks in this place, for the gratification of such of my readers as may not be familiar with the general subject. If we except the direct cooling process, by communication Except by with bodies at a lower temperature, and the few instances, if' Jlcre. comn»-i- nu\iti:m, and any, wherein cold can be said to be produced by chemical perhaps coin- union, without change as to the state of aggregation, we can f)ination,there i . i * . -i r . ,. ajra M0 cooling look to no other means oi depressing the temperature of bodies, processes within our knowledge, but such as may be founded upon their k"own, but . v r \ ii r ■ i what arise augmentation ot capacity for heat, when they pass from the from fusion or solid to the fluid, or from the fluid to the gaseous, state. In pacification. the first of these two methods, certain bodies, such as snow fuzing mix^ and salt,- one at least being in the solid state, are mixed and tare, combine ; and if the combination be not congealable at (or its freezing point be lower than) the heat of the surrounding or neighbouring bodies, the compound will be fluid, and will take from those bodies all that heat which its increased capacity as a fluid demands, for the maintenance, of that state ; and con- sequently those bodies will be cooled, — and one limit of this process will be at the freezing point of the compound, b*low which it cannot go ; though from the heat of the surrounding bodies, it may be prevented from arriving at that point. But many of the freezing mixtures, at present known, seem which in prac- to have their point of congelation far beneath any temperature SCJUVClv be !;• we can practically look toj and, therefore, a very considerable iftited, but by part of the process of cooling by means of them has been jj* 1^.° " directed to the prevention of the efFect of foreign heat, by first cooling the ingiedients, and surrounding the vessels with other cooling materials. Whether these precautions have been as much varied and applied, as the circumstances appear to de- mand, may, with justice, be doubted. In the second method, by the evaporation of a fluid, such as The- second water in various economical processes, and alcohol and ether metlj<*d !s b7 .ti-ii evaporation; in philosophical experiments, the rapidity with which the ga- seous state is assumed, under like circumstances, governs the result ) 174 TEST FOR ARSENIC. result ; and this rapidity will be prodigiously increased by keep* and probably ing off the surrounding pressure, as in Professor Leslie's expe- to'the's'0"^ rirnent- Whether there be any practical limit of temperature, limit. below which these or all volatile or fluid bodies could be pre- vented from assuming the gaseous state, is, I think, beyond the reach of our inquiries. Freezing pro- These cursory remarks upon cooling1 processes, may lead us cesses may be ... , - . . -- rT . improved by to infer, in the way of conjecture, that Mr. Hutton s process discovery or may consist in the discovery or use of one of the most powerful selection of a . . . . . . a r iU freezing mix- freezing mixtures, and preventing the influence oi the sur- ture, and rounding heat by a judicious application of the means similar to theexiraneons lnose pursued by Walker ; — or, much rather, that instead of heat, this last, he may have applied Professor Leslie's process as to ker's^o/ Les" tue externa^ cooling, by evaporation of ether in vacuo, to a lie's method, vessel containing his freezing mixture. The apparatus for doing this, or for effecting his purpose otherwise, would de- mand a display of skill which we may reasonably expect will add to the philosophical reputation of Mr. Hutton. III. Some Remarks on the Use of Nitrate of Silver, for the Detec- tion of minute Portions of Arsenic, By Alex. Marcet, M. D. F. R. S.* Test fo de- TT^ tne interesting account of the poisonous effects of arsenic, tecting arse- JL presented to the Society by Dr. Roget, and published in the nic; viz solu- stconci volume of the Medico-Chirurgical Transactions!, the tions of ammo- . . nia, and of ni- author has recommended, for the detection of this poison, a **£?& .fr* test which I pointed out to him, and which, from a variety of added by alte- r , , . , , . , . J . ations. experiments, which we tried together, with a view to ascertain "• Read to the Medical and Chirurgical Society of London, in De- cember last, and by them published. It is here inserted, not only on account of its intrinsic value, but because it bears reference to Mr. Sylvester's paper in our thirty-third volume. — N. f I take this opportunity of stating, at Dr. Roget's request, that the patient, whose case he there related, completely recovered her health, and has remained well ever since. its \ TEST FOR ARSENIC. 175 its comparative meiits, we were induced to consider as the most effectual of all the te>ts hitherto used for that purpose. The method consists simply in adding, in succession, to the fluid suspected to contain arsenic, minute quantities of solutions of ammonia and of nitrate of silver ; by which means, if the smallest quantity of arsenic be present, a dense yellow pre- Xe11?w Pre*. . . n J l i • ■•■ cjp. it arsenic cipitate will be produced. be present* All the particular! respecting this mode of detection having been fully stated by Dr. Roget, with such references to former writers on the subject as the case required, it would be quite supeifluous to enter into any further detail on this head. My object in resuming the subject, the practical, importance of which need not be pointed out, is to communicate to the So- ciety the result of an inquiry which I have made on the nature of the yellow precipitate, the appearance of which is assumed as denoting the presence of arsenic, and to answer some objec- tions which have been made against this test by Mr. Sylvester, Objections by of Derby, in a paper on metallic poisons, recently published in l* y vestei- Nicholson's Journal*. The yellow compound in question has the following pro- theOPyeiiow° perties : precipitate. If, after being well washed with distilled water, it be suf- fered to stand for some time in an open vessel, it gradually passes to a brown colour j but it does not, like nitrate of silver, become black on continuing this exposure. It is readily soluble in dilute nitric acid./ It also dissolves on adding an excess of ammonia at the moment of its formation j but after it has been separated and dried, it is no longer sen- sibly soluble in ammonia. If a small quantity of this precipitate be exposed to the heat of a lamp on a slip of laminated platina, a white smoke arises from it, and metallic silver remains attached to the platina.' The reduction of the silver, id the form of a globule, is still more distinct and striking, if a littl- carbonaceous matter be mixed with the precipitate, and the blowpipe applied. When the yellow precipitate, inclosed in a tube, is exposed to the heat of a lamp, the white smoke condenses on the cold; * Nicholson's Journal for December, 1812. Vol. xxxiii. p. 1Q6. part 176 TEST FOR ARSENIC. part of the tube, in minute octoedral crystals of arsenious acid. It is an arte- It appears, therefore, that the precipitate in question is a nite ol silver, combination of white arsenic (arsenious acid) and m!v< »", or an arsenite of silver j and it is inferred that its formation, when ammonia and nitrate of silver are added to a mixture containing arsenious acid, is owing to a double elective decomposition of the arsenite of ammonia, by the nitrate of silver, in conse- quence of which arsenite of silver is formed, and separates as an insoluble precipitate from the nitrate of ammonia which _. . . remains in the solution. The addition of ammonia is neces- Vse and ad- ; / c vantage of the sar>T» because arsenic acid alone cannot decompose nitrate ot ajimonia. silver ; but in Fowler's solution, in which the arsenic is already combined with an alkali, the decomposition takes place at once, without any addition of ammonia. The fixed alkalies, therefore, can answer a similar purpose ; but ammonia lias this advantage, that it does not, wiien added singly, decompose nitrate of silver, a circumstance which, in using the fixed alka- lies, might occasion &ome confusion*. Mr.SylveMer's With regard to Mr. Sylve.^er's objection, 1 shall, previous that muriatic to mJr offering any remarks upon it, state it in his own words. acid would, if " If ever muriatic acid be present," says this gentleman, theTilvcr!€ Z6 '' l^e test *s tnen wn°lty useless, as a muriate of silver will be immediately formed, and the yellow compound, said to be so unequivocal in its indication of arsenic, of course be pre- vented from appearing." This clanger of ambiguity, however, though applying in some degree to the process in question, and well deserving to be noticed, will be found to have been greatly overrated ; and" * It is necessary, as Dr. Roget has observed in the paper already quoted, that the quantity of ammonia should not be too large ; for in that case the precipitate is redissolvcd. But, even then, it may be made to reappear, by the addition of nitric acid in sufficient quan- tity to saturate the alkali. In this case, however, the precipitate is not permanent, owing-) I find, to its being soluble in the nitrate of am- monia which is formed in the process. Carbonate of ammonia has also the propei ty of producing and redissolving the precipitate. The fixed alkalies in excess have not the power of redissolving the precipitate. there TEST FOR ARSENIC. 177 there are such easy and obvious means by which this ambi- guity can be entirely removed, that it can make no solid ob- jection to the utility of the test. There cannot be the le art doubt, as Mr. S. observes, but Remedy. To • • "will rill OX.C(*SS that whenever nitrate of silver is added to a solution containing of ni,rate 0f muria'i;: acid, a precipitate of muriate of silver must be the silver; which consequence. But if the nitrate of silver be added in excess, J[w„ '^ ar- the arsenite of silver is also thrown down by the intervention seme, of ammonia, and a mixed precipitate of luna cornea and arse- nite of silver is obtained, which partakes more or less of the yellow colour of the latter, according to the proportion of the two salts. If to this dubious precipitate a few drops of dilute nitric and the arse- acid be added, the arsenite of silver is instantly dissolved, and ™*e. £e **kuo the muriate of silver, which is insoluble, immediately resumes up by ail. ni- its peculiar density and whiteness. If a little ammonia be now ?"c acld' and r } then precip. added to the clear fluid, the yellow precipitate appeal s in the yellow by am* most distinct manner, and becomes even more characteristic monia« from a comparison with the white precipitate, the appearance of which differs from this in every respect. By this method, I believe that every objection to the test will be removed ; and in order to anticipate all ambiguity, and to avoid any complication or practical difficulty in its applica- tion, I would propose to modify the process in the following manner : To the suspected fluid, previously filtered, add, first, a little Easy manipu- dilute nitric acid, and, afterwards, nitrate of silver, till it shall las^proces*!!" cease to produce any precipitate. The muriatic acid being thus removed, whilst the arsenious acid (if any, and in what- ever state,) remains in the fluid, the addition of ammonia will instantly produce the yellow precipitate in its characteristic form. It is hardly necessary to add, that the quantity of am- monia must be sufficient to saturate any excess of nitric acid which the solution may contain. j;s METEOROLOGICAL JOURNAL. JV. METEOROLOGICAL JOURNAL. B AROMETER. Thermometer. J812. Wind Max. i Mm. Med. Max. Mia. Med. :\ap. Rain 12th Mo Dec. 25 N 3046 3040 30 430' 35 31 33 0 ( 20 N 30-50 30*40 30450; 37 30 33-5 2/ N 30-52 30 48 30 500| 36 29 325 1 28 W 30 52 30*32 30-4201 43 32 37*5 29 W 30 32 30'i5 30*235 46 42 44*0 30 w 3015 29*92 30 035 50 42 460 31 w 29-81 2975 29-780 44 40 420 1813. 1st Mo. 1 Jan. 1 w 3009 29-8] 29-950' 45 38 41*5 2 s w 3020' 30-09 30' 175! 44 36 40 0 6 a 3 w 30 301 30-20' 30 280 41 34 37-5 4 S E 3030: 30*09 30- 1 95 42 34 380 5 S W 3009, 29-86 29-975 44 37 405 5 6 s w 2977 297O 29735 50 40 45-0 9 I 7 N W 2970 29 30 29*500 46 40 430 8 N W 29-621 29-30 29460 48 28 38*0 9 N VV 29 8? 29-75 298IO 4i 31 36 0 9 9 10 N W 29'82, 2970 29*760 34 28 310 ii S E 29 so 2970 29750 40 26 33*0 12 S E 2970| 2901 29,6551 34 29 31-5 13 S E 29 58j 29 53 29-555 38 34 360 5 016 H 14 N E 29-74 29-53 29*635 38 33 35*5 15 N W 3000; 2974 29 870' 38 28 33 0 16 E 3020 3000 30' 100; 44 29 365 17 S E 30" 201 30 04 3012U 35 28 315 18 S E 3014! 30 04 30 090 31 30 30*5 19 20 E 3026 30-141 30 200' 33 31 32*0 ' N E 3027 30 26 30-265 34 30 320 21 N E 3035J 30 27J 30310 34 29' 315 22 N W 30 50 30 35 30425 36 23 295 15 025 0*61 ~ 3052 2930| 30 022 50 23 36 25 The observations in each line 01 the table apply to a period of twenty 4bur hours, bc^inniu^ at 9 A. M. on the day indicated ia the tirst column. A dash denotes, that the result is included in the next following observation. METEOROLOGICAL JOURNAL. 179 REMARKS. 1812. Twelfth Month. 25. A very slight fall of snow. 27. A little snow last night. 30. 31. Windy night : small rain at intervals. 1813. First Month. 1. Small rain at intervals. 3. Misty morning. 5. Windy. 6. Windy: small rain. 7. Very misty, a. m. dark and cloudy, p. m. About 8, some lightning, which was soon followed by a shower. 9. Hoar frost : at 9, a. m. thick air, with Cirrostratus and Cirrocumulus : sounds come freely from the city, with the wind at S. S. W. Sleet and rain followed within an hoar. 13. Overcast, a. m. thin sleet arid lain. 14. Cloudy. \g. A little snow, a.m. 22. Clear, p. ai. A fine red burst in the horizon at sun-set. RESULTS. • Winds variable. Barometer : greatest observed height, 30'52 in. ; least 29*3Q ia. Mean of the period 30*022 inches. Thermometer : greatest height 50° ; least 23°. Mean of the period, 36,025. Evaporation 0*36 inches. Rain and snow 0*51 inches. Plaistow, L, HOWARD. First Month, 23, 1813. }$0 EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. V. On the Explosive Compound of Chlorine and Azote. By Messrs. R. Porrett, jun. Wm. Wilson, and Rupert Kiuk. To Mr. Nicholson. SIR, IJSJSmS 1[H the beSinnin* of December, 1812, we learned from * of JL sc tlie authors* of iL some of the newspapers, and from other sources, that a com* o"u°dVf new exi^os've compound had been discovered at Cambridge, chlorine and by Mr. Burton ; that it was supposed to be a compound of azote. chlorine and azote j that its explosive properties were of the most terrible kind, and had occasioned a very serious accident to Sir H. Davy, who was examining it j that the contact of oil would cause it to explode ; that it was formed by exposing a solution of nitrate of ammonia to chlorine gas; and lastly, that the application of a freezing mixture during its formation was advantageous. Such is the sum of the information which we then obtained, and which stimulated us to undertake a number of experi- ments with this compound j we have not since procured any further information respecting it, excepting such as we have derived from our own experiments. We state this, in order that your readers may have the means of distinguishing from among our experiments, those few which are not original. Experiments. We shall now proceed to relate our experiments, beginning with those which concern the formation of the compound. Chlorine gas The' mode which we adopted for forming it, was, in every was received jnstance, to fill with chlorine gas, over warm water, glass over warm ,-'-■+•% r , . • , , water, in receivers of the capacity of about sixteen cubic inches j and to glasses of 16 transfer" these into small basins, containing the ammoniacal cub. inches, . . „r . . . . , , and thence saline solutions. We soon found that the compound could transferred to De formed with solutions of other ammoniacal salts besides the of the am- nitrate : those which we have successfully employed for ob« mon-solutions. taining it, are the following : Other amnion. Sulphate of ammonia, salts which _, , . , form tlie com- Phosphate ^ do. pound. Muriate * do. Nitrate do. Oxalate EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. 181 Oxalate of ammonia, Muriate of zinc, with excess of ammonia, Muriate of ammonia, and iron by sublimation. Those with which we did not succeed in forming it are the Others which , :. . did not. undermentioned. Carbonate of ammonia, Triple muriate of platina and ammonia, Sulphate of copper, with excess of ammonia. We wished to ascertain whether any other solution contain- Nor did m- . i , • , r * , ■ r -1 trate °» lead? ing azote might be substituted for the solution of ammoniacal at tj,e mjnj_ salt. The solution which we tried with this view was one of mum. nitrate of lead at a minimum, but we could not obtain by its means any of the explosive compound. We have not yet made any other experiments of this nature. There are certain bodies which, if present during the pro- Sulphur, char- cess for forming the explosive compound, prevent its formation, atmoS. ai'r ' or at least prevent it from appearing. Of this description of and hidrog. bodies we have observed the following : §** compound Sulphur, in solution in the ammonia, being formed. Do. in powder within the receiver, Charcoal in fine powder, adhering to the inte- rior moist surface of the receiver, Carbonic acid gas, equal in volume to one- third the chlorine gas, Atmospheric air, do. do. Hidrogen gas, equal in volume to the chlorine gas. With respect to the temperature best adapted for the forma- It is not form- tion of the compound,*our experiments lead us to quite an op- ^r^ ^lo w*" posite conclusion from what has been published. The em- the freezing ploy men t of a freezing mixture, instead of being advanta- P01ntot water: geous, we have found to be the reverse,, as we have never succeeded in obtaining the compound when the solution and the gas were at a temperature below 32°. In these instances, a thin crystalline icy film, was observed to line the sides of that part of the receiver containing the gas, and unless this was dissolved again by raising the temperature, no explosive com- pound was produced. On the contrary, when we have em- ployed solutions of ammoniacal salts at the temperature of 900, h^hrTLmne- the explosive compound has been abundantly and quickly ratures. formed. 182 EXi*LOIIVE COMPOUND OF CHLORINE AND AZOTE. formed. In one experiment we heated the solution to 180', and observed, in ten minutes after, when about half the gas Beautiful eft was absorbed, and the temperature had lowered to 125°, that t at 1^5 (ne recejver above the fluid was covered with the explosive compound, which trickled down to the surface of the solution in minute globules, which converged from all parts of the cir- cumference of the circle forming the surface of the solution to the centre of that circle where they accumulated into larger globules. This phenomenon, which had a very beautiful ap- pearance, seemed to us to be owing to a distillation of the compound from the central or hottest part, and a condensation which ceased at the exterior or coldest part of the receiver. This distillation at iioUe-j. ceased when the temperature had lowered to 1 10°, anu^the ex- plosive compound then formed a film on the surface of the solution. The phenomena attending the formation of the compound, are the following : Phenomena of As soon as the receiver of chlorine gas is placed in the so- ofMhe'eom-0" ^utlon °f tne ammoniacal salt, an absorption of the gas com- pound, mences, and the solution rises slowly in the receiver. An ac- tion is apparent on the surface of the solution, which resembles small filaments reaching to the'depth of about one-tenth of an inch. These filaments, on close inspection, appear to be com- posed of extremely minute bubbles of gas, ranged in a line Absorption of one above another to the surface. When about one-fourth of e^the^ou'-11 l*ie gas has ^lsnPPeared> some or~ tne explosive compound may pound seen generally be observed on the surface of the solution in a thin after one- fljm tjie surface tnen looks oily, and appears divided, so as to fourth of .cas . ', . . ,,...,■ has been ab- give the idea of a map. As the solution rises in the receiver, sorbed. the quantity of the explosive compound increases ; and it then Globules of collects into one or two flattened globules, which when they which pnt-Tr^ beccfcftfe very bulky, fall through the solution to the bottom. and sink. The whole of the gas is absorbed. The solution, after the formation of the compound, contains free muriatic acid, and also some of the compound in solution, if we may judge from its smell and yellow colour. We are not aware, that there are any other appearances during the formation of the compound, which are material to notice. Theory. The following appears, from our experiments, to be the theory of the formation of the explosive compound. When B .PLOSIVE COMPOUND OF CHLORINE AND AZOTE. 18 3 When an aqueous solution of muriate of ammonia is brought Part of ihe into contact with pure chlorine gas, one part of the chlorine ^^"^^ is dissolved in the solution, and there decomposes the ammonia acid with the of the salt, by combining with its hydrogen, (with which it [^!^"nonia, forms muriatic acid,) and sets free its azote, to combine with and part forma another part of the chlorine, with which it forms the explosive the impound 1 • ; with its azote, compound. The compound which is at first formed in this The com- manner, is not visible because it is soluble in chlorine gas, and Poun(1 »e'nrr ° soluble m the there is at first an excess of that present j but in proportion as j»a8, js not the quantity of this gas diminishes by combining with the ele- vtsibfe toll 1 . * 6 . , . 7 5, , much or the ments ot the ammonia, the explosive compound appears, and when solutions of any other salt, formed of an incombustible niacal salts. acid and of ammon^, are employed j the nature of the incom- bustible acid (with the exception of the carbonic) being of no importance, the only use of the acid being to prevent, by en- gaging the ammonia, the rapid action which the chlorine gas would exert on that alkali in an uncombiued state : the exist- ence of it in that state would also be incompatible with that of the explosive compound. This last assertion may appear ex- traordinary to those who know that the explosive compound may be formed by confining chlorine gas over a solution of pure ammonia 5 but it is nevertheless true ; for in this case the ex- plosive compound, although apparently formed from pure am- monia, s in fact, formed from the muriate of that alkali j whic^ J 84 EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. which muriate is one of the products of the exposure of pure ammonia to chlorine gas. The results Two different results are obtained from the mutual action of tlifFcr with the chlorine and ammonia, depending: on the proportions of the . proportions. ... , , . ^, , , if the free tvvo bodies presented to each other. llius, when the quantity ammonia be Gf ammonia present in a free state, is more than the chlorine in excess, r.m- . , ,. , , , r , . . . nate of am- Sas can decompose and neutralize, the whole of the chlorine nionia only is gns gOCS to the formation of muriate of ammonia, and no ex- azote set See. P^os've compound is formeJ, but in its stead azotic gas is fennd at the termination of the experiment, equal in volume to one- third of that of the chlorine gas employed. Thus the only products of the experiment, under these circumstances, are the muriatic acid of the muriate of ammonia, and the azotic gas. But when the But when the quantity of chlorine gas present is more chlorine Raa than is necessary to brine the ammonia to a neutral state : or, is in excess, J ° the last-men- •which is still better, when the ammonia has been previously tioned azote is neutralized by an acid, the azote, instead of remaining after employed in . . . „ . r \ . , 7 , . forming the the experiment in a state of gas, is found combined with the compound. superabundant chlorine, forming the explosive compound. Thus the products of the experiment, conducted in this way, are, the muriatic acid which remains in the solution, and the explosive compound. In the case first stated, the chlorine combines with one of the elements of the ammonia only, viz. the hidrogen ; in that last described, it combines with both, viz. the hidrogen a:, 1 the azote. Experiment ^e sna^ ^ere re^ate an experiment made with the intention on the pro- of ascertaining the proportions of chlorine and "azotic gases, portions. which, in a condensed state, form the explosive compound. The com- Two globules of the explosive compound produced from pound was enual quantities of chlorine gas, and apparently of the same decomposed i . i ,,, i i- i i • by potash and size, were decomposed ; the one by potash dissolved in water, also hy am- the other by solution of pure ammonia; the gases from each were collected and measured ; that from the first was 0*8 of a cubic inch, and that from the last IT. Phosphorus was heated in both j in that produced over the solution of potash it burnt, and caused its volume to diminish to 0 66; in that produced over the solution of ammonia, it did not burn, and caused its volume to increase to 1*3, Now, EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. 1 35 Now, if we suppose the two portions of gas, after the action ' of the phosphorus, to be in the same state, i.e. to be phos- phuretied azotic gas, each containing, with respect to their vo- lume, the same proportions of phosphorus, it will not be ne- cessary, for the following calculation, to make any correction for the augmentation in bulk occasioned by the phosphorus j and as the circumstances of temperature and pressure were the same with both, neither will any conections be necessary for those circumstances — we may, therefore, consider the com- parative volumes of azotic gas produced in the two experi- ments, as represented by 66 and 130, and their difference as 64, being the excess of azotic gas produced over the ammoniacal solution. If we multiply this by 3, (the volume of chlo* rine gas necessary to produce 1 part of azotic gas from am- monia) we shall have 1*92, vwhich will represent as gas the quantity of chlorine in one of the globules. And the quantity of azote, brought to the state of gas from the other, being, , .l according to the first experiment, 066, makes the composition Deduction of the explosive compound to be nearly three parts of chlorine that the new gas to one of azotic gas, condensed to a degree which we contained have not yet estimated. three parts We do not state this analysis as deserving much confidence — andone azote it must be frequently repeated before we can put any faith in it ourselves. Our principal motive in describing the above experiment, be- fore we have had an opportunity of repeating it, is to shew an easy and practicable mode of analysing the compound. It may be proper now to describe some of the physical pro- physical pro- perties of the explosive compound. perties of the Its colour is that of bees' wax ; it is very fluid ; it sinks, compound. although with extreme slowness, in a solution of red sulphate Colour like of iron of the specific gravity of 1 '578. Hence we conclude, very flu"-* that it must be of the specific gravity of about 1-6. It disap- sp. grav.i-6; pears after some time, even under the surface of water, or of *°™s .d^H" the solution in which it was formed j but evaporates almost evaporable" ; instantaneously when exposed to the air j it then diffuses its sm^u offensive 7 ' , , , v and noxious, peculiar and penetrating odour through the surrounding atmos- but less so phere, which th.n affects the eyes in a very painful manner, than of chlo- causing them to ihed tears. Its action on the lungs, however, we conceive to be much milder and less prejudicial .than that of Vol. XXXLV.— No, 158. O chlorine 186 EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. chlorine gas, as we have experienced very little inconvenience in this respect from standing close to a solution, from the sur- face of which the compound was diffusing itself into the atmosphere. Very volatile, The volatility of the compound is so great, as to present a kepthui dose considerable obstacle to preserving it j we have, however, vessel. found, that by limiting the quantity of air or of 'fluid which can come into contact with it, and at the same time preventing the escape of vapour by pressure, it can be kept for any length of time. We have accomplished this by introducing the com- pound into small tubes, closed at one end, about nine inches long, being first filled with some of the solution. The com- pound should occupy at least half an inch from the bottom of the tube, and some of the solution should afterwards be taken out to leave room for a little air, and to allow of the open end of the tube being hermetically sealed before the blowpipe. When any of these tubes are afterwards broken, the escape of compressed vapour is so considerable, as to occasion a loud re- port. Difficult to In our first experiments with the explosive compound, we transfer, be- experienced considerable difficulties in transferring it from one cause so vola- r ° tile. vessel to another, as we had no better mode than that of intro- ducing into the solution and under the compound, a small spoon of tinned iron ; the motion which this communicated to the compound often carried it to the surface, where it ex- tended itself and disappeared, by dissolving in the atmosphere. In order to remedy this, and other inconveniences attending on this method, we invented a little instrument which we have found to answer our most sanguine expectations j it is formed of A small instru- a sma^ Slass tube> °^ tne size °f a ^arSe writing quill, open at went or i;lass one end, and closed at the other, in the manner of a test tube, takiniTiip1 the Wltn l^e excePtlon °f a small circular hole in the centre, compound. This tube is to be used as a syringe, the piston of which is to be formed of cotton, wound round a piston rod of wocd or cop- per j by raising or depressing which, the explosive compound may be drawn into, or ejected from, the tube with the greatest facility. The peculiar advantages of this instrument are, its taking up the compound with so small a quantity of the solu- tion, and with so much celerity, and its retaining it when h e tube EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. 187 tube is held in an inclined position, owing to the concave bed in which the compound lies j in short, this instrument com- bines the advantages of a spoon, with that of a common sy- ringe. It is represented with a globule of the compound in it in the following outline — fig. 3, Plate V, where a is the glass tube, b the circular orifice, c the piston and rod, d a globule of the compound. A precaution very necessary to be taken in the use of this instrument is, that it be clean, or at least free from oil, grease, •r any combustible matter, which might, by causing the com- pound to explode, occasion a serious accident. This precaution is also very necessary with respect to all other vessels with which the compound may come into contact. Another general Precautions precaution, which we strongly recommend to those who may pfgjjjf eX" make experiments with this compound, is, to wear a mask on the face, and gloves on the hands. We conceive it also very proper to state, that although the results of upwards of two hundred different experiments which we have made with this compound are in favour of the conclusion, that it will not ex- plode without the contact of a combustible body, or the appli- cation of a temperature exceeding 200° ; yet three explosions have taken place, the causes of which remain unknown to us, as we were not aware of the compound being in contact With any other body than cold water. These explosions were, there- fore, completely unexpected by us ; but fortunately, they did not occasion any accidents of a serious nature. The effects of different temperatures on the compound we Effects of dif- considered as very deserving of investigation, for which reason ferent tcmpe- J . rata res on the we made the following experiments : compound. A globule of the explosive compound was introduced into a It was not small tube filled with water, it immediately fell to the bottom- ^!:ndat The tube, with its contents, was then placed into a mixture of snow and nitric acid, into which a thermometer was also placed. The mercury fell to — 16° j the water in the tube was of course solidified, but the compound retained its fluidity, and was not altered in any respect. A globule of the " compound was introduced into a At 160 deg. it tube, closed at one end, of the form represented in fig. 4, dhSllauon. * O 2 pi. 188 i:\PLOSIVE COMPOUND OP CHLORINE AND AZOTE. pi. V : it was previously filled with the solution from which the compound was formed. CL The globule is represented at a j the bent part of the tube was then placed in a vessel of water, and its open end immersed into a wider tube, also rilled with some of the same solution. The vessel containing the water was then heated. When the temperature approached to lf30°, it began to distil ; at 1 60° the distillation was rapid, the compound being con- verted to vapour in the bent tube, which served as a retort, and was condensed and collected in that which was disposed as a receiver — much gas was given out during the process. The double curvature of the retort tube was to prevent any of the compound being floated over by bubbles of gas attaching them- selves to it. This precaution we found was very necessary. It did pot ex~ A globule of the compound covered with water, contained plode at 200 jQ a jjttje Sp00n 0f tinned iron, was with the' spoon introduced into a quantity of water heated to 200°— this temperature was not sufficient to make it explode j it merely occasioned its vapo- rization. B4at it did \}o- The last experiment was repeated, varying only the tempera- lently at 212. ture 0f the water, which, in this instance, was 212° j the com- pound immediately exploded violently. These experiments prove, that the explosive compound does not assume the solid form at — 1 6', that it may be distilled at or below 1600, and does not explode but at a temperature above .200°, suddenly applied. Our next object was to ascertain whether, when the natural pressure of the atmosphere was taken off, or diminished, from the explosive compound, it would still retain the fluid form, or whether it would assume the elastic state — with this view we made the following experiment : Apparatus A tube, 31 inches long, closed at the bottom, had another or exposing tuke Qf sm3\\$t ^ore, t,ut 0f tne same lengthy and open at both ends, EXPLOSIVE COMPOUND OF CHLORINE AND AZOTE. 189 ends, placed within it ; both tubes were then filled with rner- the compound cury, excepting about one-fourth of an inch at the top. This ln a vacuum* one-fourth of an inch was afterwards filled with the follow- ing— 1st. A small glass cup containing the explosive compound covered with a drop of muriate of lime. This cup moved freely within the tube. 2d. Muriate of lime in solution, surrounding and rising above the glass cup. 3d. A glass stopper, ground to the tube, and closing it accu* rately. The inner tube was then raised thirty inches above the level The com- of the mercury in the outer one. The column of mercury in Pount,> when ,, . . u j j j -i i i rm vacuo, aii the inner tube descended seven inches, leaving a column of sumed the twenty-three inches only. These seven inches were occupied state°f by the explosive compound in a state of vapour : -but as a little of it still remained in the cup, not converted to that state, a temperature of about 100Q was applied to it — this caused it to disappear, and the vapour, after cooling, then occupied ano- ther inch, the mercurial column being reduced to twenty-two inches. The tube being now lowered until the mercury within and without it were of the same level, the explosive compound reappeared. There remained, however, seven- eighths of an inch of permanent gas, which an accident pre- vented us from examining j but we are inclined to believe, that this small quantity was produced when, on lowering the tube, the mercury rose into that part which had been occupied by the vapour, and the sides of which had been wetted with the liquid muriate of lime, which, notwithstanding that it was very concentrated, had probably absorbed some of the vapour, as we observed some bubbles of gas rising through the mercury from that portion of the metal which was in contact with the humid surface. We repeated the above experiment in the hope, that by ap- Experiment plying heat sufficient to make the vapour explode, we might, of exploding by this means, analyse the compound. We, therefore, exploded the compound, the vapour by surrounding the glass tube with part of a gun barrel heated nearly to redness j but at the instant of the ex- plosion the tube was shattered. We, however, propose to repeat this experiment with a tube of greater strength We 190 STATICAL BLOW PIPE. We have made a great many more experiments with the explosive compound j but as this communication is already of considerable length, we shall reserve the account of them for the next number of your Journal . We are, Sir, Your most obedient, humble Servants, II. PORRET, Jun. W.WILSON. London, l6th Feb. 1813. RUPERT KIRK. Instruments having fluid packing. Description Bt tLe blow pipe. vi. A Statical Blow Pipe, with Remarks ly C. L. THE mercurial pump of Haskins, described by Desaguliers in his lectures j the water bellows of Hornblower in your 1st vol. octavo j the statical lamp, Edelcrantz, in your 5th volume, together with the gauge to Woulfe's most ingenious apparatus for heating water by waste steam, in your 2nd vol. are among the useful applications of a fluid substituted instead of packing, or leathering, for a moveable piece of the nature of a piston. On the present occasion I send you an application of the same description to a blow pipe which acts upon the principle of the regulating piston in large works. The body of the instrument, BB EE, consists of a cylinder, having another interior cylinder, of rather smaller diameter, securely joined to the outer one, at the lower rim of the for- mer, so that both cylinders are concentric, and both open at top j the edge of the inner cylinder being rather the highest. The outer cylinder is set air-tight in the foot E E, and com- municates wjth the lower space D, which has connection with the mouth tube C, and the blow pipe D, by channels which have no other issue. A is a metallic cylinder, closed at the end A, and open at the other, which is the lower end. The letter C denotes a weight connected with the top of A by an inflexible wire or stem. This weight may be changed for one either greater or less, according to the intended force of the blast which is governed by it. The diameter of the cylinder A is such, that it may be inserted mouth downwards in the space between the other two cylinders j and if mercury be th«n poured into that space to about half its depth, the inter- nal STATICAL BLOW PIPE. ipl nal part of the apparatus will hare no communication with the external air, except through G or F, and the mercury will stand on a level on both sides of A. But if the mouth be ap- plied at G, and air blown in, it will be emitted again at F, with a velocity which will be greater the greater the pressure ; but it will not be in the power of the operator to carry this pres- sure beyond a precise and steady limit. For the first effect will be to depress the mercury within the tube A, and at the same time to elevate the outer column or ring ; and as soon as the difference between the heights of the internal and ex- ternal mercury shall have become equal to that of a column of mercury, having the same base as that of the internal part of A, any farther effort will only cause A to ascend > and as soon as this ascent shall have carried the lower rim nearly to the height of the internal mercury, the air will make its escape through the mercury, by means of a notch made in the rim to determine the place of escape. Chemists will perceive, that though this instrument pos- sesses facility and precision of action, and is rendered a snug portable apparatus by a cylindrical cap which covers the whole by screwing on at EF. j yet in point of invention it cannot claim to differ much from the modern gas holders. You have proved to us, on a former occasion, (Journal, quarto series, H. 35.) that the difference of 4-tenths of an inch of mer- cury was as much as blowing by the mouth can support or maintain ; and this blast is sufficient for all the purposes of mi- neralogy and glass blowing. It may also be noted, that a re- action blow pipe, having a packed piston to re-act in a cylinder, and, I believe, another working piston with a valve and proper fittings in the same cylinder, was made many years ago by the celebrated Ramsden. But his compounded apparatus differs in many respects from the subject of the present description. I am, Sir, • * Your obliged Reader, C. L. VII. 192 APPARATUS FOR DISTILLATION. VII. Description of a simple Apparatus for Distillation. By a Cor» respondent To Mr. Nicholson. SIR, THE number of ingenious and beautiful apnratuses for dis- tillation, and the experiments of pneumatic chemistry, give a splendour to the exhibitions of lectures, r.nd are highly gratifying to the affluent cultivators of science. But the greater part of operative chemists every day feel the expence •which, from its own brittle nature, and the heavy duties imposed upon it, attends the use of glass. To them the simplicity and cheapness of a set of vessels stand among its most desirable properties. I send you a sketch of a combi- nation which has not, I believe, the recommendation of novelty, but' which, fram repeated and habitual use, I have found of such value as leads me to believe you will be disposed to bring it into more public notice. It consists simply of A, a retort fitted into B at the neck E, which may be considered as the only indispensable ground joint. Into the other neck of B the vessel C is fitted like the upper vessel of Nooth's apparatus, hav- ing its neck D closed by a conical stopper, or, if preferred, a tube of safety may be placed ther&, In the operation, the distilled matter, or gas, passes over, and is received, condensed, or ab- sorbed, in B. If the pressure be considerable, part of the liquid in B will rise into C, the included air of which last vessel may raise the stopper D, and partly escape. If there be reason, from the nature of the subject, to ap- prehend, that part of the contents of the retort may boil over ; or if the first products of distillation be required not to pass ?nto B, the common adopter may be used, as shown by the dotted lines F. G. H. I. I am, Sir, Your Constant Reader, A. VIII. ARITHMETICAL COMPUTATIONS, ]$3 VIII. Upon certain ready Processsesfor Computation, supposed to have . leen invented ly the American Boy exhibited in London*, SIR, I SHALL make no apology for troubling you on a subject, Introductory which, though generally esteemed dry and abstruse, has ^"^j^'J" at present acquired, from particular circumstances, considerable boy exhibited interest. There is a boy in town, who is exhibited as a curio- m London, sily, from the facility with which he performs several difficult arithmetical operations. It is pretended that this is a gift, and that he has had no instructions to enable him to do this. Now, Sir, 'as there are easy methods of solving these questions, which are not, I believe, generally known, I shall simply state them to the public, that this matter may, if necessary, be further investigated ; and that this boy may be reduced to what he really is — a very clever boy, but no prodigy. In extracting the cube root where it cpnsists of three figures, In extracting it is well known that the first figure of the root may be obtained ^{j"^ r?0t by a simple inspection of the number of millions, and the last riods, the first figure, by observing the final figure of the number whose root period deter- ■ a J & 6 mines toe first is proposed to be extracted j if then, the middle figure could be figure, and the found, we should have the root. To find this, square the final lastdigitdetcr- ^ c , • i f • i iii- mines the figure of the root so previously obtained 5 multiply this square last figure, by 3, call A the last figure of this product. Now cube the last and the middle r. r , , .. . , . ,. . - , figure is found ngure of the root, substract its penultimate digit from the by a simple penultimate digit of the number given, (adding ten to this process, last, if it be the smaller of the two) call the result B. Then that number, which boin^ multiplied into A, produces a number terminating with the figure B, is the middle figure of the root. An example or two will make it manifest : sup- pose 3/7,933,067 to be proposed; here 7 is the first figure, Example of (as 75 = 3'43, the nearest cube below 377) and 3 is the last figure ; since the cube of 3 cerminates with 7, the last figure of the number. Now to find the middle figure 33X3=27. . A=7, and 33=27, of which the penultimate figure is 5. * From the Morning Chronicle of Feb. 17, last. For some accouut of Zerah Colburn, See our present voL page 5. Now, 194 ARITHMETICAL COMPUTATIONS. Now the penultimate figure of the number is G....6— 2=4 =E. And since 27 (or A)=r4, the last figure of which is 4 or B. The middle figure of root is 2, and root is 723. thTruf ?* °f This rule' 1 should add' becomes ambiguous in all cases where the number proposed terminates with an even digit, or with a 5 j thus, in 41,421,736 A=s3 and B=2. Now, as either 4 x 8=32 or 9 x 8=72, it follows that, ac- cording to the rule, either 4 or 9 might be the middle figure, and either 346 or 396 the root j but as 3Qfj j 3= nearly 400 | % or 64 millions, it appears on inspection of the number proposed, that 346 must be the true answer. No error would, therefore, be produced by this ambiguity. Indeed, the only cases of ambiguity which can deceive, are in numbers terminating with 5. The rule for The rule for the square root differs only in these particulars j sqiare^ltS6 t0 determine A> take the simPle P0wer of tile last figure of not much dif- the root, and instead of 3, multiply by 2. To determine B. iercnt subtract the penultimate figure of the square instead of the cube of the last figure of the root. In all other respects, the two rules exactly agree. In the case of square, there is, how- but the ever, an ambiguity which does not exist in the cube. It hap- ambiguity is pens, that the final figure of a square number gives two figures greater. which may terminate the root 5 as for instance, 43=1 6 and 69=36. If, therefore, a square number terminate with 6, its root may terminate with either 4 or 6, and, therefore, more mistakes will occur in the application of the rule. I believe this coincides with the fact j since the boy makes many more errors in the extraction of the square, than in that of the cube root. Reference to The principles of these rules, and the rules themselves, or a ofPR^mcr' d" • very s*'Snt modification of them, have been known so long Ourmes,pub- ago as the year 1768; in that year, M. Rail ier des Ourmes luhed 45 years published two memoirs on the subject. They are to be found in ago, and con- * j j taining the Pp. 485 and .550 of the fifth volume of " Scavans Etrangers." principles of They are entitled u Methode Nouvdle, &c. or a New Method of these method?. . . ... . . dividing, when the dividend is a multipile of the divisor, and of ex- tracting the roots of perfect powers. See page 550. His method only takes the last figures into account. In the extraction of the higher powers, this is undoubtedly the easier way. The second is, " Methode facile, &c, or an easy Method of discovering all the (t prime ARITHMETICAL COMPUTATIONS. 1Q5 ** prime numlers cofitained in an unlimited series of odd numbers * ' in succession, and at the same time, the simple divisors of " those which are not primes. This latter memoir is probably the method pursued by the boy to find prime numbers, and to resolve numbers into their factors. Of tiie method of M. Rallier, he himself says, " In a word, we do not hesitate to " assert from experiment, that ly this method, in a single day , " and in the way of amusement, computations may be effected, " which by the old methods, would require months of severe " labour." I will only now add this observation. As the above rules depend upon the two or three first, and the two last which are figures of any number, it follows that the change of the inter- ^he^ame^s mediate ones cannot affect the result. If it should have those practised occured to anyone, as it has to me, to have altered anyofhlthehoy>mi? J J J ot easy acqtn- these, and yet to have obtained the true result ; it will, I think, sition by any not be unfair to conclude, that either of these very methods, b°y of taleut* or some similar to them in principle, are those adopted. Let me add, that I have no doubt, but that any clever boy would, in a week's time, learn to apply those given above with the utmost facility. I am, Your's, &c. . A. H. E. [The following is from the same respectable daily Journal of the 18th.] SIR, I agree with your correspondent A. H. E. that the young Remedy for American is a very clever boy, but no prodigy, as one visit to tlie ambiguity, him has convinced me. The ambiguity of the cases A. H. E. mentions, in extracting the cube root, may be readily cleared by any one conversant in figures in a few seconds, by finding B in the common formula for the cube root, which is the cube of the binomial A + B ; namely, A3-f-3A'2B, &c. which is, no doubt, perfectly well known to A. H. E. though to some of your readers, who may be interested in this matter, it may not be so familiar. For such the following directions may be use- ful. The first fig. of the root being known by inspection, take its cube from the millions given, then the remainder being 196 AURORA BOREALIS. being divided by the first two digits (for they will be sufficient) of thrice the square of the said fust figure, will immediately shew which of the ambiguous figures should be taken for the second figure of the root. Thus, if the proposed number be 465,484,375, here the first and last digits of the root are 7 and 5: A=5andB>=5j any odd number, therefore, multiplied by A will give B j but if the cube of 7=343 be taken from 465, and the remainder 122 be divided by 14 (the first two digits of 72X 3) it will be instantly seen that 9 is too great, and 5 is manifestly too little j there only remains 7, therefore, for the second digit of the root. The same method will easily clear the ambiguity when the proposed .cube ends with an even digit. I am, &c. O. nection be ^ween the aurora borea lis and mag- netism. Facts. IX. On the Appearance and Disappearance of the Aurora Borealh, By M. Cotte*. Supposed con- ^CITTHETHER there be any relation or agreement between V v the progressive changes of magnetical variation in a given latitude, and the times at which the aurora borealis appears, or ceases to manifest itself, is a question entitled to discussion. It is proved by observation, 1 . That the declination of the magnetic needle is not con- stant ; that in our latitudes it was easterly before the year one thousand six hundred and sixty-six ; and since that time it has more or less slowly increased to the west. 2. That the phenomenon of the aurora borealis, of which the western part of the atmosphere is also the seat, is seen fre- quently during certain epochas, and very seldom during others. 3. That when this phenomenon appears, it sometimes has an influence on the magnetic needle, so as to produce an irre- gularity of motion, or unsteadiness in the variation of the needle. The same thing sometimes happens in stormy weather, or when much electricity predominates in the atmosphere. It must be remarked, that this influence of the aurora Agitation of the needle. Journal de Physique, lxxiii. borealis AURORA BOREALIS. 197 borealis upon the magnetic needle, does not constantly attend that phenomenon, and that a very feeble aurora borealis has sometimes a more marked influence upon the magnetic needle, than a very brilliant aurora borealis. It likewise happens not unfreqaently, that the latter produces no sensible effect upon the magnetic needle. Upon the preceding facts, besides the question first above stated, I would propose the following : Whether the seat of the aurora borealis, in our latitudes before the year sixteen hundred and sixty-six, when the mag- netic variation was easterly, was likewise in the eastern part of the atmosphere. And whether the times, when the variation is stationary, concur with the times of the disappearance of the aurora borealis ; and those in which the variation of the needle is most rapidly changed, concur with the times of the most fre- quent appearance of the aurora borealis. The want of accurate observations, before sixteen hundred and sixty-six, in both respects, renders the second question , - insoluble. With regard to the first and the third question, the following Minutes of the table affords an outline of the observations which have been d.Istinct _Pe" nous oi ap- made upon the progress of the western declination of the pearance and needle since the year sixteen hundred and sixty-six, and the disappearance greater or less frequency of the appearance of the aurora borealis. borealis, for periods of ten years each. 0 ' Times. From 1666 to 1680 increase 1 30 the aurora borealis 7 1680 to 1689 5 20 13 1689 to 1700 2 J 2 22 1700 to 1710 2 38 59 1710 to 1720 2 10 112 1720 to 1724 stationary ■» - 1724 to 1730 increase 1 25 J — "— 531 - 1730 to 1740 1 5 349 • 1740 to 1750 1 45 84 1750 to 1760 1 15 V nQ observations 176O to 17/0 1 25 > - 1770 to 1780 « • 0 50 the aurora borealis 402 . 1780 to 179O 1 1 (>9 — — 179O to 1800 " O 26) disappearance — — 1800 to I8O9 diminish O 12J nearly total. After l$8 THE CHONDROMETEfc, After submitting these observations, I shall only remark, that the nearly total disappearance of the phenomenon of the auror3 borealis, which has taken place from the year seventeen hun- dred and ninety, to the present time, agrees with the diminution of the westerly variation of the magnetic needle, which like- wise commenced nearly at the same time. The observations contained in this notice, may be considered as the commencement of a series in which those afforded by future observers, will, no doubt, be mof; accurate and extended than what our predecessors have left us. The chondro- meter consists of a small measure for com, &c. Method of measuring, Description of a portable Instrument for ascertaining the quantity of Grain by weight, called the Chondrometer*. IN plate TV. Fig. 2. A B C represents a lever or balance moveable on the fulcrum B and supported by the stand G. The bucket F which in the instrument before me has the capacity of 8f- cubic inches, is to be rilled with grain, and when taken off and the handle turned back, may have its contents regulated by striking over the surface with a cylindrical straight piece, of about one-seventh of the diameter of the measure. The arm B C, carries a division, by means of which the sliding weight E can be set to counterpoise the bucket, and its con- tents at any weight of the latter between twenty-five and seventy-five pounds. It scarcely need be observed, that the quality or product of any kind of grain or flour will, under like circumstances, be better the heavier its weight, and that a portable instrument to ascertain this must afford more accuracy than examination by hand. In the use of the present instrument very little instruction is necessary. The measure is to be filled in the same careful manner as a real bushel, and struck even by the- rule, and not by a flat thin edge, which last would carry off too much of the grain ; and rough grain such as oats or barley, * The instrument, from which the drawing in the plate was taken, was made by Messrs. Page and Ovenden, in the Stmod. should ANIMAL HEAT. 199 should be charged a little heavier, because the proportion of these grains torn up by the striking in so small a vessel exceeds , what happens in those of larger capacity. The charged ™d weighing, measure is then to be hung in its place, and the weight being slided to the proper situation for making a fair counterpoise will indicate on the scale the number of pounds in each bushel of eight gallons. The weights per bushel of the nine following specimens of Weights per ^ » y-w j j bushel of grain, as stated by Messrs. Payne and Ovenden, are as under : several de_ lbs. lbs. lbs. scriptions of per bushel mean weight, 5g *iain' . 53 47 Wheat from 55 to 63 Rye — 50— 56 Barley — 45 — 49 Oats — 35— 42 Pease — 62— 67 Small beans — 60—66 Dutch clover — 65— 71 Canary — 54— 56 Rape — 47— 50 38* 6\\ 63 68 55 4fi§ XI. Further Experiments and Observations on the influence of the Brain on the generation of Animal Heat. By B. C Brodie, F. R. S. IN the Croonian Lecture for the year 1810*, I give an account Former ex- of some experiments, which led me to conclude that the Penments- production of animal heat is very much under the influence of the nervous system. Some circumstances, which I have since met with, illustrate this subject, and seem to confirm the truth of my former conclusions. In an animal, which is under the influence of a poison, that Disturbance of operates by disturbing the functions of the brain, in proportion *ne brain , ...,., • • , - , / impairs the as the sensibility becomes impaired, so is the power of gene- animal heat, rating heat impaired also. If an animal is apparently dead from a poison of this de- which is not restored by * Philos. Trans. 13 1 1, or Philos. Journal XXIX. 559. respiration, scription, £00 ANIMAL HEAT. scription, and the circulation of the blood is afterwards main- tained by means of artificial respiration, the generation of heat is found to be as completely destroyed, as if the head had been actually removed, until the brain Under these circumstances, if the artificial respiration is recovers. ^e^t Up untjj tjie effects 0f tjie p0json cease, as the animal recovers his sensibility, so does be also recover the power of generating heat ; but it is not till the nervous energy is com- pletely restored, that heat is produced in sufficient quantity to counteract the cold of the surrounding atmosphere*. In such cir- In the experiments formerly detailed, as well as in those ctimstances the jnst mentioned, I observed that the blood underwent the usual chemical ,./-,., ,. .,1 , changes from alteration of colour in the two systems of capillary vessels, artificial respi- while carbonic acid was evolved from the lungs at each expira- nsual. tion j and hence I was lead to believe, that the respiratory function was performed nearly as under ordinary circum- stances, and that the usual chemical changes were produced on the blood. It appeared, however, desirable to obtain some more accurate knowledge on this point, and I have, therefore, instituted a series of experiments, for the purpose of ascertain- ing the relative quantities of air consumed in breathing, by animals in a natural state, and by animals in which the brain has ceased to perform its office, and I now have the honour of communicating an account of these experiments to this society. It has been shewn, by Messrs. Allen and Pepys, first,f that every cubic inch of carbonic acid requires exactly a cubic inch of oxygen gas for its formation ; secondly, j that when respi- ration is performed by a warm-blooded animal in atmospheric air, the azote remains unaltered, and the carbonic acid exactly equals, volume for volume, the oxygen gas, which disappears. The watery There is, therefore, reason to believe, that the watery vapour vapour which wnjcj, ebcapes Vvith the air In expiration, is not formed from escapes m res- * r piration, is not the union of hydrogen with oxygen in the lungs, but that it is formed during the process, * The poison employed in this experiment should be the essential oil of almonds, or some other, the effects of which speedily suhside. If the wooiara is employed, so long a time elapses before the poison ceases to exert its influence, that it becomes necessary that the experi- ment should be made in a high temperature, otherwise the great loss of heat which takes place, i-> sufncient to prevent iccoveiy. t Phil. Trans. 1807, Pari II. tPhil. Trans, mca, Part II. Ibiil. 1809, Part IJ. exhaled ANIMAL HEAT. 201 exhaled from the mucous membrane of the mouth and pha- rynx, resembling the watery exhalation which takes place from the peritonaeum, or any other internal surface when ex- posed j and this conclusion appears to be fully confirmed by the experiments of M. Magendie, lately communicated to the National Institute of Paris. These circumstances are of importance in the present com- cjiar,ges jn tjif munication, which they render more simple, as they show, that air tiom res- in order to ascertain the changes produced on the air in respira- {"/Educed* tion, it is only necessary to find the quantity of carbonic acid from the car*- given out from the lungs. This becomes an exact measure of ?™£ ^ the oxygen consumed, and the azote of the air and the watery vapour expired, need not be taken into the account. For the purpose of examining the changes produced on the air, by animals breathing under the different circumstances abovementioned, I contrived the apparatus, which is represented in the annexed Plate. Plate VI. Fig. I . Description of the apparatus. A. Is a wooden stand in which is a circular groove J of an Apparatus, inch in depth, and the same in width. B. Is a bell-glass, the rim of which is received in the circular groove of the wooden stand. In the upper part of the bell- glass is an opening, admitting a tu4>e connected with the blad- der C. D. Is a bottle of elastic gum, having a brass stop-cock E connected with it. F. Is a silver tube, of which one end is adapted to receive* the tube of the stop-cock E, while the other extremity, making a right angle with the rest of the tube, passes through a hole in the wooden stand, and projects into the cavity of the bell- glass, where it makes a second turn, also at a right angle, and becomes of a smaller diameter. In the upright part of the tube is an opening G. The tubes are made perfectly air-tight, where connected m with each other, and with the rest of the apparatus, and the circular groove is filled with quicksilver. The capacity of the bell-glass, allowance being made for the rim, which is received in the groove with the quicksilver, is found to be 502 cubic inches. The capacity of the gum- Vol. XXXIV.— No. 158. P bottle '202 ANIMAL HKAT. bottle is 52 cubic inches, and in the calculations after the ex- periments, two cubic inches have been allowed for the air con- tained in the different tubes, and for the small remains of air in the bladder after being nearly emptied by pressure. % Mode of using the apparatus. Use of the In order to ascertain the quantity of air consumed under apparatus .in ordinary circumstances, the animal was placed on the stand which 3n The" ANIMAL HEAT. 203 The animals employed in these experiments were of the The air exa- same species, and nearly of the same size. Attention to these JJJJ^ /f^o?" circumstances was judged necessary, that the results might be ash over mer- as conclusive as possible. The chemical examination of the cury* air was made by agitating it in a graduated measure over quicksilver, with a watery solution of potash. My friend, Mr. Brande, gave me his assistance in this part of the present m investigation, as he had done on many former occasions. It will be observed, that in estimating the proportion of car* bonic acid, no allowance has been made for that contained in the atmosphoric air j tirst, because the quantity is so small that the omission can occasion no material error 3 and secondly, because the object is to ascertain, not so mucfc the absolute, as the relative, quantities of ca- bonic acid evolved by animals breathing under different circumstances. The experiments which I shall first notice, wor^ rcvacfo C;0 the respiration of animals in a natural state. Experiment 1. Thermometer 65°, barometer hot b Experiment 1. A young rabbit was allowed to remain under the fc^V^tass ^Station during thirty minutes. The respired air at the fetid of this for thirty mi- time was found to contain _i_ of carbonic acid. minutes con- * 0 sumert about It was ascertained, that the rabbit occupied the space of 50 50§ cubic Scinches. ££&£• The capacity of the bell-glass =? 502 cubic inches. That of the gum bottle 52 cubic inches. The air in the tubes and bladder == two cubic inchei. 502 + 52 + 2 — 50 506 Then . =s — = 25*3. 20 20 The rabbit, therefore, in thirty minutes gave out 25*3 cubic inches of carbonic acid, and consumed the same quantity of oxigen gas, which is at the rate of 50"6 in an hour. Exp. 2. Thermometer 65 ", barometer 30* 1 inches. £Xp. 2. A somewhat smaller rabbit was allowed to remain under Another at • .,,,,. rrM • j • ., the rate of 56% the bell-glass during 30 minutes. The respired air contained CUDjc inchei. _!_ of carbonic acid. The animal occupied the space of 48 cubic inchei. 502+52+2 — 48 508 ■■ ' '■ a* «= 28 22. 18 18 P2 The '204 ANIMAL HEAT. The carbonic acid evolved was, therefore, equal to 28'22 cubic inches in half an hour, which is at the rate of 56 44 cubic inches in an hour. Exp. 3. ExP- 3- Thermometer 64", barometer 30*2 inches. Another con- A young rabbit, occupying the space of 48 cubic inches, was •ame quantity a^owe^ t0 remain under the bell-glass during the same pe- 4(f riod as in the two former instances. The respired air contained Tig- of carbonic acid. 502 + 52 + 2 ~ 48 508 3= = 28*22. 18 18 The results of this were, therefore, precisely the same as those of the last experiment. These experiments were made with great care. The ani- mals did not appear to suffer any inconvenience from their confinement, and their temperature was unaltered. The next order of experiments were made for the purpose of ascertaining the quantity of air consumed by animals, in which the circulation of the blood was kept up by means of artificial respiration, after the brain had ceased to perform its functions. Exp. 4, . . Exp 4. Thermometer 65°, barometer not noted, were killed by Having procured two rabbits of the same size and colour, dividing the I divided the spinal marrow in the upper part of the neck of The^eat^r* nne'°f them. An opening was made in the trachea, and the off but the lungs were inflated ai first by means of a small pair of bellows. ciaTres* Nation ^wo 1'gatures were passed round the neck, one in the upper, on the air was and the other in the lower part behind the trachea. The liga- not materially tures were drawn tight, including every thing but the trachea j and the nerves, vessels, and other soft parts between them were divided with a bistoury. Eight minutes after the division of the spinal marrow, the thermometer in the rectum had sunk to 97°. The animal was placed under a bell-glass/ and the lungs were inflated by pressing on the gum-bottle about fifty time* in a minute. When this process had been continued " for thirty minutes, • portion of air was preserved for examina- tion. The heart was found acting regularly, but slowly, the thermometer in the rectum had fallen to gQQ. The second rabbit was killed by dividing. the spinal marrow about the same time when the experiment was begun on the first ANIMAL HEAT. 205 first rabbit. Being in the same temperature, the time was noted when the thermometer in the rectum had fallen to q7°, and it was placed under another bell-glass, that it might be as nearly as possible under the same circumstances with the first rabbit. At the end of 30 minutes, the thermometer in the rectum had fallen from 97 to 91*. The air respired by the first rabbit contained -J^ of carbonic Jfc acid. The bulk of the rabbit was found = 50 cubic inches. 502 + 52 + 2 — 50 506 ,. = — = 20.24. 25 25 20*24 cubic inches of carbonic acid were, therefore, extricated in 30 minutes, which is at the rate of 4048 cubic inches in an hour. The carbonic acid given out in the same space of time was less than in the former experiments ; but it is to be observed, first, that in consequence of the ligatures the extent of the circulation was diminished ; secondly, that in this instance one of the ligatures accidentally slipped, and an ounce of blood was lost in the beginning of the experiment. As it was desirable to avoid any circumstances, which might occasion a difference in the results, in the subsequent experi- ments I employed animals, which had been inoculated with the poison of woorara, or the essential oil of almonds j by which means, while the functions of the brain were completely destroyed, the extent of the circulation was undiminished, and all chance of accidental haemorrhage was avoided. Exp. 5. Thermometer 65°, barometer 298 inches Exp. 5. Two rabbits were procured, each occupying the space of rabbits* were' 45 cubic inches. They were both inoculated with the woo- killed with lara poison. . woorara The r consumption The first rabbit was apparently dead in nine minutes after of oxigen, by the application of the poison : but the heart continued to act. art!fic,a.1 resP1* rr * ration, in one The lungs were inflated for about two minutes, by means of a of them, was pair of bellows, when the thermometer in the rectum was n,ot much le8r than before; but in the * In measuring the heat of the rectum in these experiments, care is necessary that the thermometer should always be introduced to exactly the same distance from the external parts, otherwise no positive conclu- sion can be drawn relative to the loss of heat, as the more internal parts retain their heat longer than the superficial, observed 206 Animal HEAt. other, which observed to stand at 980. The animal was placed under the was not made bell-glass, and artificial respiration was produced by means of cooling was pressure on ihe gum-bottle, as in the last experiment. At the? rather less en(j 0f 30 minutes, a portion of air was preserved for exami- nation. The thermometer in the rectum had fallen to 9I0. the heart still acted with regularity and strength. The second rabbit died in a few minutes after the inocula- tion. The time was rioted when the thermometer in the rec- tum had fallen to 98°, and he was placed under a bell-glass. At the end of 30 minutes, the thermometer in the rectum had fallen to Q2°. The air respired by the first rabbit contained ^ of carbonic acid* 502 + 52 + 2—45 511 ' = — = 25*55 cubic inches of carbonic 20 20 acid evolved in 30 minutes, which is at the rate of 51*1 cubic inches in an hour. Exp* 6. Repe- Exp. 6. Thermometer 66°, barometer 30' I inches, mion with the Two rabbits, each occupying the space of 48 cubic inches, were inoculated with woorara. * In one of them, when apparently dead, the circulation was kept up by means of artificial respiration. He was placed in the apparatus under the bell-glass, and the lungs were inflated from 50 to 60 times in a minute. At this time the thermo- meter in the rectum stood at 97 '. At the end of 35 minutes, a portion of air was preserved for examination. The ther* mometer had now fallen to 9O0. The heart was still acting regularly. The second rabbit was allowed to lie dead. When the ther- mometer in the rectum had fallen to 97% he was placed under another bell-glass. At the end of 35 minutes, the thermo- meter had fallen to 90°'5. The air respired by the first rabbit contained T^ of carbonic acid. 502+2 + 52 — 48 50t -— — — =3175 cubic inches of carbonic 16 16 acid evolved in 35 minutes, which is at the rate of 5443 cubic inches in an hour. Exp. 7. Arab- Exp. 7. Thermometer 60% barometer 30*2 inches. The ANIMAL HEAT. 207 I'he experiment was repeated on a rabbit, which had been bit kI[le,d with ,11 • i .i r , j iiri i essential oil of inoculated with the essential oil of almonds. When be was almonds. Re- placed under the bell-glass, the thermometer in the rectum v.ived by artifi- stood at 96°. In a few minutes he gave signs of sensibility, t-on but the and made efforts to breathe ; but as these efforts were at long cooling was intervals, the artificial respiration was continued. In half an "cted^&c**" hour he breathed spontaneously 40 times in a minute. The thermometer in the rectum had fallen to 9O0. The air being examined, was found to contain TV of carbo- nic acid. The rabbit occupied the space of 47 cubic inches. 502 + 52 -f 2 — 47 509 — -— = — == 28275 cubic inches of carbonic 18 18 acid evolved in 30 minutes, which is at the rate of 56*55 cubic inches in an hour. The animal lay as if in a state of profound sleep. At the end of two hours and twenty minutes, from the time of the poison being applied, the thermometer in the rectum had fallen to 79 > and he was again apparently dead) but the heart still continued acting, though feebly, and its action was kept up for 30 minutes longer by means of artificial breathing, when the thermometer had fallen to JQ. The carbonic acid evolved during these last 30 minutes, amounted to nearly 13 cubic inches. From the precautions with which these experiments were Conclusion, made, I am induced to hope that there can be no material That 'ho'arti- error in their results. They appear to warrant the conclusion, t;0n in anani- that in an animal in which the brain has ceased to exercise its mal> of. which functions, although respiration continues to be performed, and without ac- the circulation of the blood is kept up to the natural standard, tion, will keep although the usual changes in the sensible qualities of the \^t^ and1" blood take place in the two capillary systems, and the same produce the quantity of carbonic acid is formed as under ordinary circum- "n^Vblood* stances ; no heat is generated, and (in consequence of the cold it does not air thrown into the lungs) the animal cools more rapidly than Pro when it does not crack, appears to me to be an otherwise not. effect of the contraction of the glass which prevents the caloric from radiating outward, and forces it to radiate or return into the interior of its substance. It is, no doubt, from this reason, that workmen in glass houses can touch with impfunity, a mass of red hot iron in fusion when plunged in water. Explanation I have asserted, that a single degree of difference of tem- theimometri- perature between the mercury and the rubbed body, is sufficient cal difference, to determine the electric state j but this is not to be understood but with regard to temperatures remote from the two extremes at which the electric power is extinguished. Thus sealing wax at 8°. c. is weakly electrified in mercury at 0°. c. and strongly at 8°. c. and so likewise at 4°. c. it is no longer elec- trified in mercury at 0°. c. but it continues to be so by the stroke in mercury at 18°. c. The same thing is observed in all the other bodies at some differences in their degrees in relation to their specific heat. Silk, for example, at 0 . c. is still electric in mercury at 15°. c. ; it is even so when itself at 4°. c. in mercury at 15°> c. but at 5°. c. it no longer shews any elec- tricity. Experiments IV. After having determined the influence of heat upon the mercury was electric Power when lt radiates from the body rubbed into colder than mercury, I was desirous of seeing whether the same effect would bodymmThed take Place when the heat should Pass from the mercury into effects were the immersed body. A tube of glass, particularly when the much less. temperature * ELECTRIC POWER, 215 temperature of the mercury was from 60°. to 80°. acquired no electricity. The same was observed with glass rods $ these came out, nevertheless, electric, when the temperature of the mercury was no more thnn 40°. or 50°. c. -, but this electricity is so weak and disproportionate to that which takes place when the body is hoi, and tfie nercury cold, that I have always con- sidered it with surprise. In order to conceive the cause of this "■ — owing to ;.• • , _ ; ,,,,,, i -i the variation difference, it will be sufficient that I should observe, that a stick 0f tempera- of glass at 75°. c. requires only two minutes to cool down mre m the , , . , , plunged body through 50°. c. in mercury, at 12°, c. whereas, when the same hein and wool, them to an equal temperature with the mercury, provided they be always kept closed in a bottle of caustic lime. 3. The electricity produced by contact, is always stronger The el. is the greater the interval of temperature between the two bodies Plater, the which touch; yet, if the bodies be heated above 75°. c. and they interval of be applied upon mercury, they acquire no electricity, and do temperature, not resume their power until a little cooled. Vol. XXXIV— No. 158. Q 4. The 18 DRAINING OF LAND. 4. The same is true with regard to the inferior temperature, and those below O . A blow will 5. When bodies have the same temperature as mercury, and produce eloc- tjie conlact produces no electricity, the electric power nay the contacts be excited by means of a smart blow of the body under expe- riment upon the surface of the mercury. This blow is some- times ineffectual when the barometer is low. Here we already see the effect of the barometic pressure upon the electric fluid ; but much more evident proofs will be hereafter shewn. (To be concluded in our next,) are at equal temperature? XIII. Plan of the ground. ♦Method of m Account of the Drainage of a piece of Morass Land, called the Tarn, in the Parish of Clapham, in Yorkshire. By Major B. Hesleden. (Soc. Arts XXX.) riOHE plan fig. 2. pi. V, describes the direction in which the JL principal or main drain, as also the cress drains, were severally carried, and A represents a spring of water, B the main drain, CCC, &c. smaller drains, D a small piece of dry ground. The land consists of about twenly-one acres, and from its being encompassed on all sides by rising ground, the water was observed to spring from the bottom of the hill j consequently, the first drain was taken along its base and boundary of the Tarn, so as to receive the water on its first approach ; the others were taken in the same direction, some of which; near the outward side, were made at the distance from seven to ten yards j but near the centre, at a greater distance, (viz.) ten to fifteen yards from each other, according to the dryness of the land. The principal, as well as the cross drains, were finished in the best possible manner, the bottom of them being inva- riably flagged, or laid with flat stones, (except in a few instances that happened to be firm clay), previous to its being walled on both sides, or soughed, then covered with flat stone, and afterwards filled to the top with earth and sod, which wouid be above the stone from one foot to half a yard in thickness, i This DRAINING OF LAND. 219 This mode of draining, the Major would recommend to be always adopted, provided a sufficient quantity of stone can be procured, even if the expense attending it should be somewhat great, since it evidently must ensure its durability, almost for ever, — when in the ordinary way of draining, without first flagg',no» or laying the bottom with stone, it will in no great space of time give way by undermining the walling, or soughing part, besides being more liable to fill or choke up with earth or sediment. It would also be advisable to adopt (as was done in this instance with good effect) the letting in lots, of a given number of roods each, the cutting, stone- digging, soughing, or walling, &"c. to different workmen } as best calculated to ensure the well finishing and due performance of each work. The draining being completed, covered, sodded, and levelled, Expenses, and the same covered with about three thousand horse loads of lime, and after adopting the greatest economy in the expen- diture of this undertaking, the whole proved nearly as fol- iows : L. s. d. The main drain, cutting and blowing up of the rock, and carrying through the hill of the extent and depth so as to gain a sufficient fall. ..... 92 15 O The cross and other drains in the Tarn. 181 7 O Covering the whole with lime, 91 0 O L365 2 O The value of the land in its improved state., in grass, was Value of the calculated to be worth, for the first two or three' years, from „iyes t§ J/gQ* two pounds ten, to five pounds fifteen shillings per acre ; but per cent. pro- the proprietor has not the least doubt, from his experience in * laying lime upon the surface of land of that description, and i in the same neighbourhood, that from the end of the first three years, it will be worth afterwards, and for some time, (for grazing or fattening of cattle) from three pounds ten, to three pounds fifteen shillings per acre, and, consequently, will pay for the money so expended, at least eighteen or twenty per cent, a 2 xiv. 220 EXPLOSION BY SOLAR * LIGHT* XIV. Respecting the Action of coloured Rays upon a Mixture of oxi- muriatic Gas, and hidrogen Gas. By Mr. Seebeck*. Oximur. gas A MIXTURE of oximuriatic gas and hydrogen gas being and hidrogen J^j^ exposed to the solar light, was suddenly decomposed by lar li«ht • "" Messrs. Gay Lussac and Thenard. (See Recherches Physico- • Chimiques, torn. 2, p. I89.) I repeated this experiment with success by means of the gasses which I had collected over hot but not under water. I afterwards introduced these gasses under a glass C?'cl^Chi vessel of a reddish yellow colour, and in another of a deep light decom- Diue> which I exposed to the solar rays. Under the blue glass poses them the decomposition immediately took place, without, however, much sooner c 1 • j • • .. •*. than red and an^ aPPearar|ce of explosion, and in a minute at most it was neither with terminated, and the glass was filled with water for the most explosion. part Under the red glass, on the contrary, the decomposition took place very slowly. After twenty minutes of exposure to strong solar light, very little water had risen in the glass. This mixture of gas from the red glass was then introduced into the white glass, and exposed to the rays of the sun. No ex- plosion took place 3 but in a few minutes the glass became filled with water. These experiments were frequently re. peated, and always with the same result. * 'translated from Schweigger's Journal of Chemistry, II, 263, by Vogel j from whose article in the Annates de Chiroie, LXXXIl. ;323, I have extracted it.— N. SCIENTIFIC SCIENTIFIC NEWS. 221 SCIENTIFIC NEWS. Geological Society. AT a meeting of this Society, on January I, 1813, (the president in the chair) the reading of Mr. Philips's paper " on the Veins of Cornwall" was concluded. The metalliferous veins of the Herland and Drannack mines run E b N and W b S, and the cross courses run N b W and S b E. The rock or country which they traverse is Schist, in some places so hard as to require being blasted. The width °f most of the metalliferous veins varies from two inches to six inches : whenever exceeding this latter measure, they have been found soon after to divide and pass away in mere strings. A contre or oblique vein traverses- these mines in a direction WbN and E b S, varying in width from one to three feet. Near the surface it was found to abound in blende and iron pyrites, but lower down afforded large quantities of copper ore. Whenever it intersected the metalliferous veins, the place of junction formed one lode for about eight fathoms in length, and three or four in width. The contre was heaved by the cross courses, and these latter, at the place of intersection, are found to be not only enlarged but impregnated with ore. The contents of the cross courses are clay, quartz, or a mixture of both. It was in one of these cross courses, at the place of its junction with one of these metalliferous veins, that the cele- brated deposit of silver was found mingled with galena, with iron pyrites, with bismuth, cobalt, and wolfram ; and these substances were also found in those parts of the vein adjacent to the cross course. Huel Alfred is in immediate contact with the mines just mentioned, and is at present one of the richest and most pro- fitable copper mines that Cornwall can boast of. The great deposit of ore is contained in a contre from nine to twenty-four feet wide, which is considered as the continuation of that in Herland mine. The contre traverses a regular east and west vein, and it is remarkable that the ore, abundant as it is, has hitherto been found only in one mass at the depth of 117 fa- thoms CC2 SCIENTIFIC NEWS. thorns at the point of junction of the contre and of the vein, giving off a branch 1 10 fathoms in length, along the eastern part of the same vein. Another singular circumstance in this mine is, that one of the cross courses is heaved and intersected by an E and \V vein. Since the beginning of 1801, there have been sold about 45,000 tons of copper ore, the produce of Huel Alfred, for the sum of about 350,0001. of which the profit, divided among the adventurers, has amounted to about 120,0001. January \5th. The president in the chair. . A paper by William Cony beare, Esq. M. G. S. " On the ori- gin of a remarkable class of organic impressions occurring in nodules of flint/' was read. This paper, which is chiefly occupied by detailed explanations pf the drawings by which it is accompanied, relates to a class of substances thus characterized by Mr. Parkinson, in the second volume of his work on organic remains. " Small round compressed bodies not exceeding the eighth f* of an inch in their longest diameter, and horizontally disposed '\ are connected by processes nearly of the fineness of a hair, H which pass from different parts of each of these bodies, and " are attached to the surrounding ones j the whole of these f* bodies being thus held in connexion." p. y5. Mr. Parkinson conjectures, that the fofmaton of these bodies has been the work of some polype similar to those by which the common zoophytes have been constructed, and, therefore, classes them among fossil corals of unknown genera. He ob- serves, however, at the same time, that his reason for this arrangement is only a very slight analogy, as the objects in question differ materially from every known zoophyte, recent or fossil. Mr. Conybeare having been so fortunate as to obtain several specimens of this fossil in a much better state of preservation than usual, shews clearly that they occur between the bony plates of a large bivalve shell, the Csirco-pinnite of Walch, and in a similar situation in fragments of a striated shell, one ol the pateliites of Da Costa, which more probably, however, pelor.gs to the genus ostrea. Similar substance.* have also been SCIENTIFIC NEWS. £23 been observed on the surface of a cast of the echinu0. The matter of which these bodies are composed is flint, and they are supposed by Mr. Conybeare to be casts of the cells of some minute parasitical insect inhabiting the substance of the shells of certain species of the testaceous molluscae, and probably deriving hence its nutriment either in whole or in part. The anniversary meeting of the Society for the Election of Officers, &c. was held on Friday, the 5th of February, when the following members were elected. President The Hon. Henry Grey Bennet, M. P. F. R. S. Vice-Presidents. Sir Abraham Hume, Bart. M. P. F. R. and L. S. Robert Ferguson, Esq. F. R. S. Sir Henry Englefield, Bart. F. R. and L. S. John Mac Culloch, M. D. F. L. S. Treasurers. William Hasledine Pepys, Esq. F. R. S. Samuel Woods, Esq. Secretaries. Leonard Horner, Esq. Arthur Aikin Esq. Foreign Secretary. Samuel Solly, Esq. F. R. S. Council. The Council consists of the above officers of the society, and of twelve other ordinary members. Alexander Apsley, Esq. William Blake, Esq. F. R. S. J. G. Children, Esq. F. R. and L. S. Samuel Davis, Esq. F. R. S. James Franck, M. D. G. B. Greenough, Esq. F. R. and L. S. Alexander JafFray, Esq. James Laird, M. D. James 224 SCIENTIFIC NEWS. James Parkinson, Esq. Smithson Tennant, Esq. F. R. S. Henry Wnrburton, Esq. F. R. S. William Hyde Wollaston, M. D. Sec. R. S. Keeper of the Museum and Draughtsman. Mr. Thomas Webster February }gtk. The president in the chair. John Bostock, M. D. and Thomas Stewart Trail, M. D. of Liverpool, were elected members of the society. A paper by John Taylor, Esq. M. a S on the economy of the mines of Cornwall and Devon, was read. The subjects ireated on in this paper are, I. The nature of the agreements between the owner of the soil and the mine-adventurers. 2. The arrangements between the partners, or the mine-ad- venturers themselves, and the system of controul and manage- ment, appointed by them. 3. The mode of employing and paying the miners and workmen in use among the agents of the principal concerns. 4. The purchase of materials for carrying on the under- taking. 5. The sale of the ores from the mine-adventurers to the smelting companies. 1. The regulations of the stannary laws refer only to mines of tin ; hence the search after, and working lodes of copper lead, and other metals, i* left open to sach conditions as the adventurers and the lord of the soil can mutually agree upon. In general, the lord grants a lease for twenty-one years, deter- minable, however, at any time on his part if the mine should not be effectually worked. In return he requires a certain pro- portion, varying according to ciicumstances from an eighth to a thirty-second part of the ore, to be delivered tc him ip a mer- chantable state, or its value in money. He stipulates for a power of inspecting the works at all times, and binds the ad- venturers to maintain and leave, at any determination of the grant, all the shafts, adits, and levels, perfect and in good con- dition as to timbering. 2. The adventurers divide the whole concern into sixty-four shares, SCIENTIFIC NEWS. 265 shares, which they distribute among themselves, and those who are allowed to join them, in various proportions. At the end of every two or three months, a general meeting of the ad- venturers is summoned, a statement of the accounts is laid be- fore them, and the profit or loss is distributed to each, according to the amount of his shares. The general detail of manage- ment is usually delegated to one person, under whom are sub- ordinate managers, called captains, selected among the working miners for their skill and character. 3. The work of the mine*, both on the surface and below ground, is almost universally contracted for by the piece, at a kind of public auction held ;.t the end of every two months j an accurate survey and metsnrement of the whole being pre- viously taken by the captains. The lowest bidder has the set, and, in order to execute it, he associates to himself from one to eleven men, women, or children, according to the nature of the work. An account is then opened between the principal captain and thecontractor^in which this latter is credited with all the tools, candles, gunpowder, and subsistence-money re- quired by himself and his gang during the term ; at the end of which the tools, and articles not u*ed. are returned, the account is balanced, and the gain or loss on the contract is declared to the persons interested. 4. If materials for the use of the mine are purchased from those holders of shares who deal in the articles wanted (as is not unusual) great vigilance is required in the other proprietors to . / check the natural temptations to charge exorbitant prices, or to encouTage a wasteful consumption. 5. The smelting companies for copper have seldom any share in the mines. There are about fif een copper companies, all of which have agents and assay offices in Cornwall, though the smelting itself is carried on at Swansey. A weekly meet- ing is advert zed to be held at some place near the principal mines, where the ores on hand, allotted into suitable parcels, (the produce of one mine being kept separate from that of ano- ther) are offered for sale. Previous to the day of sale, the persons intending to purchase attend at the mines for the purpose of taking samples, which are immediately put into the hands of the assay-masters. The agents for the smelting companies being thus furnished with the requisite information, attend 226 SCIENTIFIC NKW3. attend at the meeting, and each hanJs up to the chairman a note or ticket, containing the price per ton which he is dis- posed to give j the chairman then reads aloud the various offers, and the highest bidder is declared the purchaser. Models of all the most Interesting Parts of the High Peak of Derbyshire. > Mr. ELI AS HALL, Fossilist and P elref action- Worker , of Castleton, near Tideswell, in Derbyshire, has announced, that since the mineral survey of the county of Derby was undertaken for the board of agriculture, by Mr. John Farey, sen. and particularly since the publication of the first volume of his " Report on Derbyshire" by the Board -, Mr. H. has assiduously applied himself to an examination of all the mineral limestone district and its vicinity, to the northward of Winster and Hartington, and to the carving out and completing of a model of its curious and rugged surface, under the patronage of his Grace the present Duke of Devomhire3 and the Right Hon. Sir Joseph Banks, Bart. On exact casts from this model he has contrived (as on Mr. Farey's mineral Maps) to represent, by colours, the eleven lowest of his principal rocks and strata of this district 5 viz. 3, fourth limestone {ochre yellow); — 2, third toadstone (red) ; — 3, third limestone (grey blue) ;-— 4, second toadstone (bright yellow) j — 5, second limes' one (green) 5 — 6, first toadstone (very dark blue) ; — 7, first limestone (grey white) j — 8, lime- stone shale (reddish brown) ;— (), first or millstone grit (yellow) ; — 10, first coal shale (dark brown) -, — and 11, second grit rock (dark broivn). — These several colours being painted on a fillet, in their proper order, by the side of actual specimens taken from the eleven rocks and strata above mentioned, are arranged and fixed on the E. side of the model, interspersed with other speci- mens of the chert, black marble, shale-freestone, coals, entrochi, &c. which belong to such strata. Besides which, the ranges of all the principal mineral veins are represented, on the model, by blue lines for rake veins -, and broad blue lines with yellow dots on them, for pipe veins ; and specimens of lead ore in each limestone rock are given. The SCIENTIFIC NEWS. The great limestone and the MMl faults (of Mr. Farey's Report, Vol. I. pp. 280 and 290,) are represented by a broad red line with black dots on it. The turnpike roads are represented by small elevated lines ; and the towns and villages, by small round elevations. Printed labels are affixed to the several towns, villages, roads, hills, valleys, strata, mineral veins, caverns, &c. The superficial scale of this model is one inch and a quarter to a mile. The scale for heights and depths necessarily exceeds the other, in order to give every lnil and valley as nearly as •possible the appearance that it had on the spots, where the carv- ing was the greater part of it executed. The colours are painted in oil, so as to be permanent, and admit of the model being cleaned from dust, &c. ; and the whole is inclosed in a strong deal box, 20 inches long (from N to S,) 19 inches wide (from E to W,) and three inches deep, with a lid which takes off" when the model is in use, and on the under side of which this description may be pasted and pre- served. For more readily understanding the internal parts of the district represented in the model, it should be observed, that the limestone-stone shale (reddish brown^ occupies all the borders of the model, (but sometimes with first grit and coal shale upon it,) except for about six inches near its bottom, or S. end, between Sheen-Hill and Hartle-Moor : that this scale has an easy dip, or declines gently on the W. N. and E. sides, in those several direc- tions, or with an easy rise towards the limestone and toadstone districts, whose strata have a general and rather a rapid dip towards the E. The four limestone rocks, coloured grey white, green, grey blue, and ochre y ellow , dip successively under the eastern shale, and each other, in this order : and the three toad- stones, coloured dark blue, bright yellow, and red, dip also to the E. between the limestone rocks. The coloured patches and rings will point out the several hummocks and denndated patches of strata, that are detached from the masses or surfaces of the seven strata of limestone and toadstone which are mentioned above. Mr. Hall's own examination of the strata of the considerable district comprised in his model was separately conducted, and afterwards compared with Mr. Farey's report and manuscript map j 227 £28 SCIENTIFIC NEWS. map ; and every spot, wherein any difference of the two surveys appeared, has been visited again and again ; all the old and best- informed miners have been consulted, and by repeated corres- pondence, and the liberal and ready communications of Mr. Farey, he considers himself as warranted to present his models, as faithful representations of the numerous and highly curious phenomena which the High Peak presents j any of which he is ready to explain minutely on the spots, and, in other respects to assist the investigations of curious travellers who may be anxious to examine and verify these facts, and wish to engage his perso- nal assistance for such pujpose. It is also a part of Mr. Hall's professional business to make and label ample specimens of all the various mineral productions of the Peak Hundreds ; care- fully noting their precise localities, and their places in the strata or veins (a species of information too rarely met with, even in the best mineral collections.) He always keeps a large collec- tion of the Derbyshire minerals, for sale, collected almost entire- ly by himself. Mr. Farey, from a desire to promote mineral science, and to serve Mr. Hall, has consented to keep some of his models, at his house, No. 12, Upper Crown street, Westminster, London, for inspection, and sale, at eight guineas each. They may also be had, on these terms, of Mr. Hall himself, as above, or by application to him by letter. Mr. Bakewell will commence a coarse of geological lectures in March, at Willis's rooms, King-street, St. James's, designed to illustrate the geology and mineralogy of England, and particu- larly intended to direct the attention of landed proprietors to the neglected mineral treasures on their own estates. Mr. Bake- well also intends shortly to publish, in 1 Vol. 8vo. a work entitled Outlines of Geology, with observations on the Geology of England. Speaking SCIENTIFIC NEWS* £29 Speaking Automaton or Machine. Mr. Robbrtson, whose name has frequently appeared in the Annales cle Chimie, but Is better known to the public as an aeronaut in Denmark, lias, it is said, contiiveda speaking figure, which he exhibited a few months ago at Paris. ]t articulates the words Papa, Manzma,and Five Napoleon, anddai'y improves in power, from (as may be supposed) the practice of the person who works it. . On this occasion I would remind some-of my readers, who may have remembered the automaton chess player, which was exhibited in St. James's Street, about thirty years ago by the Baron Kempellen, — that that mechanic shewed, in a kind of half private exhibition in his parlour, after the games at chess were over, an instrument which spoke. I was present atone of these performances The Baron said the machine was not then completed. It was a kind of box which he brought out and placed upon a table. Speaking without any memorandums at so considerable a distance of time, I judge its dimensions to have been about two feet in length, one foot wide, and eight or nine inches deep. It had no lid j but we were prevented from seeing the inside by a cloth which covered it. The Baron put his hands into the box under the cloth, so that his right arm was disposed longitudinally in the box, and seemed to pre^s a pair of bellows : the other hand was put in, crosswise at the end, near the place of the right-hand, and seemed to be employ- ed with keys or some apparatus, or perhaps both hands may have been so employed. When he caused the instrument to speak, he raised his right elbow and gradually pressing it down, the sound was heard. It was a clear monotonous sound as if from a single pipe about the pitch of D,, above the middle C, concert pitch ; and the words papa and mamma were uttered, very distinctly in a slow drawlin? manner ; that is to say there was a want of the usual modulation of speaking tones, and the sound fell off in its intensity towards the end. After several other words had been spoken, a lady asked in French if it could not speak sentences, and the Baron asked what it should say : she answered que se suis mechante, and the instrument said vous etes mechante, mats vous etes aussi bonne. Kratzenstein 230 SCIENTIFIC NEWS. Kralzcnstein has given same account of the principles of an engine of this kind in a memoir extracted in the Journal de Physique, and Dr. Young has cursorily mentioned the subject tfl his lectures, with some diagrams. Quantity of Spirits and other fluids ascertained ly Weight. Mrs. Lovr has lately communicated a memoir to the Edin- burgh Institute, upon the advantages in point of accuracy of measuring fluids by weight instead of using vessels of known magnitude. She is mentioned as patentee of the areometricai beads, which have been now upon sale in London for a con- siderable number of years, and consist of small glass balls hermetically scaled, having their specific gravities written upon them. The principal objection to these is their number and brittleness, and, perhaps, the difficulty of making them of so small a size, with as much accuracy as the larger ball, of the usual floating instrument. With regard to the practice recommended of weighing fluids instead of measuring them, it is grounded on the considerations, I. That weights are usually made with more exactness than measures. 2 The measuring multiplies error by aseriesof operations, 3. and it has been questioned whether a single measure of a fluid could be had to the same degree of precision as a mass determined by weight j though by the common figure given to the copper measures which terminate in a neck or throat having a small surface, the precision required in business may, no doubt, be had. — Considerations of temperature affect both methods alike, and I apprehend that, though the temperature of spirits is attended to, in determining their strength, yet it is neglected in taking the measures of quantity j which it is liable to affect as far as 2 per cent, or one gallon in 50, and ought, therefore, to be considered. I have seen oil sold retail by the gallon weight in London, which is certainly very fair for the buyer, who might else in that adhesive fluid, lose as much as hangs to the vessel every time it is emptied. . New SCIENTIFIC NEWS. 331 New Pullications. The Gentleman's Mathematical Companion, for the Year 1813 ; containing answers to the last year's enigmas, &c. &c. Price 2s. 6d. Elements of Universal Geography, ancient and modern ; with historical, classical, and mythological notes. By A. Pic- quet. 12mo. 5s. A Sketch of the Sikhs, a singular nation, who inhabit the provinces of the Penj ah, situated between the rivers Jumna and Indus ; by Sir W. Malcolm, 8vo. 8s. (5d. Asiatic Researches ; or, Transactions of the Society in- stituted in Bengal. Vol. XI. octavo 18s. or quarto two gui- neas. Topographical Dictionary of Yorkshire. By W. Langdale, 8vo. 10s. 6d. The Picture of London for 1813. 6s. 6d. Travels in South America. 4to. 21. 2s. forming vol. XIV of Pinkerton's General Collection of Voyages and Travels. General Collection of Voyages and Travels, Part LVIII.4to. 10s. 6d. Journal of a Residence in India ; by Major Graham. 4to. ll. lls.fjd. boards. Rees's New Cyclopedia. Vol. XXIII. Part I. ll. or large pa- per, ll. 16s. Correct Tide Tables for the Year 1813, shewing the true time of high water in the morning and afternoon of every day in 232 SCIENTIFIC NEWS. in the year, for all the principal ports and places in Europe and America, By William Adams. Is. Sir H. Davy will soon publish Elements of Agricultural Chemistry, in a Course of Lectures delivered before the Board of Agriculture. A new edition of Smeaton's Account of the Building of Edystone Light-house has been announced, and is considerably advanced. Professor Playfair is printing the second part of his Outlines of Natural Philosophy j and also a new edition of his Illus- trations of the Huttonian Theory, Phtlo*. Journaf VH XXXltffl JV.p.2&%. l^^t//s/ •//>■/ y ■ yMateiAe** J^itf./. ;a-.. j Ch on f/rom eter or In stril m en t - examining grain, 6\ weight Fio. Philo*. Journa.1 Vol XXXlVJ>Ur.p28% t ///r // 1 y/ / /■; C0U ■ JuAes frt{ 'c /. — hj^'""' »■ im JOURNAL OP NATURAL PHILOSOPHY, CHEMISTRY, AND THE ARTS. APRIL, 1813. ARTICLE I. Experiments on the comparative Strength of Men and Horses, applicable to the Movement of Machines. By M. Schulze*. THOSE who have had occasion to construct machines in- Importance of tended to be moved by men or animals, are sufficiently forc^oTmen*1 aware how important it is to be acquainted with the quantity and animals as of power that can be attributed to either of them, in order to first movers estimate with accuracy the effect which it is proposed to obtain from the machine. It is well known, that the arrangement of the whole depends entirely on the ratio of the velocity of the motive force to the resistance. This was the reason that long ago induced experimentalists to take the trouble of determining the strength as well as the velocity exerted by men and animals, when they are made to move machinery j and the results they obtained, which have been commonly made use of in comput- ing the effect of machines, are, that men exert from twenty- seven to thirty pounds, with a velocity of from one and a half to two feet per second j and that a horse has about seven times more strength than a man, with a velocity of from four to six feet per second. These are the data which we have been obliged to use when- For aulas of * Memoirs of the Royal Academy of Sciences of Berlin for 1783. Vol. XXXIV.— No. \5(), R These 234 STRENGTH OF MEN AND HORSES. Enler for de- termining the effects of ma- chines moved with diffeient velocities, &c. Experiments with men. Their sizes and weights. ever it became necessary to compute the effect of a machine moved by men or horses. It is evident that the force must be diminished when the velocity is increased, and vice versa : but we are not yet certain of the method of finding the ratio of the diminution or augmentation of this force to the velocity. Euler has given us two different formulae to compute this ratio : but no one has hitherto attempted to verify by experiment which of ihem is to be preferred, although they differ very conside- rably from each other. If we put P for the absolute force which takes place when we simply consider equilibrium, C the absolute velocity which takes place when the man or animal moves freely, and without being overcome by the resistance, p the relative force, and c the corresponding velocity, we hav« by the first of these formulas, 2 j whereas the second gives usp= P (I C\ As I am obliged now more than ever to attend to a number of machines, and to compute their effect, it therefore concerns me very much to know exactly in what manner to estimate, compare, and fix the strength and velocity of men and animals, which are used for moving various machines, proper for diffe- rent purposes. With this view I made, with considerable care, the experi- ments I am now about to detail, which of course would have been very expensive, had I not had some facilities which other persons may not possess. To make the experiments on human strength, I took pro- miscuously twenty men of different sizes and constitutions, whom I measured and weighed 5 the result of which is given in the following table : Wei glit. 0% -) cv Order. Size. Weight. ) 1 0 3'' 4" 122 2 5 2 3 134 3 5 7 2 165 4 5 5 0 131 5 5 11 2 177 6 6 0 4 158 7 5 8 3 180 8 5 2 1 117 9 5 4 8 140 10 5 0 4 126 Order. Size. 11 5< 9" r 12 5 1 4 13 5 3 2 14 5 4 1 15 5 10 8 16 5 0 3 17 4 11 2 18 5 3 9 W 5 6 0 20 5 10 1 132 157 175 192 133 147 124 163 181 STRENGTH OP MEN AND HORSES. 23> To find the strength that each of these men might exert to raise a weight vertically, I made the following experiments : I took various weights, increasing by lOlbs. from 150lbs. Expcri- up to 250lbs. All these weights were of lead, having circular on tjiejr p and equal bases. To use them with success in the proposed strength* experiments, I had at the same time a kind of bench made, in the middle of which was a hole of the same size as the base of my weights : this hole was shut by a circular cover, which effected this purpose when pressed against the bench, but at other times was kept at about the distance of a foot and a half above the bench, by means of a spring and some iron bars. To prevent the weight with which this cover was loaded during the experiment, from forcing down the cover lower than the level of the surface of the bench, I had several grooves made in the four iron bars, which sustained the cover at any height at which it might arrive by the pressure of the springs, as soon as the pressure of* the weight ceased. After having laid the ]50lbs. on the cover, and the other in raising weights in succession, increasing by lOlbs. up to 250lbs. I vphyIShV made the following experiments with the men whose size and weight are given above, by making them lift up the weights as vertically as possible all at once, and by observing the height to which they were able to lift them. The following iable gives the heights observed for the different weights marked at the head of the table. vertically, 150 160 1 7" 9" 6 < 4" s 7 10 6 6 3 7 9 7 3 4 8 3 7 6 5 12 4 11 1 6 14 5 14 0 7 12 11 11 3 8 11 9 10 2 9 9 5 8 3 I? 8 1 6 5 170 180 190 200 4"11"' 4" 4" 3" 8'" t" 8'" 5 7 4 7 3 11 2 5 6 5 5 9 4 11 4 0 7 2 0 10 5 3 4 7 9 7 8 5 7 10 7 1 13 5 12 8 11 S 10 1 10 5 9 3 8 1 6 9 9 4 8 11 8 1 6 11 7 1 5 6 4 T 2 9 4 7 3 9 2 5 1 7 210 1" 1" 0 5 3 0 4 0 5 10 8 G 5 3 5 10 1 3 0 4 220 230 240 1" 7"' o" 5" a 8 9 I 1'' 4" 4 7 3 2 1 3 6 6 4 1 0 1 .3 8 1 11 0 2 5 1 3 2 1 0 This table proves to us, that the size of the men employed Results, to raise the weights vertically, has considerable influence on the height to which they severally brought the same weight. We find also by this, that the height diminishes in a much mor© R 2 con- VJb STRENGTH OF MEN AND HORSES. considerable ratio than the weight increases j and we may therefore conclude, that it is advantageous to employ large men when it becomes necessary to draw vertically from below upwards j and, on the contrary, it is more advantageous to em- ploy men of considerable weight, when it is required to lift up loads by means of a pulley, about which a cord passes, which the workmen draw in a vertical direction, from above downwards. To find the absolute strength of these men in a horizontal direction, I took the following method : Having fixed over an open pit a brass pulley, extremely well made, of fifteen inches diameter, whose axis, made of well- polished steel, to diminish the friction, was three-fourths of an inch in diameter ; I passed over this pulley a silk cord worked with care, to give it both the necessary strength and flexibility. One of the ends of this cord carried a hook to hang a weight to it, which hung vertically in the pit, whilst the other end was held by one of the twenty men, who, in the first order of the following experiments, made it pass above his shoulders j in- stead of which, in the second, he simply held it by his hands. I had taken the precaution to construct this in such a manner, that the pulley might be raised or lowered at pleasure, in order to keep the end of the cord held by the man always in a hori- zontal direction, according as the man was tall or short, and exerted his strength in any given direction. I had made the necessary arrangements, so as to be able to load successively the basin of a balance which I had attached to the hook at the end of the cord which descended into the pit, whilst the man who held the other end of the cord em- ployed all his strength without advancing or retracting a single inch. Experiments The following table gives the weights placed in the basin with men put- wjien tjie workmen were obliged to give up, having no longer ling horizon- . ° & r . V . , tally. sufficient strength to sustain the pressure occasioned by the weight. To proceed with certainty, I increased the weight each time by five pounds, beginning from 60, and intervals of time, having always precisely *a space often seconds between them. The result of these observations, repeated several days in succession, is contained in the following table : When STRENGTH OP MEN AND HORSES. 237 When the cord passed over the shoulders of the workmen : Order. lbs. Order. lhs. I Orrfpr. lhs. Order. lbs. 95 105 110 100 105 Order. lbs. 6 100 7 115 8 105 9 95 10 90 Order. lbs. Order. 11 95 16 12 100 17 13 110 18 14 90 19 15 110 20 95 100 90 110 105 When the cord was simply held before the man : Order. lbs. Order. lbs. ! Order. lbs. Order. lbs. 90 6 100 11 90 16 90 105 7 110 12 90 17 90 105 8 100 13 100 18 85 90 9 90 14 85 19 100 95 10 85 15 105 20 100 1 2 3 4 5 These two tables show, that men have less power in drawing Results. a cord before them than when they make it pass over their shoulders : it shows us also that the largest men have not also the greatest strength to hold, or to draw in a horizontal direction by means of a cord. To obtain the absolute velocity of these twenty men, I proceeded as follows : Having measured very exactly a distance of 12,000 Rhin- Marching of land feet, in a plain nearly level, I caused these twenty men to m<;n ^°11' ,con* , , . , . , siderable march with a good pace, but without running, and so as to times. continue during the space of four or five hours. The following is the time employed in describing this space, with the velocity resulting from each of them. •d. Time. Veloc. 1 40' 18 4' 94 0 41 12 4 85 3 39 8 5 55 4 39 40 5 04 5 34 ic: 5 83 (i 95 11 5 68 7 38 7 5 25 )rd. Time. Veloc. Ord. 15 Time. Veloc. 8 40' 9 4' 99 36' 17,5' 51 9 40 20 4 96 16 41 2814 82 10 40 51 4 90 17 42 25 4 71 11 36 17 5 51 18 40 19 4 98 12 38 11 5 24 19 39 57 5 01 13 38 5 5 25 20 37 51 5 29 14 37 1 5 40 It is necessary to mention, with regard to these experiments, that I took care to place, at certain distances, persons in whom I could place confidence, in order to observe whether these men marched uniformly and sufficiently quick without run- ning. Haviog 23S STRENGTH OF MEN AND HORSES. against the men. Having thus ohtained, not only the absolute force, but the abso- lute velocity also, of several men, I took the following method to determine their relative force. The same with I had made use of a machine composed of two large cylin- mtemnce ^ers °*" ve,7 narc* marble, which turned round a vertical cylin- der of wood, and moved by a horse, which described in its march a circle of ten Rhinland feet. This machine appeared to me the most proper to make the followi-ng experiments, which serve to determine the relative strength that the men had employed to move this machine, and which I use hereafter to determine which of Euler's two formulas ought to be pre- ferred. ' To obtain this relative force, I took here the same pulley which served me in the preceding experiments, by applying a cord to the vertical cylinder of wood, and attaching to the other end of this cord, which entered into an open pit, a suffi- cient weight to give successively to the machine different velo- cities. Having applied in this manner a weight of 215lbs. the machine acquired a motion which, after being reduced to an uniform motion, taking into .account the acceleration of the weight of the friction, and of the stiffness of the cord, gave 2*41 feet velocity 3 and having applied in the same manner a weight of 220lbs. the resulting uniform motion gave a velo- city of 2'47 feet. I only mention these two limits, because they serve as a comparison with what immediately follows. I began these experiments with a weight of lOOlbs. and in- creased it by five every time, from that number up to 400lbs. I made this machine move by the seven first of my work- men, placing them in such a way, that their direction remained almost always perpendicular to the arm on which was attached the cord which passed over their shoulders in an almost hori- zontal direction. Thus situated, they made 281 turns with this machine in two hours, which gave for their relative velocity c dc 2' 4.5 feet per second. We have also the absolute force, or P, from these seven men by the above table = 730lbs. and their absolute velocity, or C = 5'30 feet. Therefore, by substituting these values in the first formula, we Results. STRENGTH OF MEN AND HORSES. 239 we find the relative force p = 205lbs. which agrees very well with what we have just found above. If instead of this first formula, the second be taken, it gives p = 153lbs. which is far too little. By this it is evident, that the first of Euler's two formulae is Enter* first to be preferred in all respects. I have also made a great num- ^J.™^ pre" ber of combinations, and I almost always found the same effect. Dividin^the 205lbs. which we have just found, by seven, the number of workmen, we get 29lbs. for the relative force, with 2'45 feet relative velocity for each man, which is rather more than the values commonly adopted in the computation of machinery. A number of other observations on different A man's machines, which I intend to relate another time, have given Jf6!^^ || |£ me the same result j that is to say, we must value the mean veloc. per human strength at 29 or 30lbs. with a velocity of l\ feet per secoud* second. To obtain the ratio of the strength of a horse to that of a man, I had the same machine moved by a horse, without alter- ing any thing ; and I found by ten different horses which I * used successively, that a horse makes 6*03 turns in two hours instead of 281 j therefore, by supposing the static motion of a horse seven times greater than that of a man, we find that the former has 5 3 feet per second of velocity. By this it is evident, that the effect of a horse is fourteen Horses exceed times greater than that of a man, or, which amounts to the ™e? 1* tim*s /- 1 1 . 1 r 1 in drawing, same thing, fourteen men must be used instead of one horse. Hence it appears, that it is much more advantageous to employ horses than men in moving machines, if other reasons did not require us to prefer men. I have also made a number of other interesting observations on horses and oxen, which are likewise used in moving ma- chines ; but as I am now waiting for observations of this kind, . which other persons are making according to my plan, I shall reserve them for another memoir. II. 240 METALLIC OXIDES. H. An explanatory Statement of the Notions or Principles upon, which the systematic Arrangement is founded, which was adopted as the Basis of an Essay on Chemical Nomenclature. By Professor J. Bekzelius. (Continued from p. 166.) of A FTER this general review of the changes which appear fs 'J\. to Indication madTnpon8 '-^L t0 be necessaiT in the theory of chemistry, I shall have the combina- the honour to present to the academy the results of some ex- tions of metals periments upon the combinations of various metals with oxi- vithoxigen f and with sol- gen and with sulphur, made with the intention partly of deter- phur for deter* mining their composition with greater precision, in order to composition refute certain incorrect notions respecting their nature, and their electro- partly to ascertain the electro-chemical nature of those metals, chemical na- ,, . . , . . , ture and rela- as we" as tne P^ce they ought to occupy in the system among tions. the other combustibles. Much remains yet to be done on this subject, because the field to be explored is so extensive, that each individual step appears relatively of small magnitude. My researches have been made upon the oxides of tin, tellu- rium, gold, platina, palladium, lead, zinc, and manganese j and at my request the following metallic oxides have been ana- lysed, namely, those of cerium by M. de Hisinger • those of nickel and cobalt byM.RathofFj that of bismuth by M. La- gerhjelm; and those of mercury by M. SerTtroud 5 and these chemists solicit the honour to publish their works in the Me- moirs of the Academy. Ammonium? I should also have wished to add to these experiments that of the production of an amalgam of ammonium produced an anhydrous ammoniacal salt ; and though in my experi- ments on that subject, an amalgam of kalium has produced an amalgam of ammonium in the subcarbonate of ammonium, prepared with the carbonic acid gas an4 dried ammoniacal gas, I shall not venture to present the same to the Acadamy as a well-determined result, because I have not yet had an oppor- tunity of examining to what degree I may have succeeded in operating with materials perfectly deprived of water. It is, neyer- METALLIC OXIDES. 241 nevertheless, clear, that the success of an experiment of this nature would be decisive as to the nature of ammonium. /. Concerning the Oxides of Antlmonium. Notwithstanding the labours of chemists have, perhaps, been On the mun- more frequently employed upon this metal than upon any uer> &c«.°t other, we have hitherto possessed but few data respecting the jdes. number and the nature of its oxides j and the information given in elementary works is often contradictory the one to the other. Thechemists who have operated the most successfully upon these oxides are, MM. Proust, Thenard, and Bucholz. Thenard, guided by the principle of unlimited combinations advanced by the illustrious Berthollet, found that antimony produced six different oxides, that is to say, one black, one chestnut brown, one greyish white and fusible, one white and not fusible, one orange, and one yellow, in which the quantity ' of oxigen differed no more than one or two per cent. Proust, on the contrary, found no more than two oxides, of which he has determined the composition with considerable accuracy j and Bucholz, who repeated the experiments of Thenard with the intention of examining them, could find only two degrees of oxicjation precisely the same which Proust had described. I The auth have found as many as four, which it is incontestibie that has found four. Thenard saw, though he did not well distinguish them from the mechanical mixtures of different degrees of oxidation, which are very frequently obtained j and though he has given no other distinctive character ihan the colour, which is so often fallacious. I must observe, that the antimony employed in all my expe- Antimony was periments was purified in the following manner : I reduced it purified by fu- to powder, and mixed it with the white oxide of antimony, ^^! lls which I ihen exposed to fire till the mixture was fused. If the fused oxide, which flowed above the metallic bottom, was found to be coloured after cooling, I repeated the same ope- ration. 1. Suboxidum stihicum is formed when the metal is exposed ± Suboxidum for a long time to the action of an humid and warm atmos- stibicnm 1; phere. It forms an extremely thin coat of a blackish grey atmosphere • colour, which prevents all farther action of the atmosphere biackish grey, upon the parts so covered. In order to obtain this suboxide in larger 242 METALLIC OXIDES. larger quantities, a piece of antimony, fused in a tube of glass, to give it a convenient form, was employed as the positive con- Also by volta- doctor in the decomposition of pure water by a voltaic pile of fifty pair. The antunony produced oxigen gns in extremely small bubbles, but, at the same time, it became covered with a grey pellicle which became almost black when the metal was - dried in the air. That part of the antimony which was covered by the cork had preserved its metallic brilliancy, and the diffe- rence between the suboxided surface and clear metal, -was very marked. But as even in this experiment the suboxide did not -appear visibly to increase as soon as the pellicle was formed, 1 employed antimony reduced to powder as the positive con- ductor, and touched at the bottom by the point of the platina Another vol- wire. This point produced oxigen gas, which, from time to onthe antim. ^ime> rose through the powder, and this last began to be covered powder. with a lighter and bluish powder. After some days this pow- der had increased so much as to be capable of. being separated from the metal by means of levigation. This becomes nearly black by drying, and, when rubbed with a polished bloodstone, Dccompos. did not give the smallest trace of metallic brilliancy. When ide bv an acid" lnrown mt0 muriatic acid, this fluid emitted a slight smell of hydrogen, and a few instants afterwards, metallic particles were seen swimming in the acid, and were more easily precipitated by soda than the powder before the action of the acid. The suboxide of antimony, therefore, possesses a property common to most of the suboxides, of being decomposed by the action of acids, by concentrating the oxigen upon part of the me- tal to produce a base combinable with the acid, and reducing the other part to the metallic state. Composition I have not been able to produce this suboxide in a sufficient ■J*, dcteomij- qUaritity to analyse it 3 but I shall hereafter shew how it is pos- sible to find its composition by calculation with some degree of probability .- 2. Oxidum 2- Oxidum stibiosum. The characters of this are very well stibiosimi. known from the experiments of Proust and Thenard. It has a fusible &c. &rfy wmte colour, is slightly soluble in water, is easily fused by a cherry red heat into a yellowish fluid. The mass, when cold, is crystallized in the manner of asbestos, but the groups of crystals cross in every direction, and it is not difficult to break their continuity. a. In METALLIC OXIDES. 243 a. In order to determine the quantities in the composition Formed with of this oxide, I digested ten grammes of antimony with nitric £ ,"ded°by ni-*" acid until they were completely corroded. I then mixed the trie acid, liquid with much water, and washed the precipitate with water uiml that fluid came off without being capable of red- dening turnsole. The oxide thus obtained weighed, when dry, 12065 grammes j and, in order to drive off all water, I exposed it in a glass capsule to an heat not as high as ignition, but it took fire on a sudden, and continued to bum like fungus, TnV.es fire by (or tinder) at the same time subliming inn thick white smoke, l^'J^' *** of which part was condensed on the sides of the glass. The white, powder, by this means, became as white as snow,, and weighed J 2*3 grammes. b. As this analytical method did not appear very good, I Another me- mixed in a small glass retort ten grammes of murias hydrargy- |„f -^ ^ a^J ricus (corrosive sublimate) in \ .-.>•■ 'der, with twenty grammes of corros. subli- powdered antimony. The atm spttertc air of the retort hav- mate mh,th'°- ing been expelled by hydrogen gas, and a small receiver rilled with hydrogen gas being also applied, I gently heated the mix- ture until the murias stibio.sus (butter of antimony) came over, and lastly 1 heated the body of the retort red hot, to distil over the mercury amalgamated with that part of the antimony which had been added in excess. The quantity of 16,98 grammes and from the r , . . ^, " , quantity of of antimony remained in the retort. Consequently ten t\,e jatt*er de- grammes of murias hydrargyricus had been decomposed by composed by 302 grammes of antimony. But 100 parts of this salt contain ^^tv 0f 5"75 of oxigen combinable with other metals. ICO parts ofamim,tae antimony had, therefore, been combined with thirteen parts ^'"{^"^je of' oxigen. were deduced, I repeated this experiment several times without having Vlz* lyQ^p?rts ' l to an tiro, ana ever obtained results perfectly equal, but varying, as for example, about 19§ oxi- 3 g,35 or 19.68 parts of oxigen for 100 of antimony The Seu- causes of error in this experiment may be several V >r in- stance, it is possible that the mercury may be so adherent to the antimony as not to be separated but at a teinpeui ;> Which would also carry over a little of the latter ; and ir is also pos- sible that a small quantity of mercurial muriate may arise be- fore decomposition along with the vapors or the muriate of antimony. It is, therefore, probable, that thest experiments may have given the quantity of oxigen rather too ^reat. In 244 METALLIC OXIDES. Indirect me- In my essays on determinate proportions, I have often ascer- Utod ot dr- tained the composition of an oxide, which was difficult to ana- ducing the . r ' components Jjse with exactness, by analysing the sulphuret of the same of an oxide, metal, aad calculating the composition of the oxide from this analysis. I endeavoured to do this in the present case. Sulphuret of 3, Sulphuretum stibii. I mixed 100 parts of pulverized an- anhmony was .. . , 1 ..'.-. 1 made by heat- Oniony with 500 parts of very pure cinnabar, and I exposed in? antimony the mixture to heat in a retort. When the cinnabar appeared ' to be entirely decomposed, and the excess driven out of the bulb of the retort, I left the sulphuret of antimony in fusion for several minutes at a cherry red heat, and then took the retort from the fire. The sulphuret of antimony weighed 137'3grs. In the upper part of the retort I found a small quantity of a reddish substance sublimed. I supposed it to be cinnabar not completely expelled, and heated the sulphuret Cause of in- again in the retort till it boiled. The red substance was in- accur cy. creased, and I at last discovered that it was crocus of antimony produced by the access of air. As the sulphuret of antimony is slightly volatile in a very elevated temperature, the result of Inference that this experiment likewise is not very exact ; but it may, how- 18 6 parts oxi- ever, be inferred, that the quantity of oxigen in the oxidium antimony stibiosum cannot be less than 18*6 for one hundred parts of form this metal. 4X\Vhitcox- 4. White oxide of antimony*., (a) Two parts of pulverized ide.Crt)Antim. antimony oxided (in a phial carefully weighed) by pure nitric ac^and^Umit- ac'I(*' and {^e ox,(*ed mass strongly ignited in the phial, pro- ed. duced in different experiments 125*8, 126:13, and 127-8 parts of white oxide. (b.) Antim. b. 100 parts of pulverized antimony first dissolved in nitro- dissolved in muriatic acid, and then precipitated and well washed with nitro-mur. ' «>.»'#. . , . , r acid, and pre- water, produced a quantity or oxide of antimony, which, after cipitated by strong ignition, weighed 12656 parts. The acid liquor, after nited. dilution, contained no more oxide, and did not become turbid Deduction, by saturation with an alkali. The experiments appear, there- 100 antim. and fore^ f0 pr0ve, that this oxide does not contain less than 258 gen which is nor more than 27*8 of oxigen to 100 parts of metal. We see, neirUf if times therefore, that this oxide must contain ]£ times as much oxi- the oxigen in the §fcmi ox- ide. * I shal! hereafter explain why I do not here use the words oxidum xtihicum. — B. gen METALLIC OXIDES. 945 gen as the preceding degree, though the exact number was not ascertained. In order to obtain a more determinate result by another pro- Exp. The ox- cess, I endeavoured to reduce the white oxide at the first degree lfca°ec ^s " of oxidation by means of metallic antimony. I, therefore, mixed heated with the metal in extremely fine powder, with less of the oxide Jjj^ w^com- than would have been required to oxide the metal. I intro- bination was duced the mixture into a small phial, of which I drew out fus,t>le> &c- the neck into the form of a capillary tube. The body was bedded in sand in a small crucible, and exposed to a sufficiently strong fire to make it red-hot j and, at the moment when the matter entered into fusion, I hermetically closed the end of the capillary neck, by melting the extremity, and I left the mixture in that heat for half an hour. Three grammes of the white oxide of antimony had oxided 0*323 grs. of metallic an- timony, and afforded a fusible oxide. I reduced this again to powder, and mixed it with powdered antimony, after which I fused it in a similar phial -y but in its present state it was ca- pable of dissolving only a small quantity of antimony, which would have been correspondent with 003 grs. of antimony upon the whole quantity of oxide. The fused oxide wrhich I had obtained by this operation, was of a pearl colour, its frac- ture crystalline, granulated, and very compact j it was ex- tremely coherent, and difficult to break, and all its external properties proved that it was not a pure stibious oxide. I re- peated this experiment several times, and always found that the white oxide, fused with metallic antimony, dissolved one- third morethan it before contained j that is to say, that 100 l CO parts ox- parts of the oxide can oxide an addition of 26 parts of the l^mor^of^ metal; and if we attend to this result, which is determined metal, with the utmost possible accuracy, we shall find that the fusible oxide produced, of which the external characters are so difFe- ent from those of the oxidum stibiosum, cannot be the same as this last ; but that it must be a combination of the oxidum forming a stibiosum with the white oxide in such proportion that the oxi- compound of gen of the former is double that of the latter. Such combina- 0xidesS of Cr# g.'s rea munication to show, that the observations of this ingenious *°ns for quot- foreigner are, on all his main positions, unfounded: and, al- tScs.81""10"" though the matter under investigation is, in general, so nearly elementary that any man of moderate scientific attainments might safely rest the truth of his assertions upon his own cha- racter and their intrinsic evidence ; yet, lest it should be ap- prehended that, on this occasion, my judgment may be warped either by strong national feeling, or by private attachment, I shall fortify my positions, as I go along, by such authorities as neither Don Rodriguez, nor any other person, will be inclined to question. Before I proceed to the points which Don Rodriguez selects as the basis of his animadversions, it may not be thought im- proper if I briefly advert to what appears hi New Series, Did not Professor Playfair solve the general problem in all Nos'i^V?t\ lts useful varieties in the Edinburgh Transactions, before the or vol. VII) J ° ' publication ot Deiambre's investigations I Did not General Roy, and the subsequent English measurers, publish ingenious formulae in the Philosophical Transactions, although Don Ro- EnglishTrig. driguez insinuates, that their methods are kept back? And, Survey com- wjtn reSpSCt to riCtuai admeasurements, might not the Don the French have learnt from the Philosophical Transactions (see vols. 75, revol. jjf 80^ £c.) ti)at government surveys were commenced in Scotland so long back as J 745, by Lieutenant-General Watson 5 that in 1775 the work was continued 3 that in 1783 an autho- rized committee or deputation of the mathematical philosophers of England and France met at Dover to concert the best means of carrying a series of triangles from Greenwich to Paris ; that the work was soon after pursued by the appointed persons in both countries j and that, from that period it has almost regu- larly proceeded in England, whatever interruptions it may have experienced in France ? How, then, can a writer insert in the Philosophical Transactions, where evidence to the con- trary abounds, a paper from which all who are unacquainted with the history of this important class of operations, would conclude dr. Gregory's strictures on don Rodriguez. 249 conclude, that they originated in the determination of the French to u establish a new system of weights and measures." To the same end, apparently, tends the Don's assertion, that " the Swedish Academy of Sciences, encouraged by the success of the operations conducted in France, sent also three of its members into Lapland to verify their former measurement." For the natural tendency of this statement is to produce the Hisron of the belief, that the recent operations of the Swedish philosophers New LaP'an<* were in humble imitation of the French, and that they were undertaken for the purpose of verifying, or of correcting, their own former admeasurement ; in both which respects the co- louring given is widely different from the truth. The Lapland measure in 1736 was not conducted by Swedish, but by French academicians ; and the correction of it was proposed long be- fore the French revolution. The following are the true cir- cumstances of the case, as I received them from a learned Swede. Melanderhielm, the venerable president of the Stock- holm academy, had almost from his youth doubted the accuracy of the operations of 1736, and sought anxiously for an oppor- tunity of repeating them ; but waited many years before he could avail himself of a favourable conjunctuie of circum- stance, although latterly he had found in M. Svanbcrg, a young man of great talent and activity, to conduct the operative part, After hearing of the new measure of a degree by MM. Ddambre and Mechain, he wrote to some of the French mathe- maticians on the subject, but with no intention of soliciting them to visit Lapland. Soon after this, Buonaparte, at the an;! of Bno- siiggestion of the then national institute, wrote a letter per- Jla,^r^'s, ^'^ sonaliy to the late king of Sweden, requesting permission for of Sweden, some members of that body to proceed to Lapland, in order to determine an arc of the meridian. That high-spirited young monarch replied, that he would consult his own Academy of Sciences at Stockholm, whether such an operation was desirable for the interests of science j and if they were of that opinion, he had no doubt he could find Swedish mathematicians com- petent to the undertaking. Hence MM. Svanberg, Ofverlom, Holmquisi, and Palander, were appointed to examine and re- peat the measure of the French academicians ; and this is what Don Rodriguez terms the expedition of three of the Sivedish academicians " to Lapland to verify their former measurement." ■ Vol. XXXIV.— No. 159. S With 350 Col. M. com- With the same spirit, it is natural to suspect, Don Rodriguez Don^R* by sPca^s of Colonel Mudge as " a skilful observer," and merely merely as a such j adding, that " one cannot but admire the beauty and skilful observ- perfection of the instruments employed" by him : while, when he characterises the labours of the French measurers, he assures us they " merit the highest degree of confidence," and, " by the sanction of such an union of talents, give such a de- gree of credit and authenticity to their conclusions, as could scarcely be acquired by other means." I shall not animadvert upon this invidious contrast j but simply remark here, that the Don adopts a strange method of verifying his positions. He admits, that Colonel Mudge is a skilful observer, who knows very well how to employ his instruments j and, that there may remain no doubt on that head, publishes a long paper to prove, or at least to show it probable, that he has made a mistake of 4| seconds in the determination of a zenith-distance. This animadverter has, as he assures us, gone through all the Colonel's computations by different processes, and found them correct, or only evincing very trifling discrepancies, such as may naturally arise from the diversity of methods ; yet he cannot find in his heart to drop a single word of commendation on him as a computer or as an investigator. The preceding remarks will suffice, 1 apprehend, to render manifest the probable object of Don Rodriguez's paper. I shall now proceed to enquire how far the reasons assigned by this gentlemen bear him out in his attempt to throw suspicion upon the operations of Colonel Mudge, in measuring an arc of the meridian. The Don's paper, it is true, is rather desultory and unconnected ; but, I trust I shall neither misrepresent him, nor do injustice to his arguments, by endeavouring to reduce them to the following order: Don. R. s first * • Colonel Mudge's observations must be wrong somewhere, reason for because his results do not correspond with those of the French thTacairacy nieasurers. This is not positively affirmed, but every where of the Eng- strongly implied : for Don R. assumes his value of the radius tlons^efilted of tne earth's equator from the French measurements and com- putations j and he takes it for granted, that the fraction exhi- biting the ratio of the difference of the earth's axes to the major axis, technically termed the cotripression, lies somewhere between those limits, (. JL- and _i_ ^ which a superficial ob- V 3 3 0 <* ) 0'/ server DR. GREGORY S STRICTURES ON DON RODRIGUEZ. 25 1 server would adopt as most suitable to the French operations. Such assumptions, by the way, are neither consistent with fair criticism nor with sound logic : for the grand object in measuring arcs of meridians is to determine the ratio of the earth's axes $ and when, in the course of any such admeasurements, avowedly remarkable anomalies arise, it is a mere petitio principii to con- Tjie prenc|j elude that there must be some error in the astronomical observa- operations tions, because irregularities as great or greater than those l"^^rregtt which the operations indicated, result from computations rest- tatties. ing upon a gratuitously assumed ratio. But some of the French operations at home, compared with those at Peru, give about -j-i-^. for the compression*. Be it so. That is no reason why any such ratio should be adopted, as the test by which to try the accuracy of English observations. Don Rodriguez himself, when applying the same test to the French meridian, thereby detects irregularities, and great ones too j yet does not whisper the gentlest hint that they were occasioned by inaccurate observations. Why not ? Because M. Mechain €< handled instruments with great delicacy, and was possessed of peculiar talents for this species of observation." 80 that a gratuitous assumption should suffice to render English observa- tions doubtful, while it leaves the accuracy of French ones unimpeached. To me it appears that a candid critic would, in analogous circumstances, make analogous inferences ; and not sift one class of results to the bottom, while he satisfies himself with merely glancing at the surface of the other class. Had he examined the French measures a little more minutely, he would, instead of adopting them as his standard, have found that they exhibit far too great irregularities to be entitled to that honour. Taking the results of the operations ofDelambre and Mechain, as subdivided naturally by the assumed stations at Dunkirk, the Pantheon at Paris, Evaux, C^-ji^one, and Mbntjouy, and applying to them the principle developed by £egendre, in which, " the sum of the squares, of the erFoY9 is Some anoma* made a minimum," the requisite compression is ~\- ; and even fvJn"h }C then the deviations from what the theory would require are, at measures. Dunkirk— 2"*23, that is, nearly 2$ decimal seconds j at the- Pantheon, + 5"63 $ at Evaux, —4 '79 j and at Carcassone, * Biot. Astronomic Physique, lorn. i.'p. 15°. S 2 + 1"'34. $5% dr. Gregory's strictures on don Rodriguez. V>ou K.'s 2d reason refut- ed. Former measures do not agree in their results,; Don K. iifirms. -h r'*34. Here the compression which agrees best with the observations is more than double what it ought to be. If a medium compression had been chosen, the errois at the several station would have deviated still farther from the probable errors of observation. Don Rodriguez will find this confirmed by Puissant, Geodesie, pa. J 3/. 141, and by Laplace, Exposition du Sysleme du Monde, Liv. i.eh. 12. After he has duly reflect- ed upon the deductions of those philosophers, he will, perhaps, be convinced, that he has been rather precipitate in taking the French operations as a standard. But, secondly, this writer infers that there must be some error in Colonel Mudge's observations, because they tend to shew that the terrestrial spheroid is very irregular. All the measure- ments " which have been hitherto made in the northern hemisphere, are (he tells us) extremely satisfactory by their agreement, and give us great reason to presume, that the general level of the earth's surface is elliptical and very regularly so." " There woulcinot have remained the smallest doubt respecting the earth being flattened at the poles," but for the " measure- ment performed in England." But " this measure alone would lead to the supposition, that the earth, instead of being flattened at the poles, is, in fact, more elevated at that part (the author means those parts) than at the equator, or at least, that its surface is not that of a regular solid." The degrees, in fact, increase as the latitudes diminish, which, says Don Rodriguez, " excites a suspicion of some incorrectness in the observations them- selves ;" whereas, the only fair inference is, that an insular situation is very ill fitted to promote the determination of the figure of the earth. Let us see, however, how " satisfactory" former measures have been " by their agreement " and how completely they prove that the earth's surface is " very regularly" elliptical. Lacaille's degree in lat. ^5° N. compared with Bouguer's at the equator, gives for the compression -^-L-. The degree in Maryland, with Bouguer's equatorial, gives -3--^. The Spanish degree at the equator, with tne French degree lat. 45°, gives -j-J-y. Boscovieh's Italian degree, lat. 43°, compared with Bouguer's at the equator, gives ^. J T Bishop Horstey, by a geometrical mean of iwelve different ellipticities, obtains ^fa** Boscovich, taking a mean from all the measures of degrees, so as dr. Gregory's strictures on don Rodriguez. 253 as to make the positive and negative errors equal, obtains T^T. Summary of Lalande, by comparing Father Leisganig's degrees in Germany staten,cnts? with eight others in different latitudes, gets _^-T. And the recent measures in Fiance give, as we have seen, T^-g.. Such is a summary of the evidence from which it is to be concluded that the earth is " elliptical," even " very regularly so." General Roy, who had got a habit, not very uncommon among scientific Englishmen, of deducing reasonable conclusions from anomalous aml (;enerai appearances, and not twisting them to suit a fanciful hypothesis ; Roy's deduc- assumed seven different spheroids of varying ratios between ^em. r° -j-4-jj. and ^i^, and, on finding that none of them corresponded so uniformly as might be wished, with the operations in different latitudes, made these inferences : f Hence it is obvious, that the arcs of an ellipsoid, however great or small the degree of its oblateness may be, will not any way correspond with the measured portions of the surface of the earth." " Hence it is that philosophers are not yet agreed in opinion with regard to the figure of the earth j some contending, that it has no regular figure, that is, not such as would be generated by the revolution of a curve around its axis." And again, after specifying some other facts, " from all which we may conclude, that the earth is 720/ an ellipsoid." Nor is this opinion peculiar to General Roy, it is common, I believe, to all who have contemplated the subject, except Don Rodriguez. Thus, Puissant, at p. 187, °f his Geodesie, says _ . M . ■ .Puissant s " La comparaison des divers degres measures & l'equateur, en dednctioB* France,en Pensylvanie,etc.donnelieu a decider que les meridiens §ont differens entreux et n'ont pas la forme elliptique." And at p. 222. M D'on Ton doit conclure que la terre ria point la forme reguliere que Ton serait tente* de lue attribuer." To the same purpose writes Laplace, at p. 56 of his ft Exposition :" f Les Laplace's degies du nord et de France donnent ^\^ pour l'eHipticite de la terre, que les degres de France e*t de l'equateur, donnent egale a -3±^ 5 il paroit done que la terre est sensiblement » - diffcrente d'un ellipsoide. II y a raerae lieu de croire qu'elle ti 'est pas un solide de revolution, et que ses deux hemispheres ne sont pas semblablesde chaqUecote de l'equateur. It is curious, however, to observe that, notwithstanding this extreme want of uniformity, in the results furnished by terres- trial S34 DR. GREGORY S STRICTURES ON DON RODRIGUEZ. lium, and agronomical theory. trial admeasurements, those which are deduced from astrono- mical theory, and the oscillations of pendulums, correspond The only infe- very nearly. Thus, Laplace's deduction of the compression. renccs which from the lengths of pendulums in different latitudes, is ----1 . agree are those ° r 333 7h from pendu- (See Puissant, Topographs, &c. p. 66.) Clairault's well known modification of Newton's theorem, derived from the diminu- tion of gravity, gives -5--^. The phenomena of the precession of the equinoxes and the nutation of the earth's axes, give ^lf for the maximum limit. A lunar inequality in longitude depending upon the earth's ellipticity, and expressed by — 20/A 987 sin. ft of the moon in longitude, requires the com- pression to be between ^4 and ^j.^.^.^., but nearest the latter limit. And a lunar inequality in latitude, depending also on the compression, and expressed by — 24;/ 6gi4 sin. J) , requires the compression to be between -j1^ and -J^^.1-> still leaning to the latter limit. So that the ratio of the earth*s axes, as deducible from these independent theoretical considerations, lies within much narrower limits than we can get in any other way. But this does not affect the truth of the preceding remarks. It serves principally to shew, that whatever may have been the derangements of the terrestrial spheroid since its original formation, they are not such as have differently affected the several phenomena occasioned by its aggregate attraction : while a very slight consideration of the effects of the deluge, of earthquakes, of volcanic operations,.of extensive dislocations of strata, &c. may serve to convince us, that, however regular the earth might once have been in its general shape, there is now no reason to expect that " very regular" surface from which Don Rodriguez persuades himself there ought to be no essential deviation. A 5d reason of 3. Don Rodriguez is farther confirmed in his opinion, that the Don's re- ihere must be an error in the observations, especially at Arbury Hill, of *f nearly 5 seconds," because he thinks no such anomaly as that can fairly be ascribed to the effect of local attractions. He does not deny " that irregularities of the earth and local attractions may occasion considerable discrepancies ;" yet be does not believe they can ever produce a deviation of the magnitude just specified. Here again he is at war with the decisions, I believe, of all preceding philosophers who have directed Remarks 00 this fact. futed. dr. Gregory's strictures on don Rodriguez. £5.5 directed their attention to this subject. There are, obviously, Three causes three causes which may jointly or separately occasion a deflec- 0ftheplumb- tion of the plumb-line from the true perpendicular to the line, earth's surface ; namely, an insular situation, the attraction of mountains, and strata of unequal density beneath the surface : and either of these may be productive of considerable effects. To arrive in the easiest manner at an estimate of the effect upon a plumb-line arising from observations made in an insular situation, let Don Rodriguez imagine the simple case of a triangular island so posited on the surface of an aqueous spheroid, that a meridian shall run along from its vertex, directed northward to the middle of its base : he will perceive that, in such a case, as an observer proceeded from the south towards the north, there would be a constant variation in the deflection of the plumb-line ; in such manner, that there would be only one point on the meridian, where the attractions occasioned by the island itself should be so counterpoised and adjusted, that the true and observed vertical lines should correspond. Pursu- ing this hypothesis, with the requisite modifications for a neighbouring continent on the south, and an immense ocean north, he will find that the singular order exhibited by the English estimates of degrees, though an unexpected, is by no means an unnatural, consequence of our insular situation. Dr. Dr- Hutton on Hutton has treated this very point with his usual perspicuity, from gn«nff^ in a valuable note at page 198, vol. ii. New Abridgment of the situations. Philosophical Transactions , published in 1803. That note is too long to be copied into this place j I shall, therefore, merely transcribe the Doctor's concluding inference : " Hence also it follows, that insular situations must be worst of any j having the plumb-line deviating to the north at the south end of the line, to the south at the north end, to the east at the west side, and to the west at the east side j thus producing errors in all observed latitudes and longitudes." Laplace, most probably alludes to this kind of effect, at p. 5Q, Laplace ditto. "Exposition," where he speaks of the much more extensive attractions than those of mountains, of which the effect is sensible in 1 taly, England, &c. That the deflections of the plumb-line, and the consequent estimate of the lengths of degrees, must be greatly affected by hills and valleys, is also very manifest. Professor Playfair, after 256 DR. GREGORY S STRICTURES ON DON RODRIGUEZ. Plavfii iron Hi e attraction of hills, &c. Maskelyne. Cavendish. Puissant on local attrac- tions. Playfair on after describing the irregularities thus occasioned in the degree at Turin, adds, " there are, no doubt, situations in which the measurement of a small arch might, from a similar cause, give the radius of curvature of the meridian, ivjhrite, or even nega- tive." See Edinburgh Transactions, vol. v. p. 5. And Dr. Maskelyne, after treating of Mason and Dixon's degree in North America, says, " Mr. Henry Cavendish having inves- tigated several rules for finding the attraction of the inequa- lities of the earth, has, upon probable suppositious cf the dis- tance and height of the Allegary mountains, from the degree measured, and the depth and declivity of the Atlantic ocean, computed what alteration might be so produced in the length of the degree ; and finds that it may have been diminished by 60 or 100 toises by these causes. He has also found, by similar calculations, that the degrees measured in Italy, and at the Cape of Good Hope, may be very sensibly affected by the attraction of hills, and defect of the attraction in the Medi- terranean Sea and Indian Ocean." Phil. Trans, vol. Iviii. or New Abridgment, vol. xii. p. 578. With respect to the third cause of irregularity, Puissant, Geodesie, p. 137, remarks, that " anomalies in the latitudes, are, doubtless, produced by local attractions which change the direction of the apparent vertical." And Professor Playfair, in the excellent memoir I have just quoted, (a memoir, it should he recollected, which was written five years before the remarkable anomalies in the English measures were known) affirms., that " from suppositions no way improbable, con- cerning the density and extent of masses of varying strata beneath the surface, he has found, that the errors thus produced, may easily amount to ten or twelve seconds.'" " This cause of error, (as he justly remarks) is formidable, not only because tt may go to a great extent, but because there is not any visible mark by which its existence may always be distinguished." Here, then,, are three sources of deflection from the true plumb-line, neither of which is correctly appreciable in all circumstances, yet of which each may be not only percep- tible, but important j and the concurrent effect of all may, doubtless, be vory considerable. Yet, Don Rodriguez is un- willing to attribute a deviation of 4. or 5 seconds, to any, or all, of these causes. 4. This dr. gkkgory's strictures on don Rodriguez. 257 4. This writer infers, that mistakes mu6t have occurred in Don R.'s 4th the (jbjerrafipns, because the sum of other " errors will he™™^^™' found in the estimate of the entire arch, and will increase in place, proportion to the extent of the are measured j but in the English measurement, we find exactly the reverse of this." Here he assumes the principle proposed by Boscovich, but condemned by Laplace, for a reason thus briefly assigned by Puissant : — ' J, a solution donnee d'abord par Boscovich est vicituse en ce quelle est fondee sur une hypothese inadmissible, savoir, que leserreurs dans le mesure des arcs du meridien sont proportioned a leurs longueurs." 5. He concludes that there must be "an error of some Don R.'s 5ih seconds in the observations of the fixed stars," because " the r(H.soin ot' n<> weight* results of the observations made on different stars, differ no Loss than 4 second* from each other." Now, what are the facts on which this inference rests ? Simply these : that the only two. stars which indicate any such difference in the whole series of observations, are p Draconis and f Ursae ; that they because the give a difference of 4"'l(j, not in the amplitude of the arc stars» where between Dunnose and Arbury Hill, but of that between Dun- regularity do* nose and Clifton ; and that, whether these two stars be rejected, ,lot apply to or retained with the other fifteen employed in finding that cHfto£ amplitude, they will not occasion a difference of a quarter of a second in the result. How, then, can a fair investigation, bring this as a reason for an alleged inaccuracy, when it obvi- ously cannot apply to the ease? And what must be thought of his impartiality, if it shall appear, that even in this respect, the observations of the French and of Major Lambton, which he so manifestly prefers to the English observations, are far more* open. to censure ? Allow me, therefore, just to make the com- parison . • Of the English observations, none are suppressed, (the ob- servers going upon the principle explained by Simpson, in his "Tracts," which clearly establishes the propriety, if not the. Much greater necessity, of taking the mean of a number of observations) jnr«8ulFr,tl Aquilae, of which two differ by 6"' 77. At p. 358, we have 18 observations upon Atair, of which two differ by 5'1' 38. There are also some other palpable differences in Major Lambton's results, as de- duced from different stars. The greatest is between Atair and Markab, being 5" 48. Atair, from the number and agreement of its observations among themselves, should be correct in zenith dr. Gregory's strictures on don Rodriguez. <259 zenith distance, yet it gives the latitude of the station, Doda- goontabj less by 3"' 4 than the mean of the nine stars, employed by Major Lambton, exhibits it, and the latitude found from a mean of the four northern stars, is 2' '04 greater ihan the latitude found from a mean of the five southern stars. Dis- crepancies of more than 4" may likewise be frequently found in the observations recorded in vol. viii. of the "Researches." Most of them are,- probably, in great measure, attributable to the imperfections in Major Lambton's sector, which is only of 5 feet radius (while the English is of 8 feet) ; and is pro- vided with but few comparatively of the requisite means of adjustment : but whether they are to be ascribed to the observer or his instruments, they prove that Don Rodriguez has been rather precipitate in saying, " the same Major Lambton, who has . succeeded so well in Asia, gnd is rn possession of such per* feet instruments for the purpose, would be singularly qualified for a similar undertaking in Africa." In matters which admit of examination and proof, it is not the custom with English- men to bow at once to the authority of a mere ipse dixit. Was Don Rodriguez really ignorant that, with respect to accu- racy of observation, the English proceedings are thus greatly superior to those of the French and of Major Lambton } If so, how greatly is he to be pitied for writing so much on a subject he had previously so little considered. If he was aware of this superiority, how much more is he to be pitied, for giving so unfair and unnatural a representation of the business before him. From one or other of the reasons I have thus examined, Don Rodriguez says, " it is almost beyond a doubt that it is to errors in the observations of Jatitude," the singularity in CoJ. Mudge's results must be ascribed. There must be an error of some seconds in the observations, " especially at Arbury Hill." And he asks, " How is this to be discovered ?" How ? Why, by simply repeating the observations at Arbury Hill. The ^r^y ^j not position of the station is so clearly described in the Philosophical the Don recur Transactions, that any person may find it within 20 feet -, and t°st o/repeat- the farmer who owns the field, can show the identical spot. Don ing the obser- Rodriguez, or some one of his friends, has, doubtless, handy ^burl^ circular instruments of the French construction, by which the zenith distances could readily have been taken, and then the correctness £(H) dr. Gregory's strictures on don Rodriguez, correct nesa cr incorrectness of the English observers might have been proved in a way from which there could be no appeal. Though, to be sure, if that plan had been adopted, and the English results had, in consequence, been verified, Don Rodriguez's paper could never have appeared. There is, however, a method of determining the point, oven without taking this trouble. Having then shown, I trust satisfactorily, that Don Rodriguez's reasons for imputing an error of 4 or 5 seconds to the English observations, are nuga- tory^: I shall now proceed, with all possible conciseness, to show that there cannot he an error of one second either in the obser- vations at Arbury Hill, or at Dunnose; and those at Clifton are, by the Don's own concessions, out of the question. The mode of First, the manner of fixing the zenith sector could not lead *^ith^tbtorZe" t0 error> for> " to Procure for the external stand (says Col. precludes er- Mudge, Phil. Trans. 1803) and thence for the whole apparatus, ,or' a firm foundation, I caused four long stakes to be driven into the ground, one for each foot of the stand, to which its feet were firmly screwed down. The surfaces of the stakes were cut off smooth, and brought into the same horizontal plane, by which means the interior frame and sector were placed much within the limits of their several adjustments." The whole was enclosed in a suitable observatory. Don Rodriguez may perhaps think the French method of fixing their instruments, on some occasions, preferable to this. French obner-The reader shall judge. Their instruments, both for taking vations atCha- horizontai an(j vertical angles, were sometimes placed on tot- during a high tering stages, so as to give anomalies in the angles from 5 '* to wind, on a q// furnishing, as Delambre terms them, " le tourment des stage so tot'er- 3 %*,, „ tm i-. i- • ing, that even observateurs. Thus, at p. 40, Discours Preliminaire, we are a little breeze xo\d that at Chatillon, there was a high wooden stage erected much disturb- „ , . . . , , , , „ , ed the observ- *or an observatory, m which the carpenter had so badly done crK* his work, that " le meindre vent agitoit toute la machine, de maniere n©n settlement a rendre les observations moins sures, mais ainquieter les- observateurs." And on turning to p. 174, tome i. it will be seen that the observers had not to contend with a gentle gale j for they there tell us of the " Grand vent qui ngiioit le signal et 1'instiument." The whole was blown down shoi tly after. Will Don Rodriguez place reliance on observations made from such a platform in such a wind ; and, notwithstanding, i>r. Gregory's strictures ox don rodrigukz. 261 notwithstanding, doubt the observations made with a stable instrument by the English ? And let him not forget, that what- ever error was thus occasioned in the distanoe between Bois- commun and Chatillon, is more than doubledln all the remain- ing triangles of the series, by reason of the bad shape of the triangle, Chatillon, Boiscommun, Chateauneuf. If no error in the English observations can be fairly imputed NTo error ran to the manner of fixing the zenith sector, neither can any be 2JJX^Jta ascribed to the " construction" of the instrument itself. This the cmwtrttc- was most positively declared by two very excellent judges, the t,on^. the late astronomer royal, and the Hon. Henry Cavendish, on their close examination of the instrument. It will also be inferred, without hesitation, by all competent judges, on reading the description of it in the Phil. Trans, for 1603. To those who have seen neither the instrument nor the description, it may suffice, if I remark, that the equality of the divisions on the or to suUse- arch, is evinced from this consideration, that on running the qnentderange- micrometer screw from division to division, over the whole arch, there was no where an indication of an error amounting to half a second ; and that the instrument still continues free from important " derangement," is tolerably well proved by this, that the line of collimatton has been constant during all the observations and all the journeyings of the sector, and that it still continues the same. la the next place, it may be remarked, that no error in observation can be imputed to a deviation from " vertical posi- or to a devia- tion" in the sector. Important inaccuracy, in this respect, t!°" from. Ter" is precluded by the great length of the axis, by which the instrument is rectified ; and by the ready and certain means of placing the plumb-line directly over the illuminated dot which marks the middle of the axis, or true centre of the divided arch. For want of these admirable modes of correc- tion, all previous instruments are necessarily imperfect. It appears from Phil. Trans, for 1803, pp. 405, 406, t»at when the instrument is adjusted in one position by means, of the plumb-line and dot, it is turned to a position at right angles to the former, and the adjustment confirmed ; and this being the case in these two situations, the instrument must neces- sarily be vertical in all others. Various reasons may be assigned to show that the sector could not, 262 dr. Gregory's strictures on don Rodriguez. i or to a devia- not, at any of the stations, be out of the plane of the meridian, plane "of1 the* sna'l select only two or three. As 1st, if the sector were meridian; inclined to that plane, just so much would the path of any star, in its apparent motion, be inclined to the horizontal wire of the telescope j instead of which, both Colonel Mudge and Cap- tain Colby assure me, that when a star came into contact with the wire, the light of the star would appear on both sides of the wire for about three-fourths of a minute of time, the light on each side being equal at the central wire : which of itself is a positive proof. But, 2dly. had the sector been out of the plane of the meridian, the times of the transits of the extreme stars em- ployed, as compared with two excellent time-keepers, must have shewn it. Farther, the errors arising from a wrong plane of the meridian, being comparatively very great in the extreme stars, and small in those near the zenith, it would follow that the error in Capella, which is almost at the extremity of the arch, would be great, compared with those in /3. Draconis, k Cygni, &c. which were within a small distance of the ze- nith. But the amplitude of the arch, between Dunnose and Arbury Hill, as derived from Capella, is 1° 36' 20* ''02, while those derived from the other two stars, are J °36" 19-"42, and 1° 36' 1Q*"Q4: a coincidence which proves that the in- strument could not possibly have any perceptible deviation from the plane of the meridian at either station. Other reasons for coming lo the same conclusion will appear, on attending to the precautions in adjusting by double azimuths, &c. as described in the Phil. Transactions. The correct position of the sector in all respects is further or to its use proved from this : that the observations, however distant in m anyway, point of time, when the proper corrections for aberration, nu- tation, &c. are applied to them, reduce always very nearly .to the same mean place. Hence, it must be obvious, that no error could arise, as Don Rodriguez suspects, from the instrument, whether in " vertical position, construction, or some accidental derangement." I shall now advance still farther, and prove that there is no rp. error in fact. For if there were any error in the zenith dis- not be an error tances at Arbury Hill, it would at once be detected on com- even of half a parjson -with the observations at Blenheim. Now, the distance Arbury or between the parallels of latitude of Blenheim and Arbury, 139,822 da. Gregory's srictures on don Rodriguez. 263 139,822 feet, furnished by the survey, gives for the correspond- Dunnose, lin- ing celestial arch, 22' 5Q'"33, while the observations of y Dra- less ther? be . t,, , . , . , , , . . errors of the coins at Blenheim, compared with the observations upon the same, or great- same star at Arbury Hill, give 22' 5Q"6. So that there cannot fr magnitude, possibly be an error of half a second at Arbury Hill, unless vatories at the observations, for five successive years ai Bteyaheimi were all Blenheim and wrong : and Blenheim observatory, be it recollected, has been long celebrated for the excellency of its instruments ; and is select- ed even by Suanlerg for the accuracy of the observations there made. — So, again, with regard to the Dunnose station, the latitude of Portsmouth observatory, as inferred from the said station, and the data in the Trigonometrical Survey, is 50° 48' 2'"65 ; while the Requisite Tables, the edition of 178I, give it 50° 48 '3*''. So that the observations at Dunnose cannot possibly err half a second, unless there was an error made by Witchell and Bayley, in determining the latitude of Portsmouth obser- vatory, with an admirable mural quadrant, by Bird. These two deductions, then, completely exclude sensible error at punnose and Arbury Hill : and these inferences, it is evident, might as easily have been made by Don Rodriguez as by me. This gentleman may find still farther confirmation of the truth of the whole survey, if he will examine the operations by which the meridian of Dunnose is extended to Burleigh Moor, and those for carrying on a new meridian from Black . Down to Delamere Forest. These, it is true, are not to be found (for what reason I cannot say) in the Philosophical Tran- sactions. But they may be seeir in the third volume of the Trigonometrical Survey, published in 1811; by order of the Board of Ordnance ; a volume with which some of Don R.'s friends in England are doubtless acquainted. As a last corroboration of the whole portion from Dunnose Confirma- to Clifton, amounting to 2° 50' 23"3S ; let me add, that when tion of the compared with the meridional arch of 3° f l" at Peru, by furnished by means of the valuable theorem, investigated by Professor Play- Professor fair, (Edinburgh Transac. vol. v. pp. 8, 9.) for the comparison mu^ aif™ °£ of large arcs j it produces ^^.^ for the resulting compres- comparison of sion. While Svanberg (pa. 192, " Exposition') gives — _L — thef only ^ for the compression, as deducible from a comparison of his mean .of infer" . T , _ urn? the ratio measure with that at Peru. of the earth's Thus, we have confirmation upon confirmation, of the cor- axes> twm ter" * restrial mea- rectness snres. ' 261 WAtf£fi in muriatic Acta gas. lectness cf Colonel Murlge's operations, both general and par- ticular $ and of the extreme rashness with which Don Rodri- guez has affirmed, that " it is very evident .that the zenith dis- tances of* stars taken at Arbury Hili are affected by some con- siderable error ." The matter in question might, as you will 1 perceive, have been settled in narrower compass ; but the cele- brity of the institution under whose auspices the Don's animad- versions are circulated, seemed, in some measure, to call for a tolerably full reply to his paper. For the reply here presented, the public must consider me alone as responsible : and I trust that when the two papers have been compared, I shall not be thought to speak incompatibly with the courtesy due to a foreigner, or the respect dirc to a brother mathematician, when I say that Don Rodriguez has completely failed to establish the point, respecting which he ought to have felt certain before he commenced his strictures. OLINTHUS GREGORY. Royal Military Academy, Woolwich, March 5th, 1813. IV. On the Existence of comlihcd Hater in muriatic acid Gas. By J. Murray, Lecturer on Chemistry, c5"c. Edinburgh. To Mr. Nicholson. Edinburgh, March 3, 1813. SIR, Late experi- 1TN your Journal for January, an account is given of an ex- HeDa°v Sh -**- Periment performed by Sir Humphry Davy in the College Laboratory of Edinburgh, in relation to the question on the existence of combined water in muriatic acid gas. I had found that the salt formed by the combination of this gas with am- monia, affords water when it is exposed to heat ; and this water, I inferred, is derived from the acid. Sir H. Davy supposed it to be water which the salt had absorbed from tie air • and he and his brother affirmed, that when the air is excluded, none is obtained. I resumed the investigation, and found that the salt WATER IN MURIATIC ACID OAS. 265 salt absorbs no water from the air, and that it affords water Muriate of when heated, though the air has been excluded. The same ®oJ. absorb results were obtained by Drs. Bostock and Traill. It remained, wat*>r from therefore, for Sir Humphry either to shew that they were the air* not correct, or to establish, by farther evidence, his former statement. With this view the experiment, above alluded to, has been performed. About go cubic inches of muriatic acid gas were combined with the requisite quantity of ammo- niacal gas, in an exhausted retort of the capacity of 26 cubic inches, and the sale formed having been heated in the same re- tort, closed at its extremity by a stop-cock, water was obtained from it in small quantity, " a dew just perceptible lining the cold neck." On this experiment I have how to offer a few ob- servations, and I have to state the result of another since per- formed. When the experiment was made, I was informed by Df. The retort in Hope of the result, and of the manner in which it had been Sir H.Davyi r t experiment executed. I stated to him in what respect it appeared to me was too large, objectionable, independent of the unfavourable circumstances inseparable from the mode of heating the salt in a close vessel ; the large size of the retort rendering it difficult to apply the heat equally, so as to expel the water from one part without its condensing in another, allowing, too, a larger portion of any ' vapour disengaged to remain in the elastic form while the heat was kept high, and equally permitting its condensation wheri the heat diminished over an extensive surface, encrusted with a substance by which it would be absorbed, the unequal applica- tion of the heat producing a similar volatilization from one part, and condensation in another, the confinement of the And the coto* heated elastic fluid operating by its pressure in resisting the sepa- y^™^*^. ration of the water from the salt, and by its temperature cOUn- paration and teracting the local condensation of the portion evaporated, and condensation lastly, the encrustation of salt which had been allowed to remain at the curvature and upper part of the neck of the retort, where, in such an experiment, the condens tion of moisture chiefly takes place, were all unfavourable to the result. If the experiment had been one in which a considerable quantity of wattr was to be looked for, these circumstances might have been of less importance. But this not being the case, it was more necessary to attend to their influence, and every arrange- Vet. XXXIV.— No. 159. T ment 266 WATER IN MURIATIC ACID GAS. ment with regard to the experiment, ought to have been ren- dered favourable to the result, instead of being truly the re- verse. Fit conditions: The principal circumstances which I conceived required to sel, heat ^e attended *°, were, to employ a much smaller vessel, to raise equally dif- it through its whole capacity to an equal heat, to have the part liTed'TaiTat of the apparatus in which the water is to be condensed free place of con- from salt, and to avoid, as far as practicable, the operation, pressure* nor eillier of Pressure> or of a partial vacuum. It was nearly in vacuum.' this manner, that the experiment was performed by Dr. Bostock and Dr. Traill, and hence their successful result, while Sir Hum- phry, from not attending to these circumstances, was less suc- Kepetition of cessful, though performing it on a much larger scale. Dr. exp. before Hope, anxious to ascertain the matter of fact, readily agreed eminent men. , . , } ° to repeat the experiment with these variations ; Lord Webb Seymour and Mr. Ellis were present, and I haye his permission to communicate the result. Mur. of am. Ammoniacal gas, previously exposed for two days to dry irom dried potash, and muriatic acid gas which had been exposed to dry gases was ex- . r .. ■ nj ,° .... , J posed to equal muriate or lime for 24 hours, were combined in a dry ex- heat in a small hausted flask, of the capacity of 3*8 cubic inches. About QO cubic inches of the acid gas were employed, and the flask re- mained at the end filled with ammoniacal gas. The stop-co'ck being removed without exposing the salt to the air, a glass tube of four-tenths of an inch in diameter, previously fitted by grinding to the neck of the flask, was inserted, its open extremity dipping in quicksilver, and the flask being surrounded with sand in an iron box, was placed horizontally on a chafing dish, and fuel gradually introduced, so that the heat applied was slowly raised. In a short time moisture appeared in the tube, at a little distance from its insertion into the flask -, this increased, proceeding to a greater extent along the tube, and condensing in globules perfectly distinct, which, at different periods of the experiment, covered the inner surface for a length of three, four, or six inches -, and a small quantity col- lected at the under part, which, with a very slight inclination of the tube, moved slowly onward. At length the salt sub- Water was ob- limed, and condensed in the tube close to the flask. The quan- fuinetdlulz* tity of water, Dr. Hope was satisfied, appeared considerably fourths of a larger than in Sir Humphry's experiment. The same quan- firain > tities WATER IN MURIATIC ACID GAS. 267 tities of gases had been employed as in that experiment, and I need scarcely say, that every precaution had been taken to exclude every source of fallacy. Some of the salt having reached near to that place of the tube where the dew was con- densedj part of the moisture seemed to have been resumed by it during the cooling of the apparatus, and prevented Dr. Hope from ascertaining with precision the quantity of the fluid. To obtain an estimate of it, he next day put a little water into ano- ther flask having a similar tube, previously weighed, fitted to it by grinding, and applied heat to the flask till the inside of a portion of the tube was covered with dew, and a drop of water collected in the bottom, as in the preceding experiment. The quantity of humidity, thus condensed, weighed one grain, and in appearance so far exceeded that observed in the tube in the experiment of the preceding day, as to lead tothe.conclusion, that thelatter could not be estimated at more than two-thirds of a grain. Such is the result of these experiments intended to be deci- ^^^in-^8 siveof the question with regard to the state of the fact, whe- edbySirH.D. ther, when this salt is heated in close vessels, any water is ob- f"d, estJV i <• ■»*■ ^ <-<* \ . i bhshes the tamed from it or not. Messrs. Davys affirmed, in the most author's state- explicit terms, that there is none ; Sir H. Davy " did not ob- ments, &c. serve the slightest traces of moisture in making the experiment on a larger scale in exhausted vessels." And Mr. J. Davy found, that " no water was produced — not even the slightest trace appeared." I affirmed, that though this mode of con- ducting the experiment is unfavourable to the result, and is not at all calculated to afford information with regard to the real quantity which the salt yields, still a sensible portion of water is obtained. It is now established, that my statement is correct, that of my opponents the reverse. In the experiment, as performed by Sir Humphry himself, a sensible portion of water appeared, and when the obvious sources of fallacy at- tending that experiment have been avoided, a larger quantity has been obtained. To obviate the conclusion which might be drawn from this Remarks. The result, Mr. J. Daw endeavours to show, that the quantity ob-"wpfvUr m *" tained in his brother's experiment might be derived from extra- riment did not neous sources, from vapour in the gases, or moisture from the comt fx0m ex" ' r & * . traneoua mercury. This it is scarcely necessary to discuss. Dr. sources. Henry, he remarks, found that ammonia obstinately retains aqueous vapour, yet Dr. Henry ■ states, that ammonia may be T2 so 46f WATBA Itf MtrRIATtt AClfc GAS. id far desiccated by exposure to potash, " as to shew no traces of condensed moisture when exposed to a cold of 0° of Fahren- heit," and this precaution of exposing the ammonia to heat had been observed both in Sir Humphry's and in Dr. Hope's experiment. His brother, he adds, has proved, that a minute portion of solution of muriatic acid in water may be obtained by intensely cooling the gas. Dr. Henry, however, found, that muriatic acid gas, when freed from visible moisture, which it is completely by exposure to muriate of lime, (a precaution observed in the above experiments) deposits no water even when cooled to 26 below 0° of Fahrenheit, and Gay Lussac not only obtained the same result, but farther found no indication of moisture from the action of fluo-boric gas, which is its most delicate test. And, even according to Sir Humphry's statement, the quantity of liquid deposited from 200 cubical inches at 7 5°, cooled to 1 0 below 0, is not equal to ^ of a grain, and only about half the weight of this is water. If any such water, therefore, is taken up by the gas at 50°, and retained by it after exposure to muriate of lime, of which there is no proof, but the reverse, it may amount, in QO cubic inches, to ^ or -fa of a grain. Lastly, Ihe mercury had been strained through If the salt warm linen, and was perfectly dry. The gases, therefore, hav- wmtCT*itwOttkl mS ^)een suom^tted carefully to processes which are known to retain it, &c< render them free from all moisture, being transmitted through dry mercury, and combined in an exhausted vessel, so that the mercury never came into contact with the salt, there is not the slightest reason to suppose a communication of water from any extraneous source. It is an obvious reflection, too, that if this salt is otherwise entirely free from water, as the new hypothesis assumes, were a minute portion communicated to. it, it must be retained, in conformity to the'law which univer- sally regulates the combination of water with saline substances, by a very powerful attraction, so that it could not be expelled, and rendered sensible in such an experiment. And lastly, such causes are assigned by Mr. J. Davy only as " tending to account for the \ety minute quantity of water obtained" in his brother's experiment. They are, of course, still less adequate to account for the larger quantity in Dr. Hope's experiment -, and are utterly incapable of accounting =for the much larger quantity admitted by them to be obtained when the salt is heated in com* WATER IN MURIATIC A^ID GA$. 26J9 communication with the atmosphere, and which, it will be shewn, is derived from the salt, and not from the air. Mr. J. Davy farther contrasts the small quantity of water obtained from the muriate of ammonia in his brother's experi- ment with the quantity which, according to the common doc- trine, it contains ; this latter quantity, he seems to imagine, ' ought to be procured j and, since it is not, he concludes that that doctrine cannot be maintained. Any discussion with regard to the quantity of water obtained This kind of by heating the salt in a close vessel, is probably superfluous. cui^tedto C*" That kind of experiment I never considered as one calculated showthequag^ to afford a proper indication of the real quantity which the ^4 salt yields. I repeated it merely because Messrs. Davys affirm- ed, that there is no appearance of water whatever. That as- sertion is now proved to be incorrect, which is all that the repe- tition of the experiment was designed to establish, and the original mode of conducting it I consider as the one which gives the true result. It may be remarked, however, to obviate any difficulty from Elucidation this point, even with regard to the quantity obtained in the £ron] vari°»** more favourable mode of conducting the experiment, that the combination of muriatic acid gas with ammonia, was not re- garded as adapted to determine the proportion of combined water in the acid gas ; for, of all the combinations of this acid, it is the one in which there is the greatest difficulty in separating the water. Acids, in combining with salifiable bases, retain the whole, or the greater part of their combined water, espe- cially when these bases have also an attraction to water. To expel this from the compound salt to any extent, a heat, equal or superior to ignition, is in general required j and, by the most intense heat, it does not appear, that the whole quantity is expelled. Berthollet has shown, that after exposure to the violent heat of a forge, salts retain water, so that when again exposed to heat in mixture with iron filings, they afford hydro- gen gas ; and this is the case even with those which appear to have little attraction to water, as sulphate of barytes. Where the salt, therefore, is volatile, such as muriate of ammonia, the expulsion of its water must be imperfectly attained. The degree to which the heat may be raised is not great, and, in raising it, it must operate nearly with as much force on the real •alt, 270 WATER IN ^VltTRIATlC ACID GAS. salt, as on the water combined with it, and their mutual affinity must retain them in union till both are sublimed together. If other salts which are fixed, and which have a less strong attraction to water, yield it only at a high temperature, and then imperfectly, it is absurd to imagine, that muriate of ammonia should yield it at a much lower temperature, and yield it entirely. The experiment, therefore, was designed rather to prove the ex- istence of combined water in muriatic acid gas, and though (he quantity obtained may not be the whole quantity which, from other facts, there is reason to conclude, exists in the acid gas, it establishes this as much as if a larger quantity were obtained. It proves the The production of any water is incompatible with Sir Hum- existence of phry's hypothesis, and, therefore, refutes it: it is conformable water, and es- r , J r . ' . = ' ' . -i~, tablis-hes the to tne opposite doctrine, and becomes, therefore, a proof or its doctrine. truth; and for the quantity being less than that from other sa- line combinations of the acid, an adequate cause can be as- signed. The actual result, indeed, is precisely that which is to be expected, a sensible portion of water more considerable as the experiment is performed in a manner more favourable to its disengagement, but inferior to what is obtained from "" other combinations of the acid, from which it is obvious, a priori, that the water must be more easily expelled. So far I have restricted my observations chiefly to the re- sult of the experiment of heating the salt in close vessels. A point not less important, which remained for determination, is that relating to the result when it is heated in open vessels, and to the supposed fallacy connected with this in the absorption of water from the air. Whether the I had found that, in this mode of conducting the experi- ea!t absorbs ment, a very sensible quantity of water was obtained: and water from , . , . • , .. . , , . . , the air, as » this was not denied, but explicitly admitted, by my opponents. posed by Sir Mr. J. Davy, who had heated the salt in close vessels, without I ' avy* obtaining water, found, that when he n followed Mr. Murray's example, and collected the salt in the atmosphere, and intro- duced it into another retort, on heat being applied, water, in no inconsiderable quantity, was evolved, as he described." But to account for this, without admitting the conclusion subver- sive of his hypothesis, Sir Humphry Davy advanced the sup- position, that the salt absorbs water from the air during its trans- WATER IN MURIATIC ACID GAS. 271 transference from the one vessel to the other, and that this is the source of the water which it yields. A supposition so directly at variance with the known pro- This snpposN perties of this salt, required very ample proof, yet none was ^°rranted°by given of it, farther than the assertion of the salt not yielding the tacts; water when heated in a close vessel, while it affords it when heated in an open vessel, this result being stated as affording " a demonstration, that the water liberated in Mr. Murray's experiment, was not derived from the muriatic gas, but from the atmosphere." It affords, I remarked, (Journal, vol.32, p. 18/,) no proof, since, admitting even the statement with, regard to it to be correct, it might equally arise, since it is proved, that the salt yields water when it is heated without having been exposed to the air. I had proposed tjie obvious experiment by which the fact, and might with regard to this supposed absorption of water, may be une- certainednbvS" quivocally ascertained — that of forming the salt without ex- direct ex-peri- posure to the air/and then ascertaining if, under such exposure, metnt' but was it gains weight, which it must do if it absorbs water. The mode of conducting the experiment, and the results, have been already minutely detailed (Journal, vol. XXXII, p. 191.). These results, proving that no water is absorbed, Messrs. Davys have not attempted to controvert, but have rather thought pro- per to avoid repeating the experiment, though it had been urged against them, and is obviously decisive of the question — for what reason I shall not conjecture. The importance of the, fact with regard to this supposed ab- Repetition of sorption is such, both from the supposition having been intro- ^ent^itTn duced to account for the production of water from the salt, Hope : Lord and from its having led, in consequence of that, to a form of Webb Se^" 1.11 1 1 * . . ,."a*' , mmr and Mr- experiment which has rendered the investigation more difficult Eilis being pre- and more liable to error, that I was desirous the experiment se"t* . A ve.*~ 111 -i C J • 1 T 1 T-rr , , SCl AVlth WltJe should again be performed with every precaution. Lord Webb apai tures at Seymour and Mr. Ellis were present, and the principal steps of cacu ontl **** the experiment were executed by Dr. Hope. A vessel was ' selected, the interior of which might admit of a free exposure to the air — it was pear-shaped, having a wide orifice at each extremity, the one, one inch and a "half in diameter, the other, one inch, its whole internal surface being equal to about 40 square inches. The orifices were closed with corks rendered air-tight 27$ WATBR IN MURIATIC ACID GA8. •ir-tigbt by cement, a stop-cock being inserted in one of them for the introduction of the gases. in which the The vessel having been exhausted, about 27 cubic inches of dried mur. ae. . . . , f. , , , , , „ and amnion, muriatic acid gas, which had been exposed for two days to dry gases were muriate of lime, were combined in it with the requisite quan- Careful exa- *'tv or" ammoniacal gas, which bad been exposed for the same mination of time to dry potash ; and an excess of ammonia was allowed balance dor^ to reraain at tbe end of tne combination. The corks, with their ing full expo- cement, were removed, and clean corks, previously fitted, were showed1 'noli- instanlly inserted. The vessel was filled with atmospheric crease, but a air, by opening one of the orifices, and introducing a tube at- loss ot weight, tached to a caoutchouc bottle, the sides of which being pressed together, and then allowed to dilate, drew out the ammoniacal gas : and to secure the change being complete, both corks were removed for a second or two. The apparatus was then placed in a balance, which, loaded with it, turned very sensibly with much less than ^ of a grain. The balance being accu. rately adjusted, the corks were removed from the orifices, and . x placed beneath the vessel, and the progress .of the experiment was observed. At the end of five minutes there was no per- ceptible change, of ten minutes no change, at fifteen minutes there was, if any thing, a loss of weight on the side of the salt, at twenty minutes this loss was apparent, and amounted to about ^l of a grain, at twenty-five and at thirty minutes it remained the same. Though from the form of the vessel, and the size of the apertures, the air had the freest access to the salt which encrusted the interior ; yet, to leave no doubt, the internal air was changed repeatedly by means of the caoutchouc bottle. At forty minutes there was again the appearance of loss of weight in the salt, at fifty minutes this amounted to something less than ±Q of a grain, in addition to the former loss. The air within the vessel was again repeatedly changed, both by means of the caoutchouc bottle, and by propelling the external air through it by the motion of the hand, and by the bottle, held at a distance and slowly compressed j but for half an hour longer there was no perceptible variation of weight*. This * In a preliminary experiment which I had performed, and in which the sail was freely exposed to the air for three days, the loss of weight WATER IN MURIATIC ACID GAS. 278 This experiment was performed in the same apartment in which my former experiments had been executed, and the air was at the same temperature of 60\ It is perfectly decisive in proving, that the salt absorbs no water from air in a common state of dryness and temperature. As much of the salt was collected as could he removed from A portion of the vessel : it weighed 23*5 grains. It was introduced into a th,s monate g* ,..,,.., . 11 ammonia, be- small retort connected with a small globular receiver, and the ing exposed body of the retort being in part surrounded with sand, heat t0 liear> Save was applied by a lamp. A little of the salt suddenly rose in vapour into the neck of the retort. Afterwards moisture con* densed beyond the salt where the neck was kept cool ; the heat was slowly raised until the salt was sublimed into the top and beginning of the neck of the retort. The sand bath was then removed, a chaffing dish was applied, and the heat continued for half an hour. In the course of the experiment, the moisture increased, and extended over about one inch and a half of the upper side of the neck of the retort, where the cold was applied. The half of this space next to the bulb appeared quite wet, being covered with compressed globules of water of a considerable size, on the remaining part the globules were very minute. I formerly related an experiment in which muriate of am- More water monia, after it had afforded a portion of water at a low heat, inferred to was sublimed through ignited charcoal, to ascertain if, by the parated in an higher temperature, and by the chemical affinities exerted by ?XP- **n charcoal, an additional quantity might be abstracted. Portions of carbonic acid, and carburetted hydrogen gases, were accord- ingly obtained ; and a quantity of water was condensed. This latter result led to the conclusion, that the high degree of heat had produced a more perfect separation of the water, and that, therefore, if such a temperature were applied to the salt alone, more water might be obtained from it than by an inferior heat, while any supposed source of fallacy from the presence of the charcoal, might be avoided. was apparent to a still greater extent than in the above experiment. , Such a result, with regard to any other salt, would be ascribed to the abstraction of water by the agency of the air ; and I see no reason why the same conclusion should not be drawn with regard to it. At the end of a week the salt remained perfectly dry* A fact £74 WATER IN MURIATIC ACID GAS. Common sal- A fact I had ascertained promised to afford a ' satisfactory ftsTrsfpoVhaS mode of verif>inS this- The common sublimed muriate of tion of water ammonia, or sal-ammoniac, I had found, yields no water when roanufkctorthe exPosed to a neat sufficient to sublime it. This is owing to its and does not mode of preparation — it is first dried, then sublimed, and, afterwards at- during the sublimation, the upper part of the vessel is kept hot, to render the sublimed mass sufficiently dense, its orifice being also kept open, and hence all the water which can be driven off by this heat is expelled, and none is regained by ex- posure to the air (a decisive proof, if such were wanting, that this salt attracts no water from the atmosphere, since it is kept in the shops without any particular precaution. I exposed •' 100 grains of this salt in a retort to a heat sufficient to produce sublimation, but no moisture appeared during any part of the but it gives experiment. I then sublimed 100 grains of the same salt from ont another fae c\ose encj 0f a porcelain tube, placed across a furnace so as portion in an , . , . ... '.^ - ' . . fgnited tube. *° De at a re(* heat. A very sensible quantity of moisture condensed in a glass tube, which was adapted to the porcelain one, appearing not only in globules, but at length running down the tube. This proved, that water may be separated from muriate of ammonia by a red heat, which is not expelled from Exp. of sub- it at a lower temperature. I then submitted to a similar expe- theasal'tnofAdi-r'men^ the salt formed by the direct combination of its de- fect combina- ments. Very little moisture appeared previous to its actual volatilization, but when this commenced, the condensation of water in sensible globules took place j they continued to accu- mulate, and the quantity appeared obviously greater than what, judging from former experiments, would have been obtained by a lower heat from the salt formed from the same quantity of muriatic acid gas. Repetition in 1° another experiment, the salt formed in an exhausted re- an ignited tort was first heated until it ceased to afford water, and was afterwards sublimed through an ignited porcelain tube. Mois- ture was again obtained, though not in so large a quantity as when the charcoal had been placed in the tube. There is no just objection to the introduction of the agency of the charcoal, if care be taken to have it thoroughly calcined j and, as the supposed source of fallacy from the air affording water to the salt, is now proved to have no existence, there is no valid ob- jection tube. WATER IN MURIATIC ACID GAS. 27 5 jection to the result which the experiment with the charcoal affords. My preceding conclusions, I trust, are now sufficiently esta- Inference, blished, and it is unnecessary to enter on any recapitulation of ™* J^jjj * the argument. Water has been obtained from this salt both and did not when it is heated in close and in open vessels ; and no source °f f^^os^01* fallacy exists, as was affirmed by Messrs. Davys, in any absorp- tion of water from the atmosphere. They accounted for the production of water on that supposition, and it is now amply refuted, I have only a single observation to make on Mr. J. Davy's Considera- concluding remarks in his last communication, that he has " no nons reIatin5 6 ' . to personal intention of answering personal aspersions, which are only in- aspersion and jurious to the author when unjustly made." The necessity was censure, imposed upon me by assertions which he had advanced of stat- ing some circumstances connected with the manner in which he and his brother had conducted the controversy. I did so with reluctance, and only in so far as was necessary to my own vin- dication from a very intemperate attack. My observations conveyed censure, no doubt, but not aspersion -, for they were founded on facts, and these were very explicitly stated, that Mr. J. Davy might, if he pleased, enter into any explanation with regard to them. This he has not done, and the facts, I believe, he is unable to controvert. In concluding this investigation, I cannot but contrast the From areview assertions that were made, and the tone that was assumed, with of the manner the result that has been established. " At first view," said a" th^re-*6 Mr. J. Davy, speaking of my experiment of obtaining water suits were dis- from muriate of ammonia, " the result appears improbable, suggests^ that and opposed by several facts 5 and, in a very short time, I was it might, wita convinced by experiments that it was incorrect." Again, Pr0P"etv> " Mr. Davy, my brother, informed me, that he had not ob- more modest served the slightest traces of moisture in making the experi- and temperate, ment on a large scale in exhausted vessels; and assured me, that I should not, was not the salt exposed to the atmosphere." In repeating the experiment accordingly, no water was pro- duced " agreeably to my brother's result, not even the slightest traces appeared." Mr. Murray's errour," he adds, " appears to have arisen partly from too great confidence placed in the accuracy of his experiment, and partly from overlooking, that 276 EXPLOSIVE COMPOUND, that a light powdery substance, like muriate of ammonia, inde- pendent of its chemical attraction, absorbs water hygrometri- cally. Mr. Davy has informed me, that this is the case, and that muriate of ammonia so made, absorbs so much, that it even deliquesces." And lastly, " Mr. Murray's confidence in his result, which is opposed by several facts relative to muriate of ammonia, is to me more surprising than the result itself." When assertions and conclusions have been advanced in thil unqualified manner, which the result of investigation proves to be wholly incorrect, it is but justice to recall them for a mo- ment to notice j and when such a style of controversy has been indulged in, it is not uncandid to suggest the reflection, how much more becoming would have been a more modest and tem- perate tone. I shall refrain from farther animadversion on a topic ungrateful in itself, and too unimportant to claim any protracted discussion. With the highest respect, I remain Your most obedient Servant, J. MURRAY. r V. On the Explosive Compound of Chlorine andAxote. (Concluded from p. 190.) To Mr. Nicholson. SIR, N conformity with our promise made to you in our former communication, we resume the account of our experiments with the explosive compound. Globule of the A gloDule or" tne compound was placed under water, between compound ex- the ends of two platina wires, coated with glass excepting the water tovoT- Pomts i one of tnese wires communicated with the positive, taiam. and the other with the negative end of a voltaic trough, con- taining 50 pairs of six-inch plates, excited by weak muriatic No effect nn- acid. The globule appeared to be little, if at all, affected by cumstoncoT the current of the electric fluid, of which, we are inclined to believe, it is not a conductor : small bubbles of gas rose from it occa- Explosive compound. 277 (occasionally, but as the water with which it was in contact was undergoing rapid decomposition, it is not unlikely that these bubbles were not caused directly by the electric fluid, but by the hydrogen or oxigen liberated from the water, acting on the » compound. This source of ambiguity would be removed, if the compound could be electrised without its being in contact with any fluid ; but its extreme volatility presents an obstacle to such an arrangement, which we h^ve not yet surmounted. Having made a number of experiments for the purpose of Phenomena ascertaining generally the phenomena resulting from the contact pr0J [uctedf ty of various substances with the explosive compound, we have explosive made out the following table, in the first column of which are c°mPouna\ ,, . . ° i»,.i ,. and various stated the several substances employed, and in the second the substances. apparent effects of them on the compound. It is proper to remark, that water was always present in these experiments, the general method of making them having been to place a globule of the compound in a small iron ladle filled with water, and to bring the substance, whose action on it was to be tried, into contact with it at the bottom j but in those cases in which it was desirable to have as little water present as possible, we have substituted for the ladle a little paper filter, containing the compound and water, and allowed nearly all the water to drop through, before we added the substance to the compound. This was our mode of operating with ether, alcohol, &c. Table of the apparent Effects of certain Substances brought into Contact with the explosive Compound. Substances brought into contact with the compound. Mercury Copper .< t. -."« Tin .. .. Zinc Sulphur * Liquid sulphuretted hydro- gen, or alcohol of sul- m Phur • • ■ Super Sulphuretted hydro- gen formed by adding hy- drogUretted sulphuret of potash to muriatic acid. „ Effects observed. Slight effervescence, the me- Effects of sub- tal slowly tarnished. stances do. do. brought into tj „ contact with £ one' the explosive None. compound. None. None- Violent explosion. Do. 278 EXPLOSIVE COMPOUND- Effects of sub- Substances brought into contact stances brought into contact with the explosive coiupouud. with the compound. Do. become solid by keeping. Native sulphuret of antim. Red sulphuret of mercury. Phosphorus Pbosphuret of lime Phosphorus dissolved in li- quid sulphuretted hyd.. . Charcoal Jet Cannel coal Residuum of the distillation of amber Asphaltum Elastic bitumen .. T. ',, Elastic gum, or caoutchouc. . Resinous matter found in HighgateHill Common resin Shell Lac Copal Sandarach Mastich .. .. .. .. Euphorbium Guiacum Assafcetida . . , . . . Opium Burgundy pitch Balsam of Tolu , . . . Resin of ox bile Myrrh Scammony Frankincense Ammoniacum .. .. ,. Hepatic aloes Alcoholic solution of resin • . Do. of resin of lac . , Effects observed. Union, but no explosiou . None. None. Explosion extremely violent. Violent explosion. Do. None. None. Adhesion, slight efferves- cence. * Effervescence, film on the surface of the water. Union, rapid effervescence, ascent to the surface of the water, film left there. Union. Violent explosion. None. Effervescence. None. Union, effervescence, ascent to the surface of the water, film left there. Adhesion. Same as with copal. Do. do. Do. do. Do. do. Slight effervescence, film on the water. Un ion, effervescence . Do. do. rapid, film on the water. Slight effervescence. Explosion. None. Do. Do. Do. Rapid effervescence. Do. Cam* EXPLOSIVE COMPOUND. 2*79 Substances brought into contact with the compound. Camphor Phosphurretted camphor . Sulphuretted do. . . . Wax . i Spermaceti . . Adipocire Butter Palm oil Do. saturated with chlorine, which made it white and semifluid Oil of mace .... . Ambergris . . . . . . . Hogs' lard Whale oil . . Linseed oil Olive oil Do. do. saturated with chlorine' . . . . . .. . Do. do camphoretted Do. do. sulphuretted . . . Do. do. thickened by boil- ing on oxide of mercury. Effects observed. Effects of sub- stances 1 " ■ brought into Union in considerable quan- contact with tity with the compound, the explosive which preserves its usual colnPotmd- colour ' and appearance. When the camphoretted compound rises to the sur- face of the water, it covers it with a film of camphor, the explosive compound es- caping from it. The cam- phoretted compound in- flames without explosion by phosphorus and by essential oils. Sulphuric ether separates the camphor from it. It may be formed at the same time with the explosive compound, by introducing a bit of cam- phor into chlorine gas over solution of muriate of am- monia. Explosion. Union. None. None. None. None. Explosion. Union. Do. rapid effervescence, film on the water. Explosion. None. Explosion, separation of car- bon. Explosion. Do. separation of carbon. Union. Violent explosion: Do. Effervescence, explosion. D* 280 Explosive compound, Effects of sub- Substances brought into contact stances with the compound. brought into "" *• contact with Olive oil, by boiling on cor- the explosive rosive sublimate .. empound. on from 60ap by 8Uiphuric acid . . k Do. do. by nitric acid Oil of turpentine . . . . . . Do. do. cat. with chlorine Oil of tar. * Do. of amber Do. of petroleum Do. of Benzoin Do. of orange peel . . ♦ . Naptha Alcohol Sulphuric ether Nitric ether Phosphuretted ether Soap of potash . . . . . . Do. of soda (curd soap) Do. of do. (Castille) .. .. Do. of barytes (from nitrate) Do. of alumine (from sul- phate) Do. of lime (from nitrate) Do. of strontia (from do.) . . Do. of magnesia (from sul- phate Do. of silver (from nitrate) Do. of protoxide of mercury (from nitrate.) Do. of peroxide of mercury (from nitrate.) Do. of copper (from nitrate.) Do of lead (from nitrate.) Do. of do. (litharge plaister.) Do. of tin (from muriate.) Do. of cobalt (from nitro- muriate.) #. Effects observed. Union. Union, effervescence, film on water. Do. brisk do. film on water. Violent explosion. Union j by the application of flame to it on the surface of water, it deflagrates, and leaves a resinous look* ing substance on the water. Violent explosion. Do. Do. Union, effervescence, remark- able change of colour to blood red. Violent explosion. Rapid effervescence, explosion. None. None. None. Violent effervescence. Rapid effervescence. Union, effervescence, film or water. Do. Do. Do. Slow effervesence. Much effervescence. Slow effervescence. Do. Do. Do. Do. Violent explosion, blue flame. Do. Do. whit© flame- Do. Do. Do. Do. Do. Do. Do. Do. Effervescence. Do. Do, EXPLOSIVE COMPOUND. 281 Substances brought into contact Effects observed. Effects of sub with the compound. stances Effervescence rapid, film on brought into Soap of platina (from nitro- contact with the explosive muiiate.) ... water. compound. Do. of manganese (from sulphate.) Violent explosion. Sugar , None. Manna . . .... None. Gum Senegal . . \ None. Starch None. Indigo None. Kino None. Catechu or terra japonica. None. Extract of logwood. None. Benzoic acid None. Albumen (dried.) None. Prussiate of iron None. Triple Prussiate of potash in - None. crystals None. Nitric acid . . ... None. None. Phosphorous acid. None. Fused potash pure Explosion, owing to the heat produced by the potash dis- . solving in a small quantity of water. Effervescence. Solution of pure ammonia. Violent explosion. water Rapid effervescence. Lime Effervescence. Carbonate of lime Do. Red oxide of lead Do. Nitrate of silver Muriate of silver formed, the compound disappeared. Hidrogen gas The compound disappeared immediately, the volume of the gas increased. Super-carburetted hidrogen, The compound disappeared or defiant gas immediately. Phosphuretted hidrogen gas. Do. with explosion. Sulphuretted do. do. Do. opacity in the gas, preci- pitation of sulphur. \ Arseniuretted do. do. Do. precipitation of arsenic. Oxigen gas Do. Vol. XXXI V.— No. 15Q. U *Si EXPLOSIVE COMPOUND. Effects of sub- Suh#tances brought into contact - brought into contact with »ho explosive compound. Remark upon the table, and the general effects. with tlic explosive compound. Azotic gas. Atmospheric air. Nitrous gas. Effects observed. Do. precipitation of arsenic. Do. Do. violent explosion, blue .flame. Combustibles act most strongly on the compound. The effects ap- pear to arise from dense chlorine. Camphor, &e. ynite without decomposi- tion. No action with saturated bodies. Animal sub- stances have l;**s action than vegeta- ble. Soaps, by double de- In performing the experiments, the results of which are stated in the preceding table, our intention was not to investi- gate minutely the changes produced in the substances made to act on etch other, but to acquire a knowledge of the principal and most obvious effects of the explosive compound on a va- riety of bodies. This, we trust that we have accomplished ; :'.nd, in so doing, have discovered some curious and interesting facts j amongst which the following appear to be most deserving of notice. 1st. The class of bodies which act on the explosive compound with the most energy, are those which are termed combustible bodies. There are, however, some few exceptions to this re- mark, instanced in the want of action of ether and of alcohol. 2d. That (here is a considerable analogy between the action of the explosive compound, and that of the chlorine and eu- chlorine, separated in a condensed state by strong sulphuric acid, from the salt, known by the name of the oxymuriate of potash j which, like the explosive compound, inflames volatile oils, caoutchouc, phosphorus ammonia, &c. And that most of the effects of the explosive compound are attributable to chlorine in a condensed state, and in weak chemical union. 3d. That" there are some combustible bodies which will unite without decomposition, with the explosive compound, of which camphor is a remarkable instance. 4th. That when a combustible body is previously saturated with chlorine, its action on the explosive compound is either annihilated or much weakened. 5th. That animal substances in general appear to act with less energy on the explosive compound, than their analogous vegetable substances. The want of action of adepocire, of spermaceti, of butter, and of lard, are striking proofs of the truth of this assertion. 6th. That there is a remarkable difference in the actions on the compound of the several soaps formed by douhle decom- position EXPLOSIVE COMPOUND. 283 position of saline solutions, and solution of soap j as it ap- composition, pears that the earthy soaps do not explode with it, and that of p|0(je# the metallic soaps, those prepared from nitric salts explode, while those prepared from muriatic salts do not. Of the numerous experiments, of which a statement is given The cxperi- in the preceding table, we will not pledge ourselves that all nu Ilts JJJJJ" m are equally accurate j we have taken considerable pains that vary ourepe- they should be so, but their number has hitherto prevented us tlUou- fiom repeating the greater part of them. The repetition of some of them has convinced us, that very minute circumstances will sometimes cause the results to vary. Should we hereafter find it necessary to correct any involuntary inaccuracies in our statement, we shall do it with confidence in the indulgence of the readers of your Journal. As it may be expected, that we should describe our mode of Apparatus for .... ,. .. ., a j exposingthe bringing the explosive compound into contact with confined c011]pOuntj to portions of the gases, we have represented our apparatus for gas in a closed this purpose in the sketch, plate VI. fig. 3, to which the pre- sent explanation will apply, (a) A small capsule of bone or ivory, having a small hole in its centre — this capsule is suspended by a string, passing air-tight through the top of a glass receiver (e) between a collar of wetted leather, which serves to secure in its place the stop-cock (b) — this stop-cock has a connecting screw, to which the stop-cock (c) of the bladder (d) can at any time be attached. (/) is a water bath. When this apparatus is to be used, the capsule (a) is to be and method of drawn down, so as to bring it on the outside of the glass re-11511^1*- ceiver : the bladder with its stop-cock is to be unscrewed and filled with the gas intended to be used ; the stop cock (b) is to be opened, and by the action of the mouth applied to it the water is to be drawn up so as to fill the receiver. The cock (b) is then to be shut, and the cock (t) with the bladder of gas screwed on. A small piece of blotting paper is then to be laid on the hole in the capsule, on which the globule of the explosive compound is to be placed. The capsule is then to be placed again under the receiver, and by means of the string on the outside, drawn up into the receiver full of water, to such a height as may be thought necessary ; after which, the two stop-cocks are to be opened, which will admit the air from , the bladder into the receiver j the water in which will all de- ll 2 scer.d 284 KXPLOSIVE COMPOUND. scene! as the air enters, excepting what is retained in the cap- sule, and which covers the globule of the compound j but as this small quantity very quickly filters through the blotting paper, and falls in drops through the hole in the capsule, the compound is left exposed to the gas, and the effects of this exposure immediately appear. When the In our former communication we mentioned that the com- ke'TwJth wa- Pounc^ ma)' De preserved for any length of time, in small tubes ter in a sealed hermetically sealed, provided that the quantity of water, or of tube, it be- j inciuded with it, did not exceed seventeen times its bulk: comes dissolv- ' .,.,,,. . , , ed in process we have since found that this is strictly true, only when the ot time, link ss % quantity of water in the tube is very inconsiderable compared the quantity ot,y ..,,,/• , , i . • i water be hv to that of the air included j for that when the tube is nearly considerable. fi]ie(i with water, the compound, after some months, disappears and is dissolved in it. Remarks on jn tne same communication we described an analysis of the si urees of - , . . . . . . . eirour in the compound, remarking, at the same time, that not having re- former analy- peated it, we could not place any confidence in its results, and that our principal object in giving an account of it was, to show an easy and practicable mode of analysing the compound. In the interval, sinc,e that was published, we have paid particular attention to that analysis, and have found that there were two very material sources of error in it 5 the first was owing to the imperfect means which we then possessed of obtaining two The globules globules of equal weights -} and the second, to a circumstance of of the com- which we were not then aware (but which our subsequent ex- unequaT^and periments have proved to have a considerable influence) too much wa- vjz. that the quantity of water with which the explosive com- flent*VaS Pl°" Pound was ,n contact when it was decomposed by potash, was much too large, and occasioned less azotic gas to be given out, than would otherwise have been collected. To obviate these two sources of error has been the object of our recent labours, and we have fortunately succeeded in removing both. Remedv. The The mode by which we have succeeded irt always operating exact measure vvith known weights of the compound, is by using a glass sy- poimd waaas- r,nge* ot the f°rra represented in fig. 4. pi. VI. the lower part curtained by a of which terminates in a tttbe of small bore j such as is used capillary sy- ^or thermometers. This tube is graduated on the outside into inches and decimal parts, and when the point is placed in a globule of the explosive compound under water, and the piston raised? EXPLOSIVE COMPOUND. 285 raised, the compound may be drawn up in an uninterrupted line to any mark on the stem that may be desired : the inch measure of the stem of our syringe holds exactly 53 grains of pure mercury 5 consequently it must hold 625 of a grain of the explosive compound, the specific gravity of mercury being 13 568, and that of the explosive compound, according to our experiments, being 1*6. The mode by which we obviated the errour arising from having much water present, was to decompose the compound over mercury in the following manner : A small stoppered phial was converted to an air receiver, by and the quan- having its bottom cut off — it was then sunk up to its neck in f"v of watei* . , . „ • , , , taken very the mercury contained in a small mercurial trough, the stopper small, over being first taken out. The capacity of the neck was then mercury, filled with a few drops of water, into which was introduced the '625 of a grain of the explosive compound — the glass stopper was then put into its place, and the receiver, with its contents, raised on to the shelf of the trough. Some potash was then procured, which was free from carbonic acid, and had been deprived of any combustible matter, by having undergone igneous fusion j it was also free from any metallic oxide. Of Solution of this potash a concentrated aqueous solution was made, and mis Potasn *d«cd> solution passed up into the receiver to the compound, the de- composition of which it occasioned. In performing this expe- riment, it is of importance not to pass up the fused potash in the solid state, as the heat which is occasioned by its solution in the small quantity of water which it meets with, instantly causes the compound to explode. The decomposition of the compound by liquid ammonia we or of ammo- effected exactly in the same manner, passing up the solution ma* of ammonia instead of the solution of potash j the solution of pure ammonia must, however, be diluted with its own bulk of water, otherwise it will immediately occasion an explosion of the compound. By these arrangements, we believe that we have removed The analysis every source of error j and, having repeated the analysis several en"ft™j t^1S times with the greatest care, and with scarcely any variation confidence, in the quantities of gases obtained, we are enabled to give those quantities with considerable confidence. This will be best done by stating the particulars of two of our experiments. Ml 286 EXPLOSIVE COMPOUND. Exp. 2. De- composition by ammonia. Exp.i. Dv- 1st Exp. (Barometer 304, thermometer 55°) '625 of a by potash?11 gram °f the explosive compound was decomposed by solution of potash, in the manner just described j the quantity of gas obtained was '25 of a cubic inch ; phosphous was sublimed in it ; after which operation, and being again cooled, its volume was 245 of a cubic inch ; which being phosphuvetted azotic gas, must be corrected for an increase of volume of ^ by phosphorus in solution. This brings it to 239, which, brought to the mean temperature and pressure, becomes "2447 of a cubic inch, being the quantity of azotic gas derived from the compound. 2d Exp. (Barometer 30*4, thermometer 55°) '625 of a grain of the explosive compound was decomposed by a solution of pure ammonia, diluted with its bulk of water, in the manner before stated. The quantity of gas obtained was '395 of a cubic inch : after subliming phosphorus in it, it was *4l, which, corrected for increase of volume by phosphorus in so- lution, for pressure above the mean, and for temperature below it, becomes '4095 of a cubic inch, being the quantity of azotic gas derived both from the compound, and from* the decomposi- tion of the ammonia by the chlorine of the compound. Then to know how much is derived from the latter source only, we bave only to deduct the quantity ascertained by the first expe- riment, from that ascertained by this experiment. This being done, the remainder is *l648, which remainder, representing three times its volume of chlorine gas, gives *4944 of a cubic inch, as the volume of chlorine gas contained in 625 of a grain of the explosive compound. The quantities The quantity of azotic gas in 625 of a grain of the com- et azotic and p0Un(j Dejng ascertained by the first experiment, and that of the in the com- chlorine gas in the same weight of the compound being known pound fry tne seconci experiment, it is obvious, that if the experi- ments are accurate, and the compound consists of chlorine and azote only, then the weights of those two gases should exactly correspond with the weight of the compound, viz. *rj25 of a grain. But, according to the following calculation, this is not the case. Weight EXPLOSIVE COMPOUND. 28? c. inches. Weight of -2447 of azotic gas (Biot and Arrago) .. .. '0735 of a grain, Do. of '4()44 of chlorine gas fGay Lus- sac and Thenard) '3724 of do. Total "4459 of do. Here, then, we have a deficiency of '1791 or* a »ram> f°r are less than which we must account either by concluding that our analysis ^^ole is inaccurate, or that the explosive compound contains some other constituent part besides azote and chlorine. But from having repeated our analysis several times, we are j5nt as tne ana. convinced, that it is free from errors of any consequence : lpis was accu- we, therefore, conclude, that azote and chlorine are not the ' sole constituents of the explosive compound. What other, then, does it contain ? To answer this question t]je compolin(| we must first consider what others it can possibly contain, and must have we shall find that no others, excepting oxigen or hydrogen, component can possibly enter into its composition, because, in the simplest cases of its formation, no other bodies are present than chlo- rine, azote, oxigen, and hydrogen. Now, if it contained oxigen as a third substance, the results wnicfc does of the decomposition of the compound by ammonia, would be »ot appear to different from what we find them 3 for, in that process, the e oxlSen> oxigen must either assume the gaseous form, which it does not 3 or, if it be supposed to form water with the hydrogen of the ammonia, then it must displace five times more azotic gas than chlorine would, because any given weight of oxigen com- bines with five times more hydrogen than the same weight of chlorine does. Instead, therefore, of collecting too little azotic gas, we should have had a very considerable excess. The supposition, therefore, that oxigen is the third substance contained in the explosive compound, is, in the highest degree, improbable, and inconsistent with the results of our experi- ments. It must, therefore, be hydrogen whicli is the third substance, but hydrogen. But in whatever proportion the hydrogen may exist in the Deduction compound, it must, by combining with a certain portion of _tnat t,ie hy; the chlorine in that compound, neutralise the decomposing iJcombinaTioH action EXPLOSIVE COMPOUND. with chlorine, action of that portion on ammonia. This portion of chlorine nnanthCl1 stat* would not> therefore, be indicated in the action of the corn- ed, pound on ammonia by the separation of one-third its volume of azotic gas, it having combined with hydrogen at the expence of the compound, and not at the expence of the ammonia. In the before-mentioned analysis there xs, therefore, a deficiency of a certain portion of hydrogen, and of a certain portion of chlorine j but, as the total deficiency of both is known, (being the difference between the weighi of the compound analysed, •625 of a grain, and that of the gases ascertained by the ana- lysis, *4459 of a grain) viz. *1 /Ql of a grain ; and as the pro- portions in which chlorine combines with hydrogen are also known, (being equal volumes of the two gases, or by weight J hydrogen to 30" 148 chlorine) it follows, that the volumes and weights to be added are, c. in. grain. •23012 of chlorine gas weighing '17335 •230/2 of hydrogen gas, do '00575 Whence the With these additions to the analysis, the composition of *rj25 component 0f a grain of the explosive compound will be as follows : parts, as cor- rected, are c. in. at mean ascertained j temp, and grains, pres. 7245 chlorine gas '54575 •2447 azotic gas '07350 •2301 hydrogen gas -00575 ■ J condensed in the compound 1'1993 \ -7-fy their volume *625 or otherwise ^r *ts comP°sition may be staled in a different form, upon by a different the supposition that the elements arrange themselves in the of'the^compo- f°Ilowmg wav; tne hydrogen, with part of the chlorine, being nents. in the state of muriatic acid. c. in. at mean temp, and , grains, pret*. 4944 chlorine gas "3724 •46o2 muriatic acid gas '1791 •2447 azotic gas '0735 {condensed in the compound < — 1\1- their volume' -625 An EXPLOSIVE COMPOUND. (2 $9 An objection may be made to the above reasoning and eon- An hypothesis elusion, on the ground that we have not taken into consideration m^ 0^ "|ut C the possibility of the explosive substance being a compound of and hydrogen chlorine, azote, oxigen and hydrogen j and. k may be said, jK^fJJJjTSf that the arguments for the exclusion of oxigen from the com- water. pound, drawn from its action on ammonia, will lose all their force if it is considered as a quaternary combination instead of a ternary one ; because the oxigen and hydrogen in the com- pound may be in the state of water 5 in which case neither of them would appear in the gaseous state by the action of am- monia, nor could the oxigen displace azote from that alkali. In answer to such an objection we have to observe, that the But this qua- supposition that the explosive substance is a quaternary com- Jq™*^ is°not pound of chlorine, azote, oxigen and hydrogen, being at pre- probable, sent unsupported by experiment, we conceive that the fol- lowing reasons will justify us for refusing to admit it. 1st. It is not consistent with the cautious principles of phi- Reasons. losophical reasoning to admit four elements in a compound, so phii0sopUi? long as its properties and actions on other bodies are explicable sing, by three. 2d. From the known affinities of the four elements above- a. That such a mentioned, and from the proportions in which they must exist compound , , . , , ... would have dif- m the explosive compound on the supposition under con- fercnt proper- sideration, we infer that they must be combined in '625 of a ties. grain of the explosive substance, in the following manner : grs. •372 chlorine t c . . . ., •Oil hy-lrogen j forming munatic acid, '773 azote •083 oxigen. > forming nitrous gas, '076 oxigen 1 r •010 hydrogen j Arming water. •625 In which case the characteristic properties of the compound would be those of muriatic acid and of nitrous gas, and not those of chlorine, which is contrary to the fact. Should, however, it be proved, by satisfactory experiments, But if expe- that the explosive substance contains oxigen, our statement of "ments should . establish such ths £C)0 EXPLOSIVE COMPOUiND. a compound, the composition of that substance must be modified, by ad- |^rtd^uct^OMttio§,t)mibebfarogen4o«liecompo^ is neutralized by changed, oxigen instead of by chlorine. The hydrogen The hydrogen in the compound appears to be the link, con- uuion' necting together the chlorine and azote, by its affinities for both, in the same manner as it does in the ternary compound with chlorine and carbon, formed when snpercarburelted hy- drogen gas and chlorine gas are mixed together, and prevents It is the hydrogen in it also that, in ail probability, prevents tronTbcinw'IJe- '* ^rom DemS instantly decomposed by water, by weakening composed by the attraction between the chlorine of the compound and the hydrogen of the water ; so that it is not able to overcome that which unites the elements of the water. Instead of Sir It will be observed, that we have adopted the system of Sir orv ©rchlo-*" **• Davy, with respect to the nature of what was formerly rine, the ear- called oxi muriatic gas. The several phenomena resulting ox mor°acid ^rom l^e act*on °f tae explosive compound on other bodies, may probably however, are probably also capable of explanation on the old be applicable. ineory ; and such of your readers as may wish to apply that theory to these phenomena, have only to consider them as resulting from the transfer of oxigen from the oximuriatic acid of the compound to the combustible body, forming oxi- genised products, such as carbonic acid, oxides, &c. and to the separation of the muriatic acid from the compound; in con- sequence of this loss of oxigen. Explanation. On Sir H. Davy's system, these phenomena are considered as resulting from the attraction of the chlorine for combustible bodies, and most usually for hydrogen, which it takes either from a combustible body containing it, or from the water pre- sent j and, in these cases, the muriatic acid is formed from this union of chlorine with hydrogen j and oxygenised products are also formed whenever the hydrogen, which thus unites to the chlorine, is derived from the water. We are, Sir, Your most obedient, humble Servants, R.PORRETT, Juw. W.WILSON. RUPERT KIRK. tendon, lOlh March, 16! 3. THE COMPUTING BOY. VI. 291 Vindication of the Claims of the American Boy 'to extraordinary Talents and original Discovery, In a Letter from Mr. W. Saint. i To Mr. Nicholson. SIR, N reading your last number, I was struck with surprise (in Observations common, it should seem, with most of your readers) to and fat;t8 i". J , ; ' support or the find that you had inserted a letter from the Mornuig Chronicle> talents, and which purported to give an account of the manner by which originality of / . i r , • , , • -, i i the methods ot the American coy performs his calculations with such wonder- computing by derful celerity. Now I am persuaded, Sir, that, had you had Zcrali Col- sufficient leisure to examine into the merits of that letter, and into the claims of its author to the important discovery which he affects to have made, you would not have given publicity, (and, what is of still greater consequence, yon? sanction) to a statement so little calculated to effect the object of its author, which was " to reduce the child to what he really is— a very clever boy, but no prodigy." Your insertion of this letter, after the very excellent account you gave of the boy in a former number, has tended to produce a belief in the minds of such of your readers as are unaccus- tomed to abstruse calculations, that what this child does may likewise be effected by any other boy of good abilities, and thus a prejudice may be excited against this youthful and astonishing calculator, which may prove equally injurious to his own fame, and to his father's pecuniary interest. I have, therefore, to re- quest, Sir, that you will assist me in my efforts to vindicate the reputation of this extraordinary boy, by inserting in your next number, if convenient, the following remarks on the letter alluded to, in which I have endeavoured to show, that Mr. A. H. E. has not succeeded in discovering the method by which this boy performs his calculations with such surprising celerity. In the application of M. Ralliers method to the extraction of the cube root, Mr. A. allows, that " the result is ambiguous where the numbei proposed'terminates with an even digit, or with a 5 j" he proceeds, however, to explain how the difficulty may 292 THE COMPUTING BOY. Observations may be removed with respect to the even digit, though I think support ofthe * ma^ sa^eb' challenge him to produce a single instance of a talents, and child from six to eight years of age, who would be able to itemeth%sofCOmPre^lend the met*1 mucn less to apply it with facility and computing by rapidity. Be this as it may, it is confessed by Mr. A. that the Zerah Col- case 0f numbers ending with 5 is one which l( can deceive," and I accordingly expected to find that Mr. A. had given the boy various examples of this am biguous case, and that he had uniformly found the boy incapable of answering such questions correctly, or that he had obtained from him an a(knowledge?nent that such questions were beyond the reach of his powers to answer. Yet nothing of this kind is mentioned by Mr. A. who leaves us totally in the dark upon the very point which would have cleared up the difficulty. Are we to imagine, then, that Mr. A. though aware of the importance of putting such questions, for the purpose of ascertaining whether M. Ralliers method was employed or not, yet omitted to ask them ? Or, if he did ask questions of this kind, and received wrong answers, (which must have been the case if the boy employed the me- thod alluded to,) how is it that he has neglected to avail himself of the statement of this circumstance, so materially affecting his claims to a discovery which he evidently considers to be an important one. But allow me, Sir, to examine the merits of this rule in its application to the square root. Let us suppose the boy was. requested to extract the square root of the number 42436 , here it is obvious the first figure of the root would be 2, and the last either 4 or 6 ; — if 4 be taken, then 4 or Q would be found to be the middle figure j but if 6 be used, then O or 5 would be the middle figure j hence there would be no fewer than four different roots obtained by M. Rallier's method, of which four the boy could not possibly know the correct one, and he might assign either 20(3, 256, 244, or 2^4 for the root of the required number. This is no particular example, se- lected for the purpose of exhibiting M. Rallier's rule in the most unfavourable point of view ; for it will be found upon trial, that had any other number been proposed, four different results would have been obtained by this rule; and that if a number ending with 5 had been proposed, no less than ten different results would have been produced, since all square num- bers THE COMPUTING BOY. '293 bers ending with 5 will likewise terminate with 25, as I li3ve Observations shown in your Philosophical Journal, No. 99, where may also ^MJ J^of'ihe be seen some other curious properties relating to square num- talents, and bers. It is manifest, therefore, that, if the boy adopted this o"si«'i^y °£ , , , ' . • . the methods of method, he would not only make " many more errors in the computing by extraction of the square than in that of the cube root j" but Zerali Col- that he. would, in most cases, fail three times out of four } and, in some cases, 7iine times out of ten. Any of your readers may satisfy themselves respecting this ambiguity, by referring to a table of square numbers, where they will rind that the frst 25 square numbers contain all the varieties of the two terminating figures of such numbers j and that the squares of all numbers equally above and below 25 ; as of 24 and 26 ; or of 23 and 27, &c. will have their two last figures the same : this property may not have been noticed by your readers in general, but those of them who are but slightly acquainted with mathematics may satisfy themselves of its truth and universality -, for since the difference of the squares of the sum, and difference of any two numbers is equal to four times the product of those numbers, it is manifest that the dif- ference of the squares of two numbers of the form 25 + a, and . 25 — a, would be of the form 100a ; that is, this difference would be some exact multiple'of 1 00 j and therefore two such- squares could not differ in their units and tens places of figures 5 viz. in their two last digits ; hence, then (syice the two last figures only are used in M. Ralliers method) would arise the ambiguity which I have stated. It will be easily seen, that what I have shown of numbers of the form 25 + a, and 25-— a, is equally true of the general formulas 25w + tf and 25w— a. Having proved, that M. Ralliers rule is only of partial utility in the extraction of the cube root, and of little or no use in the square root, " I think it would be extremely unfair to conclude, that either this method, or one very similar to it is adopted by the boy. Suppose, however, Sir, that it were possible for the boy to have answered such questions as related merely to the square and cube roots of numbers by the help of the above rule, still this will not explain the method by which he multiplies four figures by four, or by which he ascertains the factors of any number, however large, with a rapidity that has astonished some "f 2Q4* THE COMPUTING BOY. Observations of the first mathematicians in the country. I am aware, indeed, smorto^to that Mr# A' refers t0 another memoir of M. Rallier, on prime talents, and and composite numbers, and I regret, in common with most of tli^^thod ^our reac'ers' tnat ne n;,s not given us so-much as a single hint of computing respecting the method employed in this second memoir, though by Zerah Col- jle savs « jt ;s probably the one pursued by the boy to find prime numbers, and to resolve numbers into their factors." Without knowing myself, however, what this method may be, I cannot think that it has been adopted by the boy, for several reasons ; first, because it has been known for nearly fifty years, secondly, that none of the mathematicians who have seen the boy (except Mr. A.) have considered any of the known methods of operating with prime and composite numbers, as sufficient to account for the rapidity with which the calculations have been performed j and thirdly, that the method itself could iuver have fallen into disrepute, but would have been adopted not only by every mathematician, but by every teacher of arithme- tic in the most obscure country villages, if it had been of such inestimable utility as to have enabled boys of only six yjiars of age to have performed such astonishing calculations . Again, Sir, Mr. A. made no new discovery when he found that the boy, in extracting the square or cube root of any pro- posed number, made use only of the two first and two last figures. This curious and singular fact had been known for many months to several eminent mathematicians who had visited the boy, and who were soon convinced, from the quick- ness and accuracy of his answers, and from the power which he possessed of correcting himself whenever he committed an error, that M.Rallier's method was not the one he employed, even in the extraction of roots, much less in ascertaining the factors of large numbers, which he does with a rapidity and apparent facility, astonishing to those who have been long ac- quainted with the method alluded to, and who, notwithstanding their years of practice in abstruse calculations, find, that they themselves cannot perform such operations, neither by that me- thod, nor by any other yet made public ! What, then, shall we think of Mr. A.'s claims to the discovery of the " modus operandi ?" Mr. A. might have spared himself the trouble of suggesting an alteration in the intermediate figures of any J erfet t 'e, h THE COMPUTING BOY. 295 which may be proposed to the boy, since such intermediate Observations FIGURES NEED NOT BE MENTIONED AT ALL j for it is Well ""^rfort Of" lie known/that, in a company of upwards of one hundred per- .talents, and sons, amongst whom were some of the first literary and scien- n»'Ki«aiky of & ' , the methods ot tine characters in the kingdom, the following question was dis- computing by tinctly and unequivocally put to the child. — " Can you tell the derail Col- mot of a perfect cube number by means of the two first and two last digits only ?" He answered " Yes :" and that the company might be satisfied that he clearly understood the na- ture of the question, it was put to him again in the following manner : " If a number of 12 figures be taken (which shall be a perfect cube) and the two first and the two last figures only be named to you, can you tell the cube root of the whole number ?" To this he also replied, Yes. He was then tried by various examples, which he answered with a facility and correctness that excited the wonder and admiration of every one present. Now, Sir, was there in all this any appearance of a wish to deceive ? any desire to conceal any thing ? any fear expressed by the boy lest the various questions which were put to him might lead to a detection of his method? No, Sir, all was fair, frank, open, and ingenuous ! But I am persuaded, Sir, that what I have stated must be sufficient to convince any unprejudiced person, that Mr. A. has not succeeded in discover- ing the method by which the child performs his operations j and I am therefore led to hope that I may thus counteract the tendency which, the publication of Mr. A.'s letter in your Journal may probably have had to injure both the boyNand his father. I am, Sir, with the warmest wishes for the success of your Journal, Your most humble Servant, W. SAINT. Loiver Close, Norwich, March 13 th, 1813. vrr. METEOROLOGICAL JOURNAL. VII. METEOROLOGICAL JOURNAL. Barometer. Thermometer, j 18 13. Mo. Wind. Ma\. Min. Med. Max. Min. Mod. Evap. Rain 1st Jan. 24 N "E 30-46 30-37 30415 37 24 30*5 < 25 N E 3047 3045 30*460 36 29 325 26 N E 3048 30 40 30440 41 35 380 20 N 3049 304/ 30-480 39 21 30-0 2 Var. 3039 3037 30-380, 32 20 260 2 Var. 3048 3039 304351 34 21 26-5 3 N W 30.48 3044 30460 42 30 360 31 N W 30-501 3044 30470 48 34 410 0 27 2d Mo. Fib. 1 Var, 3033 3024 30*285 41 30 355 • 2 N W 3037 30-32 30245 41 36 38'5 3 N W 3045 30 37 30410 43 34 385 4 W 3045 30-29 30370 41 34 37*5 5 s 30 29 29-78 30*035 47 36 415 6 s w 2989 29-78 29*835 47 38 42*5 7 s w 29 98} 2979 29 885 48 37 425 8 s w 2966, 2963 29645 52 44 480 G 9 s w 29-88 2966 2977O 51 35 430 036 10 w 3000; 29-88 2O*940| 46 33 39-5 *11 s 30-00.' 29-75 29875 47 35 41 0 12 s 2975J 29-28 29*515 56 44 50'0 13 s w 2948; 2937 29*425 57 39 48 0 033 14 s w 2938J 2927 29*325 52 42 470 030 15 s w 29-34; 2927 29*305 52 41 46*5 018 (i. 16 s w 2944; 2934 29*390 48 41 445 17 s w 29'3/i 29-30 29335 52 43 475 a 27 18 s w 29-88; 20-37 29*625 52 41 46*5 19 s 2966 296O 29'630 56 40 480 019 20 s w 298OJ 2966 29730 53 42 475 21 s w 29 70J 2969 30 50 2927 2g-6gs 57 49 530 190 29957 57 20 4058 The observations in each line of the table apply to a period of twenty-four hours* beginning at 9 A. M. on the day indicated in the first column. A dash denotes, tha* the result is included in the next following observation. METEOROLOGICAL JOURNAL. 297 REMARKS. 1813. First Month. 24. light clouds and sunshine. 28. Rime on the trees : very misty a. m. clear p.m. 2Q. Hoar frost : the sky overcast. 30. Misty to the S. a.m. A grey day. 31. Misty a. m. Hoary Cirrostratus clouds : rain at night. Second Month. 1. The Cumulostratus, which has not for a longtime been exhibited, appeared to-day in large masses. 7. Showers and wind : at sun-set, several large clouds of the modification Nimbus. 8. Stormy. 9. A violent thunder gust from the west about 2 p. m. by which considerable damage wa3 done to the roofs and chimnies of houses, &c. This was fol- lowed by a series of heavy gales (continuing with a few short intervals of calm and pleasant weather) to the end of the pe- riod. The lunar halo appeared before several of these, of a large diameter j and, on the 18th, about 11 a. m. there was a brilliant rainbow. The river Lea has considerably inundated the adjacent lands. RESULTS. Winds, in the fore part, northerly, with a very dry, dense air, and low temperature : in the latter part, southerly, with a rare and moist atmosphere, and high temperature. Barometer : greatest observed elevation, 30*50 in. j least 29* 27 in. Mean of the period 29*957 inches. Thermometer: highest 57° • lowest 20° -, Mean of the period, 40*58.° Rain 1*90 inches. The current of evaporation has been again interrupted, and is there- fore omitted, in order to be resumed in next report. These observations will be continued at Tottenham, Middlesex, to which pluce the observer has removed his residence. Tottenham, Second Month, 23, 1813. Vol.XXXIV.-Nq. 139. X Via 2<)8 SHOOTING-STARS. VIII. On the connection letween Shooting- Stars and large Meleors,a>d proceeding both from terrestrial and saiellitula, in njoindr to Mr. G. J. Singer. By Mr. John Farey, Sen. To William Nicholson, Esq, snt, Phenomena TT) EING in the North of Scotland at the time that your stars°and u"ie **^ September number appeared, and not having leisure and means of opportunity since to consult the same until now, I should not Siem^&c* otherwise have delayed so long to reply to your correspondent Mr. G. J. Singer, were it only to repel an insinuation with which he concludes, viz. that I had in my 2nd letter to you on shooting stars, exulted in your valuable correspondent, Mr. Forster, having been deterred, or in his discontinuing to give his 'f accurate observations" of meteorological phenomena. Accurate and sufficient observations on the phenomena of nature I am ever desirous of seeing multiplied as much as possiblej not so I confess, those that are so loosely or incompletely made or recorded, as to lead only to 'the support of what I con- ceive to be a false hypothesis. I have elsewhere and repeatedly recommended the multiply- ing of observations on shooting-stars and meteors, of a nature which does not seem to have occurred to Mr. S. viz. by two or more observers, at several miles distant from each other, each having a well-regulated watch, and a person stationed to read off, and record the observations made, in or near to some con- stellation previously fixed on by the observers, during a certain time each night, through a long period, the place, direction, and length of course, being recorded by each, with reference to a good planisphere of the part of the heavens fixed on, with which each observer is; furnished ; the comparative velocity, brightness, interrupting clouds, haziness, light of the moon, &c. &rc. being recorded by each observer. From a pretty complete series of observations thus conducted, in conjunction wirh my able friend Mr. Benjamin Bevan, now the engineer to the Grand Junction and other canals, and recorded during an hour at least,and oftener twoor three on my part, resumed in SHOOTING -STARS. 299 in every evening for more than a year ; I am compelled to dissent Phenomena from some of Mr. S \s facts respecting these phenomena, and gtars°and tiie entirely so from his manner of accounting for them, by electri- means of city, an agent which we well know was in fashion a few years tiieu|1V&^ ago, for explaining a great variety of phenomena. My observations, above alluded to, decidedly prove, that all which ought properly to be called shooting-stars, having only a short and rr.pid course, and bet a sm 11 apparent size, appeared only when the air was clear rind cloudless, in the place of observa- tion, and when only a very small degree of extraneous light prevailed , and that the calculated place of many of these, from the best of our concurrent observations, made at 6 miles distant,shewing them to be at 60 to J (30 miles distance from us, and at 40 to 50 miles of perpendicular height above the earth's surface, seemed exactly to accord with the short, feeble, and unobtrusive nature of their appearances. My observations also shew, as I have mentioned, a very regular series, of what I denominate Meteors, the least of which were nearly as short, quick, and faint jn their appearances, a$ the shooting-stars, to others which were very long in their courses, slow in their motions (apparently) and with correspond- ing degrees of size and brightness, and attended by explosions and sparks, and small trains, some of the largest of them j but none of which last ever appeared biit in clear parts of the sky : and our calculations shewed all of these last, to bd far above the height of the ordinary clouds. Mr. S. mistakes, apparently, in supposing me to have assert* ed, that the larger class of meteors are not sometimes visible on moon- light nights, and even before the day is quite closed, as I have more than once myself observed, but' never zvher*: clouds appeared at the time, as we almost constantly see of flashes of lightning, the only visible electric luminous pheno- mena of the atmosphere, perhaps. Whence Mr. S. gathered, that satellitic (not planetary or cometary) bodies, move " with immeasurable velocity," I arri at a loss to think. As Mr. Forster's authority has been referred to >(though very inconclusively, I maintain) in page 34, 1 cannot help repeating, that if that gentleman, or Mr. L. Howard, ever did, or if they sow concur with Mr. S. as to the shooting-stars being an ' X 2 electrical 300 SHOOTING-STARS. Phenomena electrical phenomenon, they would in all probability have stars°aud8tiie resumed tne mention of them, and of other undisputed electric means of phenomena occurring at or near to the same time with them, in observing their subsequent and valuable papers or reports, in order to shew such their concurrence in Mr. S.'s opinion. I have expressly mentioned, on different occasions, that it is the largest class of bursting meteors, or those having trains of stars after them, which are accompanied by falling meteoric stones, and not the shooting-stars j " falling- stars" I conceive to be an improper name for any of these phenomena. The great comparative scarcity of meteors, and of the stars falling obliquely from them, indicative of their approaching dispersion and end, are sufficiently consistent, and prove nothing against my alleged connection of them with shooting- stars, an extremely frequent, and as I conceive, a periodical phenomenon. And here I would remark, that nearly all the meteors which I or my friends have seen, as well as the shoot- ing stars, have vanished, or ceased to appear, almost at once, in clear parts of the sky, where they passed out of the atmosphere, as I conceive, and have not passed behind clouds, as has very commonly been said, in newspaper and other accounts. I have not " travelled" far enough, even in theory, to have said, or even conjectured, where the satellitulce, more than the moon or large satellite of our planet, came from ; but by no means can I admit the reasonings, that they came recently from the moon's volcanos, or more anciently from a burst planet, con- jectured by some, to have given rise to Ceres, Pallas, and Juno. I entirely dissent from Mr. S.'s 4th alleged fact, at page 3(5, and from the 4th, 5th, and 6th of those at page 37, as applied tp shooting-stars. Mine is not a "planetary hypothesis," nor is it opposed, I believe, to either the facts or analogy of these, or other parts of the system of the universe, as now explained on the principles of the universal gravitation of masses, whose motions and present states are within the scope of our cogni- zance, but not their origins. I remain, Sir, Your obedient Servant, JOHN FAREY, Sen. 12, Upper Crown Street, Westminster, February 22d, 1813. HUMAN FIGURE IN ICE. 301 IX. Account of a remarkable Appearance in the Ice of a Pond in which a man was drowned. (W. N.) ON the west side of the road leading from Petworth to Local situa- Chicbester, at the distance of about four miles from that £™ J?,* 1°** city, stands Halnaker House, formerly the seat of the Earl of man was Derby, by right of his wife, heiress of Sir William Morley, and ^XaTei-1" more anciently of West, Lord de la War. On the west side of park, Sussex, the park, are certain stables, and other buildings, inclosing a farm yard j in which is a pond of about 18 or 20 feet across, and 5 feet deep in the middle. A man was drowned in this pond in the month of November last ; and the circumstances attending the discovery of his body were so curious and uncom- mon, that they occasioned much conversation at the time j but it does not appear that any probable explanation of their cause was pointed out. Very lately I was much gratified by a discussion of this Authentic subject in a select company of men of talents and observation, statement of where we had the advantage of the facts being stated by the Rev. James Webber, Chaplain to the House of Commons, who was an eye witness. The clearness and precision with which this gentleman stated the events to us, gave a much more lively interest to the whole : for the narrative in the public prints, which had appeared most remarkable for its strangeness, and perhaps liable to doubt, now assumed the form of an authentic and accurate philosophical incident, capable of being examined and investi- gated. I did not scruple to request Mr. Webber Jo favour me with such written minutes as his own recollection, or enquiries among his friends, might afford, in order that I might com- municate the same to my readers, with those deductions and remarks which, with the advantage of the conversation before by respectable mentioned, I might be enabled to make : and it is to his ready eve*wltnesses- attention to my request, that I am obliged for the following statement, which I have made in my own words from his com- munication, and those of his brother, Mr. Archdeacon Webber, Vicar of Boxgrove, and the Rev. Mr. Valintine, Domestic Chaplain to the Lord Bishop of Chichester. About the 14th or 15th of December last, the pond in The figure of a Halnaker Park, having been frozen over by the hard weather Inai) was seen on the ice ; which COt HUMAN FIGURE IN ICE. which commenced on the llth, the figure of a man W3S ob- served on the surface of the ice, and upon the event being communicated to several gentlemen in the neighbourhood, they visited the spot, and examined the circumstances most likely to indicate the cause, and its mode of operation. fcy* The pond shelves gradually down from its border to its centre, litv. Tut- ice where the depth is about five feet, and the water is discoloured of Ae figure of a reddish brown, by a strong impregnation from an was Hear, ,. . . , . . . , , . . . _ , . hard, and adjoining dung mixen which drains into it: of this transparent, colour also was the ice upon the pond, excepting that which brown, soft composed the figure. This appeared black and was very clear and impure, like the purest water, the discoloured water being visible through it j the ice of the figure was extremely slippery and hard, while the rest of the ice was comparatively crumbly Snow on the and soft. It must also be observed, that a slight fall of snow pot 'on the ^ad covered it all, with the exception of the figure, which figare. by that means became strikingly defined. But at the com- mencement of the frost, three days before, the snow was seen uniformly covering the whole pond. An opake line surrounded the figure, consisting of ice different in appear- ance from the rest, and whiter. Fig. 2. plate vi. represent* aris oi the ice which were taken out of the pond in three The ice was pieces, and laid upon the grass near its bank The body of tl™body o"tne tlie man was l(,osened irom ,ne mud at tne bottom of the inan taken up. pond' by a pitch-fork, and rose at once head foremost with the hat on. It was quite stiff and showed no signs of putrefaction. One of the arms was bent, the hand being inserted under a round Sussex frock he had on ; one of the feet pointed upwards, The figure and the other down, and the legs were straight. The figure corresponded on t[ie ice corresponded with the outline of the body excepting m situation , f 4 • , ' , with that of t! at the head in the former was terminated abruptly by a the body,— ];ne answering to the bottom of the hat. There did not appear whichhadnot ° , . , , , . , , ., . before risen. any reason to suppose the body had risen beneath the ice $ not only because it was discovered fast in the mud, but because the ice was quite flat on both sides, and of the same uniform thickness, namely eight inches. When the ice was held up to the light, the difference of its quality was very singular, the figure being clear and transparent, though greenish, and the other part foul and obscore like the water of the pond : The man's head lay: towards the south-east as was aiso that of HUMAN FIGURE IN ICE, 3tf3 of the figure, which was directly over the body. He was recognized to be a traveller or pedlar, who frequently came into those parts, and from the time of his having been missing, he appears to have been drowned on the 30th of November. This most remarkable and uncommonly curious event, led us Speculations into a variety of speculations 3 several of which were imme- wer ac{ phenomena of electricity or of heat, does or may rise., of upwards ;-* * Philos. Journal, III. 290. 304 HUMAN FIGURE IN ICE. shew its effects by a perpendicular action from beneath the surface of the ground, and is capable of being modified by changes of no great extent in what maybe lodged beneath. Ss?C1bUu? ^'s Power> moi1gh imperfectly understood, seemed sufficient crystalliza- to disturb a process so variaWt* and delicate as that of crys- tionof water tallization : which we know is affected by the speedy or slow into ice j — . j r j abstraction of heat or of moisture, the presence or absence of light, the action of tremors of any kind, and several other rallvat" e^ne accidents j~ and from a supposed difference in the agency of plain the pre- such a power upon the water immediately over the drowned sen ac b. man, and upon the other water, there appeared good grounds to account in a general way for the difference in their respective qualities. More particu- My own reflections, since I had the pleasure of this conver- ter invtst»ga- satjon> wi)i afforcj a few additional remarks, which may give a more specific form to this explanation. I am disposed to think that the effect was caused by the developement of heat in The body the body, occasioned by the putrefaction or chemical change must have which must have taken place, though it may have proceeded been slightly , - . , , - . . , heated by its very slowly, on account of the coldness of the water, and the chemical want of communication with the external air. This would andTwo'uld occasion a small degree of expansion in the water, in contact ■warm the wa- with the body, and cause that fluid to.ascend perpendicularly to which^voulV tne sur^ace 5 where it would spread itself (thinly) on all sides, ascend, &c. and when cooled would descend near the circumference, as is outline of the da'^' seen wit^ ^ui^s neated f,om beneath. Or, in other words, figure. the particular mass of water, in this stagnant pond, which was perpendicularly over the corpse, and consequently had the same precise outline, as to all its horizontal sections, would be a little, warmer than the rest. And though this circulation would be a little modified by the expansion to which water is subject, when cooled below 40°, yet this would scarcely in any case affect the result, and not at all, if the freezing came on suddenly. It appears from our meteorological tables that it did so, on the 1 1th December. The water ex- Now these simple facts might, and probably did, occasion the tenor to the great differences in the ice. For the external water, being freeze first originally colder at the commencement of the frost, would confusedly, 80oner be cooled down to the freezing point, and begin to con- and form , . ,.,,, • , ©pake foul geal over its whole surface, while the other part would remain kft fluid. HOT FOUNTAINS OF THE AZORES. 305 fluid. The congelation being sudden, and from all points at once, would be of that kind which chemists call confused crys- tallization j forming an opake mass, and including the impuri- ties of the liquid in its substance. But the water over the body The water . , . , , .j A over the body being warmer, would not congeal at so early a period, except won](j frt,e«. with regard to a few spiculae, which would shoot into it from more slowly, the surrounding ice, and form the white border of the figure j wjlite i>ortier and when at last its surface became gradually cooled down to the to the outline, freezing point, this water would freeze, not all at once, but by a jJanMce1" slow crystallization, from the edge inwards ; which is the very within, process for making clear ice, used by Achaed, id his electrical ex- periments, and is known to exclude all air bubbles, and mecha- nical mixtures of impurity from the crystals. These effects, indeed, suppose a concurrence of favourable The effects Te- circumstances which may rarely take place, but really appear . ® **© K ■iiiiii'!i!!iiiiF!!ii:i!^riiii!iiiiniiiitiiiiaiwiiiii:iii ^iimimiiil-^ j£" JOURNAJL . OP NATURAL PHILOSOPHY, CHEMISTRY, AND THE ARTS. SUPPLEMENT TO VOL. XXXIV. ARTICLE I. An explanatory Statement of the Notions or Principles upon which the systematic Arrangement is founded, which was adopted as the Basis of an Essay on Chemical Nomenclature. By Professor J. Bprzelius. (Continued from p. 246.) IF we admit that 100 p. of antimony form the white oxide The proper- with 27*8 p. of oxigen, and the sulphuret with rather more 1?°° and of'" than 37 p. of sulphur, this result corresponds very well with sulphur in an- these data, and proves that the white oxide contains ]| times tlm* c,om~ ^ r 2 pounds are the as much oxigen as the fusible oxide, and that the sulphur in same as with the sulphuret is to the oxigen in the fusible oxide in the same olaeT metals* proportion as we have found with the other metals. For if, in this case, the white oxide be composed of 7825 p. of metal, and 21*75 of oxigen, this last, in the experiment I have men- tioned, was replaced by 29 p. of sulphur — that is to say, 7*25 p. more than the weight of the oxigen 5 and these 7 25 p. making precisely one-third more than the weight of the oxigen,, and the antimony is to the sulphur, in this experiment, as 100 : 3707. If any one among the experiments had produced a very de- cided result, we might easily have calculated the others from it; Supplement.— Vol. XXXIV.— No. 100. Y but 314 METALLIC OXIDES. but at present we must be content with the mean or average numbers. ... \ \ How ox- 5* Yettnw oxide of antimony. If antimony be digested kkof anti- with the nitro-muriatic acid, or with fuming nitrous acid, and tinK^di^ested tne solution be evaporated to dryness, and then sufficiently with nitro- heated to drive off the acids without igniting the mass, ftimin^nitrmis a ve^ow P°wder is obtained, which is often crystalline, and, acid, the dried if strongly heated in the fiflfc becomes white, and consequently massisjeiiow. d|d not owe its (yeijow) colour to an adulteration with the red oxide of iron. 100 p, of me- When I made this experiment in a glass phial, weighed, and oxideVt 13° maa*e use °* me fuming nitrous acid, I obtained as much as 131 p. of a yellow crystalline powder ; but when I had oxiu-cd the metal by means of the nitro-muriatic acid, the result did not exceed 129 or 130 p. of oxide from 100 p. of metal, and new cohobations of acid upon the yellow oxide did not increase the weight. The addition of 30 or 31 p. of oxigen does not agree with any proportion of those which I had before found, supposed to and * began to suspect a combination of two ditferent degrees be n com- of oxidation had been formed, and that this combination could SXenfdetW° not be farther oxlded bY meanS of acids' grees ofoxida- I shall not mention the various unsuccessful experiments I lW)n, made to clear up this intricate subject, but shall speak only of those which afforded more satisfactory results. Antim. oxided \ mixed powdered antimony with the red oxide of mercury. ©? mercury6 PrePared fr°m vei7 Pure mercury, and heated the mixture in a glass retort. At a certain temperature it took fire, and the mass became red. I continued the heat as long as any mercury was condensed in the neck of the retort j after which, at length, there remained a deep olive-coloured powder. I heated coloured pow- tms w,tn Sreat care in ag*ass capsule, by which treatment it lost tier. its olive colour, and left a straw-coloured powder in the capsule. -The yellow One hundred parts of this powder very strongly heated in a oxide loses platinacrucible,left, in different experiments, from 33 5 to 3375 one fourth of r , .. ..... rT , , * , its oxi«en by parts of white oxide of antimony. In order to determine the heat, and be- nature of what had been dissipated by the heat, the experiment eomes white ... ,, . , , . . oxide. Wltn tne ye"Ow oxide was repeated in a small glass retort, with a small apparatus for collecting the gas. When the re- tort began to be strongly ignit/id, a gas was developed, and when this ceaied tBe retort was removed from the fire. The residue METALLIC OXIDES* S15 residue was white oxide, and the ga0 verf pure oxigen. These experiments prove, that the yellow oxide is decomposed by the heat by losing part of its oxigen j and as 03'75 p. of white oxide contain 20 24 of oxigen, it is clear, that the yellow oxide loses, on this occasion, one-fourth of its oxigen, and that it contains if as much oxigen as the white oxide, and twice as much as the fusible oxide (oxidum stibiosum.) There are several other metlfbds of producing the yellow Other me- oxide (a.) If into a long-necked tubulated phial a certain *."ods of P™' ° r ducmg yellow quantity of metallic antimony be put, and heat be applied to a oxide (a) by cherry redness, and continued four or five hours, the antimony mere heat; gradually combines with oxigen -f a small quantity of white oxide sublimes into the neck of the glass, another portion es- capes out of the aperture ; but the greatest part of the oxided metal forms a yellow crust round the border of the fused me- tal. In this form the yellow oxide is not crystallized j it has much tenacity, and is difficult to break. (b) If one part of antimony in powder be burned with (b) by com* 6 p. of nitre in a red hot crucible, the burned mass is then J!™.^011 Wltl1 decomposed with nitric acid, which leaves a white powder not dissolved. This powder is a combination of the yellow oxide with water, which may be driven off by heat over a spirit lamp. The oxide is then left of a very clear and fine yellow colour. The degrees of oxidation of antimony may therefore be Degrees of expressed by the series 1, l£, 2 : but we have not compre- oxlda,t!on . ,,,,,,...,.. ,. . . , t statedinsenei bended the suboxide in this series, which contains less oxigen. l,— ,4, 6, 8. than the first of the series. If, from what I have endeavoured to make probable with regard to sulphur and arsenic, the quan- tity of oxigen in the suboxide be one-sixth of that in the white oxide, or one-fourth of the fusible oxide, the series will be I, — ,4,6,8. If, on the contrary, future experiments should prove, that the oxigen in the suboxide is only, in fact, half that of the fusible oxide, the series will become 1, 2, 3, 4. Although it is very clear, that the middle numbers must be deficient in precision, particularly when, at the same time, they are not founded upon good experiment, yet we must, amidst results so little fixed, content ourselves with an approxi- mation of this nature. And by assuming, that the oxidum stibiosum is composed of 100 parts of metal, and 18*6 p. of Y ,2 oxigen ; 316 METALLIC OXIDE?. oxigen j and that the suboxide contains with 100 parts of metal one-fourth part as much, the oxides of antimony will be com- posed as under, Met. Oxifcen. Metal. Oxi?en. Metal. Ox. Table of the The suboxide 100 465 96-326 3174 215065 100 proportions otThefasibleo oxigen in the 100 I860 84317 15-683 53763 100 four oxides of The white ox. 100 27*90 78- 19 21810 35841 100 antimony. The yellow ox. 100 3720" 72'85 27- 150 268 81 100 Yellow oxide Now, if we calculate the composition of the yellow oxide by n. acid ap- obtained by the action of nitric acid upon antimony, we shall pears to be . . ' r . composed of find it such as it would be if composed of the white oxide and (fee white and the yellow oxide, in such proportions as that each of them vellovv oxides, ... . . .,-.«. in portions should contain an equal quantity of oxtgen*. containing equal qoanti- [The following annotation, 07 account of its length, is continued ties of oxigen. ^ ^ ^ of ^e M^ Other in- * In proportion as our researches shall be extended, we compounds of sna^ mic* aDnndance °f *"cts °f tms nature. In my first essay two oxides, upon determinate proportions, I had the notion, that the dif- each of which ference 0f coi0ur in precipitates, caused by the alkalis in the appears to \ i > J eontain the solutions of iron depended on a combination of two degrees of same quantity oxidation of iron, which probably afforded salts with excess of or oxisren ; and , , serve as the base, and I gave examples in the nomenclature by the prussias bases of com ferroso-ferricus, sulfas ferroso-ferricus, &c. One circumstance, pound salts. . . , ., . , ■ . . .. , . . . t which strikingly proves these notions, rs found in the phosphas ferrosus. By precipitating sulphas ferrosus by means of a neutral phosphate, a white precipitate is obtained j and the same happens by precipitating the phosphas ferricus. But the first, the phosphas ferrosus, acquires a fine blue colour by the washing, which does not happen with the latter. In fact, a blue precipitate is obtained by the alkaline phosphates, in a mixture of the sulphas ferrosus and sulphas ferricus. The blue phosphate of iron is, therefore, a salt with double basis, containing the two oxides of iron, representing two different bases, and it constitutes a phosphas ferroso ferricus. The phos- phas ferrosus, on the contrary, is whhe, as well as the phosphas Metals pos- ferricus. I have reasons to think, that several metals, viz. sess this habitude. manganese, uranium, cerium, and mercury, have the property of producing salts with double bases, by combining their two degrees of oxidation. But it is, no doubt, still more interest- ing METALLIC OXIDES. 317 ing to find that the same kind of combinations likewise exists between the different degrees of oxidification of the same radical. It is known, that M. Gay Lussac, by extremely in- The same doc* teresting researches, has found that 100 p. in volume of azote Jn"e aPphed w - r to the bases gas combine with 50 p. in volume of oxigen gas, to form the of acids; e. g. nitrous oxide, — thai with 100 p. of oxigen they form nitrous az?re and gas, and with 200 p. nitric acid. The series would here be 1,2, 31, 4, which is contrary to all analogy with other bo- dies. The irregularity of this series did not escape the attention of this learned chemist ; but he endeavoured to remedy it by considering nitrous acid as composed of three volumes of nitrous gas, and one volume of oxigen gas. The analogy with the other oxides combined with the results of sny experiments on the nitrites is here, in fact, 1, 2, 3, 4 $ and that the nitrous oxide, such as it is found in the nitrites, is composed of 100 p. in volume of azote, and 150 p. in volume of oxigen. But if we consider that, probably, neither the nitrous nor the nitric acid are capable of existing together in insulated states, as is also the case with many other acids j and that when nitrous acid is produced, the result would be a combination of the nitrous with the nitric acid as oxided bodies, and in such pro* portion that each shall contain an equal quantity of oxigen, the quantity of oxigen absorbed will be precisely what was found by M. Gay Lussac. (Here the annotation ends ) A very interesting question remains to be considered respect- The yellow- ing the oxides of antimony. What is their chemical nature ? and the bine tim .. .. ... ^ oxides ot an- ls the yellow oxide a superoxide, or has it the properties of an timony have acid? The following experiments will prove, that the yellow the .character* oxide, as well as the blue, possess the characters of acid;, and that the yellow oxide may be considered as an acidum stibicum> and the blue as an acidum stibiosum. (a) Combinations of the acidum stilicum with saline bases, stibiates. I burned 10 grammes of antimony in powder, with 60 Combination* grammes of pure nitre in a silver crucible, and the mass was °* ac- stibi* , , , . . , ,. , , . cum (or yellow heated during an hour in the highest temperature the vessel oxide) with could support. I pulverized the white mass which was thus »aMn« bases. obtained, washed it with cold water as long as any nitrate of gtibiateof potash potash. 31 S METALLIC OXIDES. potash could be so dissolved ; a white powder was then left, which I dried upon blotting paper. One part of this powder boiled for some hours with water was dissolved, and I passed the solution through the filter. The filtered liquid had a slightly bitter taste, rather metallic. It restored the blue of turnsole paper, which had been reddened by a weak acid, and the smallest quantity of a diluted acid caused a precipitate which was notredissolved in the fluid. The precipitate afford- ed by the acetic acid, well washed, was white and tasteless ; but it reddened turnsole paper, although the filtered solution had not yet lost the property of acting like a weak solution of alkali. The while precipitate caused by passing a current of carbonic acid gas through the alkaline liquor, had the same property of reddening turnsole paper j a property which con- sequently belongs to the precipitated oxide, and cannot be owing to the combination with the acid, which served to pre- cipitate it. The dry precipitate did not, in several months, lose the property of re-acting like an acid upon vegetable co- lours. But when I heated it in a retort over the flame of a spirit lamp, a quantity of water was disengaged, which did not red- den them, and was very pure j and the yellow oxide which remained had lost the property of reddening turnsole paper, deprived of its One part of the saline solution, evaporated in a silver cru- anhydrhTsti- c»We, left a white mass. 1 decomposed this by digesting it fciate. with diluted nitric acid, by successive operations, to extract the potash. The undissolved oxide was white. I washed it with much water, and at las|j dried it at the temperature of boiling water j and then I heated certain portions, previously weighed, in order first to drive off the remaining water, and next the oxigen, until the white oxide only should remain. Jn several experiments 100 parts left 88'3, 887 and 88'9 p. of white oxide. The quantity of oxigen combined with 88'7 p. of the white oxide, in order to form the yellow oxide, is, from what we have determined, 6 45 j and therefore the quantity of water was only 4°78. But 959,2 p. of yellow oxide contain 2581 p. of bxigen, and 4'78 of water contain 4"218 ; now, 4*218 x 6=25*3 It follows, therefore, that t,he white powder not dissolved by the nitric acid, is an hydrique stibiate, that is to say, a combination of stibic oxide, with water, as its base, and jn which the acid contains six times as much oxigen as water. The &c. The nitric acid by which the stibic acid was separated from the Valine mass, contains nitrate of potash. This saline mass was, therefore, in fact, a stibiate of potash. (To be continued.) II. Inquiries relative to the Structure of Wood, the specific Gravity of its solid Parts, and the Quantity of Liquids and elastic Fluids contained in it under various Circumstances ; the Quantity of Charcoal to be obtainedfrom it -} and the Quan- tity of heat produced by its Combustion. By Count Rum- Ford F. R. S. Foreign Associate of the Imperial Institute of France, &c* SINCE the days of Grew and Malpighi, there have been but few regular inquiries into the structure of wood. The science of botany has, indeed, taken an excursive range j and the indefatigable zeal of modern naturalists, who have travelled over all the known world, has made us acquainted with an astonishing number of plants, unknown before in Europe, and therefore called neiu , by which our gardens and apartments are embellished with a profusion of gay flowers j but still the know- ledge of the vegetable economy >s scarcely at all advanced. The circulation of the sap in plants is still a subject of dispute, and the causes of its ascension are very imperfectly known. The specific gravity of the solid parts which form the wood of plants, is unascertained, and, by consequence, the proportions of solids, of liquids, and of elastic fluids ; the component parts of a plant, with the variations to. which they are subject in different seasons, are matters of which we are still ignorant. Jt is, indeed, known, that the wood of a tree remains and preserves its primitive form after it has been converted into charcoal j but no one has explained this extraordinary pheno- menon, very little attention having been paid to it. An earthen vessel becomes hard and brittle in the potter's furnace ; the vessel shrinks during the operation of baking, * Read at the sittings of the first class of the Institute, September 28, andOetober 5, lbie. but 3 20 STRUCTURE OP WOOD, &C* but it undergoes no alteration of shape. This phenomenon is easily accounted for : the water which distended the particles of the clay, kept them at a distance from each other, and ren- dered the mass soft and flexible, having been expelled by the power of the heat, the several particles contract themselves together, and form a hard and brittle body, though the clay remains the same before and after the operation. Is it not possible that wo^d is converted into charcoal by a similar process ? For, either the charcoal is already formed in the wood, or the wood being decomposed, the charcoal is formed of its elements, or a part of them. But is it not evi- dently impossible that the elements of a solid body should be so totally deranged as to separate tl em entirely from each other without destroying the form or figure of the body ? In the sequel of this paper it will be shewn, that the specific gravity of the solid parts of any kind of- wood is very nearly the same as that of the charcoal obtained from it, a circum- stance that gives a great degree of probability to the hypothe- sis, that the two substances are identically the same. But I do not mean to amuse the Class with a detail of my own conjectures ; it is to my experiments and their results that I now claim the honour of calling its attention. I was by accident first induced to enter upon this examina- tion and inquiry into the structure of wood. In the course of a long series of researches upon heat, I wished to determine the quantities of that element produced by the combustion of different kinds of wood j but I had scarcely began the inquiry when I found, that in order to procure satisfactory results to my experiments, it was indispeusably necessary to obtain a better knowledge of wood itself j and, therefore, I imme- diately devoted myself to the study. My first aim was to determine the specific gravity of the solid parts which compose the fabric of the wood, in order afterwards to determine the quantities of sap or water contained in wood under various circumstances. Having found, that very thin shavings filled with sap, or even with water, could be thoroughly dried in less than an hour, without injury to the wood, in a stove kept at a higher temperature than that of boiling water, or at about 50° of STRUCTURE OF WOOD, &C. 321 of Fahrenheit's scale, (= 200° French) I determined on using shavings of this description in my experiments. Section!. Of the specific Gravity of the solid Parts of Wood, I began with the wood of the lime-tree, of which the tex- Specific gra* ture is very fine and regular. From a small board, five inches v,,v ot f,le i i . ,r . , . . , , t • - parts ot wood, Jong and half an inch thick, very dry, I took a quantity of &c. thin shavings with a very sharp plane. These were exposed for eight days in the month of January, upon a table in a large room, not otherwise occupied, in order that they might attract from the atmosphere all that moisture which, as an hygrometric body, they were capable of imbibing. The temperature of the room was about 46 F. Ten grammes (154'5 grs.) of those shavings, laid on a China plate, were placed in a large stove made of sheet-Lon, and there exposed to a regular heat of about 245° F. for two hours, in the course of which time they were frequently taken out and weighed, in order to observe the progress ot their drssica- tion. When they ceased to lose weight, the operation was stopped j when perfectly dried, their weight was 8*121 grammes. By previous trials with my apparatus, I had learned, that if the stove was too much heated, the shavings became disco- loured, which is always indicated by the emission of a particu- lar odour, very readily to be perceived ; but, by a careful regu- lation of the fire, this accident may be avoided, and the shav- ings be thoroughly dried without injury, or even subjecting them to any sensible alteration. I concluded that they had not undergone any change, be- cause, upon again exposing them to the atmosphere, they re- gained the same weight which they had, under similar circum- stances, prior to their being dried in the stove. Being thus possessed of the weight of my shaving?, as well under exposure to the air as in a dried state, which 1 uter I could not but look upon as being perfect, it only remained to ascertain their weight in water when all their vessels at^d pores were completely filled with that liquid, to enable me to deter- mine 322 STRUCTURE OF WOOD, &C. Specific gr.i- ;nine the specific gravity of the solid parts of this wood, which pities ot wo jd, was accompi|shed without difficulty by the following process: A cylinder copper vessel, ten inches in diameter, and as many deep, was filled with water from the Seine, previously well filtered, and being set upon a common chafing dish, was made to boil for some time, to expel the air contained in the water. The shavings were then thrown into the boiling water, and kept in that state for an hour. The water was not long in filling the vessels and pores of the shavings, from which it dislodged the air contained in them ; so that the wood, speci- fically heavier than the water, was precipitated to the bottom of the vessel, and there remained. When the vessel was removed from the chafing-dish, the water was suffered to cool to the temperature of 60° F. and then plunging in both hands, I placed (under the water) all the shavings in a cylindric glass vase, whose weight I had previ- ously ascertained, which was suspended in the water by a silken cord, fastened at its other extremity to the arm of an accurate hydrostatic balance. On weighing the shavings in the glass vase thus immersed, I found their weight equal to 2*651 grammes. As the shavings, while dry, weighed 8*121 grammes, in the air, and 2*651 grammes in the water, they must have lost 5*47 grammes of their weight in the latter j consequently, they must have displaced 5*47 grammes of water ; and the specific gravity of the solid parts of this wood must be to that of the water, at the temperature of 6CT F. as 8*121 to 547, or as 14*846* to J 0*000. It may, perhaps, excite some surprise, that the solid parts of so light a wood as that of the lime-tree should be heavier, by nearly one-half, than water, taken in equal bulks. But this surprise will, without doubt, be increased when I declare, that the specific gravities of the solid parts of all kinds of wood are so nearly alike, as almost to induce a belief, that there is the same identity in the ligneous substance of all sorts of wood, as in the osseous substance of all species of animals. I procured, from a joiner's work-shop, dried wood of the eight following species, viz. poplar, lime, birch, fir, maple, beech, elm, and oak ; and had them cut into small boards, five inches in length, and six inches broad, from each of which ( I STRUCTURE OF WOOD, &C. S23 I planed off some thin shavings, and exposed them to the air Specific gra- for eight days, in the month of January, in a large room, vitie* ofwood, where the temperature, which varied but littje, was about 40° to 45° F. When these shavings had acquired their ordinary degree of dryness under existing circumstances, ten grammes of each * sort were weighed off, and. being hid separately in China plates, were thoroughly d/ied in the stove. On being taken out of the stove, they were again weighed, and then thrown into boiling waier, to expel the air from their pores, and to moisten them thoroughly. Wh«n they had boiled for an hour, they were suffered to remain in the liquor till it was sufficiently cool ; and after they had been weighed in the water, the specific gravity of their solids was calculated in the usual way. The following table gives the details and results of this in- quiry. Weight. Species ofwood. Exposed to the air in a room in winter. Tho- roughly dried in a stove. In the water at 60° F. grammes Specific gra- vity of ihe solid parts ot the wood. Weight, of h :ubic inch of the solid jarts of/ the wood. grammes grammes Poplar 10 8045 2-629 14854 2945 Lime 10 8121 2-651 14846 2940 Birch 10 8062 2*632 14848 2944 Fir 10 8247 2-601 14621 28-96 Maple 10 8- 137 2563 14599 2893 Beech 10 8 144 2*832 15284 3030 Elm 10 8- 180 2793 15186 30- 11 Oak 10 1 8*336 2905 15344 3042 W ater 10000 19*83 The specific weight of the solid matter which composes the fabric of these woods is so nearly alike in them all, that the small variations to be observed in the different experiments, may, perhaps, be accounted for otherwise than by supposing the ligneous substance to be essentially different in the several species. The charcoal obtained from the various kinds of wood, if carefully prepared, has no sensible difference ; and all the seer-woodi 324 STRUCTURE OF WOOD, &C. seer-woods give nearly the same chemical results when treated in the same manner. Hence, without doubt, we have good reason to suspect, that the ligneous substance of all woods is identical. But without stopping to discuss this question at pre- sent, I shall endeavour to elucidate another, no less interesting, and which yields results more satisfactory. Section II. Of the Quantities of Sap and Air discovered in Trees, and in Seer-zvoods. Sap, &c. in Greeve and Malpighi discovered in plants certain vessels, woods" which they suspected to be destined for the reception of air ; and many physiologists have supposed, that the air found shut up in the vessels of plants, which (if it be really confined there) would necessarily cause a reaction upon the neighbour- ing vessels, with an elastic force, as variable as the temperature to which this elastic fluid is exposed, and might probably con- tribute to the circulation of the sap. It would, doubtless, be an interesting question to determine precisely the quantity of air contained in plants in different seasons, and under various circumstances. By examining the variations to which this quantity of air is subjected, and com- bining them with other simultaneous phenomena, we might hope to make some discovery which may assist us a little to elucidate the profound obscurity that at present conceals this part of the vegetable economy. The specific gravity of the solid parts of a plant being known, it becomes very easy to determine, in every case, the quantity of air contained in its vessels and pores. Thefollowing example will render this position perfectly clear : An oak, in complete health, in a growing sta*e, was cut down on the 6th of September, 1812. A cylindrical piece, six inches long, and rather more than an inch in diameter, taken from the middle of the trunk of this young tree, three feet above the earth, weighed, when full of sap, 18T57 grammes. Upon plunging this piece of wood into a cylindric vessel about \\ inch in diameter, and Q\ inches in height, filled with water at the temperature of 62° F. it displaced 188*57 grammes of the STRUCTURE OF WOOD, &C. 325 the wafer* j whence" I conclude with certainty that this piece of Sap &c in oak, filled with sap, possessed a bulk equal to Q50g3 cubic different kind* inches, that its specific gravity was 965 15, and, consequently, wood* that a cubic inch of it weighed 19- 134 grammes. When the piece of wood had been reduced to the shape of a small board, about half an inch in thickness, I took from it forty very thin shavings weighing 199 grammes, but when thoroughly dried in the stove, at a temperature of 262° F. they weighed only 1245 grammes. From this experiment, it is evident that the wood in ques- tion, being full of sap, was composed of 12'45 ligneous parts* and 7*45 parts of water, or of sap, whose specific gravity is nearly the same as that of water. Now, as one cubic inch of this wood weighed 191 34 gram- mes, it is very certain that it was composed of 1 l'Q^l grammes of ligneous parts, which were, consequently, solids, and of 7* 163 grammes of sap. But we have already seen, from the results of the experi- ments detailed in the former part of this memoir f, that a cubic inch of the solid parts of the wood of the oak, weighs 3042 grammes } consequently, the 11*971 grammes of solid parts * In order to determine and keep an account of the quantity of water remaining on the surface of this piece of wood at the instant ot" withdrawing it from the vessel, it was weighed when taken out, whilst still quite wet. As its weight had been taken previously to the operation, the augmentation it had acquired from the water was as- certained to a nicety. The vessel when empty weighed 188*22 grammes, and when filled with water at the temperature of 60 F. 474'9- grammes ; so that it contained 286*68 grammes of water. When the piece of wood was plunged into the water, a small glass plate, about two inches in diameter, and two lines in thickness, ground with emery, to fit it to the edges of the vessel, so as to close it hermetically, was laid upon its mouth to shut up the piece of wood with the water still remaining in the vessel, whilst its outside was wiped with a dry cloth. When the exterior of the vessel had been thoroughly dried, the glass cover was carefully removed, and the piece of wood withdrawn ; the vessel was then weighed again with its remaining contents of water ; and from its weight the quantity of water displaced by the wood, wa* calculated. t See the table, page 5?3. found S{26 STRUCTURE OP WOOD, &C. Sap, &c. in found in one cubic inch of this wood, when the tree was alive.j of wood. J could have no greater bulk than 0*39353 cubic inch. As one cubic inch of water weighs 10/83 grammes, the 7'i63 grammes of sap, found in the cubic inch of this wood, must have occupied a bulk equal to 036122 Consequently, a cubic inch of the wood in question, contained a quantity of air, whose bulk was equal to 0' 24525 Making together 1*00000 cubic inch. We Conclude from these results, that a young oak, in a grow- ing state, at the beginning of September, when the wood appears to be diffused with sap, contains, nevertheless, about a fourth of its bulk of air, and that its solid ligneous parts do not make quite 4-10ths of its bulk. But we shall presently see that the lighter woods contain still less of ligneous parts, and more of air, than the oak. A young Italian poplar, three Inches in diameter, measured at two feet above the earth, was cut down on the 6th of Sep- tember, whilst the tree appeared to be in a growing state. The specific gravity of a piece taken from the middle of the trunk, was found to be 5/*946 j consequently, a cubic inch of this wood weighed 11 '49 grammes. From a piece of this wood, apparently fuJl of sap, 40 thin shavings were taken, six inches in length, and half an inch broad. The wood from which these shavings were planed, weighed 12*37 grammes, and the shavings, when thoroughly dried in the stove, weighed / 5 grammes*. • As the heat excited by the plane in taking off these shavings, was sufficient to evaporate a very sensible quantity of sap belonging to the wood from which they were cut, the shavings became percep- tibly dry during the operation ; for I found that 40 thin shavings sometimes lost more than one gramme (about l-12th of their weight} in less than a minute. In order to obtain their true weight, whilst they still remained patt of the wood, I adopted the precaution of weighing the piece of wood, both the moment before, and the moment after the operation of planing. The difference in the weight of the wood, under these two circumstances, indicates the weight necessary to be given to the shavings, and which is here always attributed to them. We STRUCTURE OF WOOD, &C. 3%7 We hence conclude, that a cubic inch of this wood, in its Sap, &c. ia original state, while the tree was still alive, contained 7*1531 different kind* ot wood, grammes of ligneous parts, which formed the fabric of the wood, and 4'33f3o, grammes of sap, differing in its specific gra- vity, little or nothing from common water. As one cubic inch of the solid parts of this kind of wood weighs 29*45 grammes*, the 7*1531 grammes of ligneous parts found in a cubic inch of the trunk of the living tree, in Sep- tember, could only have occupied the space of 0*24289 cubic inch. And the 4*3369 grammes of sap, contained in it, only 0*21 890 Consequently, in one cubic inch of this wood, there was a bulk of air equal to. . O 53831 Total, . . . . ? 1*00000 cubic inch. The difference between the structure of the oak and of the poplar, becomes very conspicuous on making a comparison, according to the subjoined method, between the constituent parts of these two kinds of wood, both in a growing state. Thus, a cubic inch of wood is composed of, Ligneous parts. Sap. Air. The oak 039353 0*36122 024525 The poplar 024289 0*21880 0-53831 This striking difference, in the proportions of the ligneous substance of sap and of air, discovered in these two species, sufficiently explain the difference observable in their weight and hardness. This inquiry may probably lead to other dis- coveries of more general utility in the study of the vegetable economy. Section III. Of the relative quantities of Sap and Air found in the same Tree, in [Pinter and in Summer ; and in different portions of the same Tree, at the same time. The following experiments were undertaken with a view to * See the table, page 323. discover JOg STRUCTURE OP WOOD, &C. discover the difference between the quantities of sap and air wood at diffe- ^ouncl in tne wood composing the trunk of a large tree, in rent seasons, winter and in summer. On the 20ih of January, 1812, I had a lime-tree felled, of about 25 or 30 years growth, which had stood among several others of the same age in my garden at Anteuil. On taking a piece of wood from the middle of the trunk, at about three feet above the ground, it appeared to be filled, and even drowned in sap. Its specific gravity was 76Q\7 > consequently, one cubic inch of the wood weighed 15"788 grammes. Having planed off 10 grammes of thin shavings from this piece, and dried them thoroughly in the stove, I found their weight reduced to 472 grammes. Thus in possession of the specific gravity of the solid part of this wood, it was easy to determine, with the aid of these data, the constituent parts of a cubic inch, which were as follow : Ligneous parts 0*25353 cubic inch. Sap 044549 Air 0 30098 1 00000 On the 8th of September, in the same year, (1812) I had a piece of wood (=5*84 cubic inches) cut from the trunk of ano- ther lime, of equal age with the former, (from 25 to 30 years) at the height of three feet above the earth. This tree was in a growing state, ?nd the piece taken from it, after it had been trimmed by the joiner, weighed 87'8 grammes, and displaced 1158 grammes of water, at the temperature of 62° F. conse- quently, its specific gravity was 75820. In the month of January, the specific gravity of this same species of wood had been found to be 796 17- From the piece of wood taken from the tree on the 8th of September, I had 14"19 grammes of their shavings planed off, which, after they bad been thoroughly dried in the stove, weighed only 7 35 grammes. Hence we have, as the consti- tuent parts of a cubic inch of this wood — Ligneous STRUCTURE OF WOOD, &C. 32$ Ligneous parts 0*26489 cubic inch. Sap, &e. in Sap 036546 wood' Air V.V . . 0'36965 1 -ooooo From the results of these two experiments, we may con- clude, that the body of a tree contains more sap in the winter than in summer, and more air in summer than in winter. But the following experiments demonstrate the snp to be very disproportionately distributed in the several parts of the same tree, at the same season. On the 8th of September, I had a branch, about three inches in diameter, cut from the lime just spoken of, and which issued from the trunk at the height of ten feet above the surface of the earth. From the lower end of this branch, I took a piece of wood, and subjected it to the investigation requisite to ascer- tain its constituent parts. Its specific gravity was 70201. The same day, T found the specific gravity of a piece of the trunk of the same tree, to be 75820. Surprising as this difference appeared, my astonishment was still more excited, on finding that a piece of wood, of three years growth, cut from the upper end of the same branch, where it was but one inch in diameter, had a specific gravity of 85240. There was, therefore, much more sap, and less air, in the wood of the upper extremity of the branch, than in the lower, which was nearer to the body of the tree. I afterwards examined the young shoots of the current year, in the same tree, as well as in several other species of wood, and uniformly found that the specific gravity of the young wood, that is to say, of the current year, is always considerably greater than that of the same species of wood when grown older. Doubtlessly, because it contains more sap, and less air, than the old wood. In the management of experiments for determining the spe- cific gravity of wood of the current year, it is indispensably necessary to take an account of the space occupied by the pith, without which precaution, we shall be led to false conclusions. Supplement.— Vol. XXXIV.— No. 160. Z I found 330 STRUCTURE OF WOOD, 6CC. Sap and vola I found the specific gravity of the oak of the current year to llooda,t' ^ be u6530> that of the e]m> H0540. Young shoots of these trees, deprived of their bark and pith, descend rapidly on being thrown into water j whilst pieces of the same tree, moie advanced in age, swim on the surface, even when the wood is green, and more full of sap. This fact is worthy the attention of persons occupied in the study of vegetable physiology. I was next curious to examine the root of the lime from which I had already had one piece of wood from the trunk, and two pieces from one of its branches. With this view, on the 8th of September, 1812, I caused one of its roots, of about two inches diameter, to be tnken up, and cut from it a piece weighing 9325 grammes, which displaced 1 15'8 grammes of water. Its specific gravity was 80527, and, consequently, greater than that of the wood extracted from the trunk of the same tree, but less than that cut from the upper end of one of its branches. 20 48 grammes of thin shavings, from this piece of the root of the lime, weighed only 10*85 grammes after being thoroughly dried in the stove. From these data, I determined the constituent parts of a -cubic inch of the root, thus : Ligneous parts 0*28775 cubic inch. Sap 037358 Air O 3386*7 1*00000 The constituent parts of a cubic inch of the body of the same tree, were, as we have shewn : Ligneous parts 0*26480 cubic inch. Sap ". 0.36*546 Air „ 0*36965 1 00000 The constituent parts of a cubic inch of the wood of the same tree, taken the same day from the lower extremity of a branch, were : Ligneons STRUCTURE OF WOOD, &C. 331 Ligneous parts 0-25713 cubic inch. Sapand vola- Sap O 27513 ™"c Parts m 1 ' wood. Air 0 46774 rcoooo Lastly, the constituent parts of a cubic inch of the wood, taken near the upper extremity of the same branch, were : Ligneous parts < 0253 88 cubic inch. Sap 0-47599 Air 0-27013 1 -ooooo For the more easy comparison of the results of these four experiments upon the wood of the lime tree, made on the same day, with different portions of the same tree, I have collected them together in the following TABLE. The root The trunk The lower end of a branch... The upper end of ditto. . , . Wood taken from the trunk of a lime tree of the same age, on the 20th of Jan. . } A cubic inch of wood was composed of Ligneous parts. Sap. Air. 0-28775 0-37358 0-33867 026489 0'36546 0-36956* 0*25713 0-27513 0-46774 0*25388 0-47599 027013 025353 0*44549 0-30098 Being desirous to ascertain whether a difference considerable enough to be valued, existed between the wood of the heart, or core, and the sap wood found between the rhind and the body of the same tree « I took on the nth of September, an elm faggot, five inches in diameter, lopped from a large tree, which had been felled on the 20th of the preceding April, and bad two cylindrical pieces, each six inches in length, cut out of it. The thickest of these taken from the core, weighed 191 '05 grammes, and displaced 194*45 grammes of water $ the other, Z *2 consisting 332 STRUCTURE OF WOOD, &C. Sap and vola- consisting of the sap-wood, weighed 93*61 grammes, and dis- ttte parts in p|ace(j 1 iV45 grammes of water. The specific gravity of the core was, therefore, 08251 ; that of the sap-wood, 817*64. But as the faggot had lain exposed to all the summer rains, the wood was far from being dry. I was, however, much surprised at discovering, that the core of this wood was more charged with sap, or water, than that of the same kind of wood when in a growing state. A fact which induces a suspicion, that the sap in trees is not enclosed in,ves- sels or tubes apparently impervious to that liquid. To obtain a better knowledge of the wood in question, I planed off 40 shavings, six inches in length, and hdlf an inch in breadth, from a small board cut from the core ; with an equal number of shavings, of similar dimensions, from another board cut from the sap-wood. The 40 shavings from the core, taken just as they were planed off, weighed 16*37 grammes, and 1053 grammes after they had been thoroughly dried in the stove. The 40 shavings of sap-wood weighed 1697 grammes before they were dried, and 1 1*99 grammes afterwards. Thus possessed of the specific gravity of the solid parts of this kind of wood, it only remained to determine, from these data, the constituent parts of an inch of the wood, which was readily performed, as follows : Ligneous parts. Sap. Air. In the core of the elm. . 0*41622 I 035055 I 0*23223 In the sap. wood 0*38934 | 0*23094 | 037072 It appears, from the results of these experiments, that the sap-wood of the elm contains rather more ligneous parts in its timber, than the core of the same tree j and that it contains much less sap, and more air. But as the tree had been felled nearly five months before it became the subject of investigation, it is very possible that the sap wood had become much drier than the core of the tree. 1 had purposed to repeat these experiments upon wood in a growing state, and upon seer-wood • but the interference of other occupations has prevented a continuance of the inquiry. It cannot, however, but le d to results curious in themselves • and I therefore recommend it to the notice of all students in vegetable economy, as well as to those who love that noble science, STRUCTURE OP WOOD, &C. 333 science, and feel a gratification in being able to remove the veil ?aP an? ?oIa" ,,..,. . • > ,, tile parts in under which the mysterious operations of nature are concealed, wood. The particular object which I bad in view in exploring the structure of wood, have led me by a way by no means likely to be fertile in interesting discoveries • but I have begun the work, and feel myself bound to complete it, in preference to every other consideration. These fascinating researches, I am aware, have already carried me too far, and I must now resign them into the bands of others, in order to fulfil my engage- ments. This T do most cheerfully, and it will give me the greatest pleasure to behold a field too long neglected once more broken up. Section IV. Of the Quantities of Water contained in Woods considered as dry, or Seer- Woods. Wood is an hygrometric substance, and when exposed to the atmospheric air, always imbibes a visible quantity of water; varying, however, with the temperature and humidity of the air. If the moisture in the wood were confined in vessels so con- structed as to be totally impervious to watei, the fabric of the wood would be uniformly the same, with the exception only of the variations caused in its dimensions by change of tempera- ture j in which case it would be very easy to determine the quantity of water contained in the wood, when the specific gravity of its solid parts was known. But as the bulk of all woods is considerably diminished in drying, the experiment is rendered rather prolix, though by no means difficult, and its results are clear and satisfactory. A few examples will suffice to point out the method to be pursued. The composition of the oak, in a growing state, at the be- ginning of September has been already given. In order to ascertain the change which this wood undergoes by the process of drying, I made the following experiment. From a faggot of oak, 5\ inches in diameter, which, covered with its bark, had been exposed to dry in the open air, for 18 months, I took a piece of rather more than an inch square, and six inches in length j it was good fire-wood, and seemed very dry. m This 334 STRUCTURE OF WOOD, &C. Saj) and vola- tile par s in dry wood. This piece, after being trimmed by the joiner, weighed 126*2 grammes, and displaced 157'05 grammes of water j its specific gravity was consequently 80357, and a cubic inch weighed 15*939 grammes. Forty-three shavings of this wood, six inches long, and hilf an inch broad, weighed 17'Q grammes ; but when thoroughly dried in the stove, they were reduced to 13*7 grammes. They were, therefore, prior to being put into the stove, composed of 13*7 grammes of solid parts, that is to say, of dry, or seer- wood, and 4-2 grammes of water. The results of this experiment indicate, that 100 kilogrammes of this excellent fire-wood contained 76 kilogrammes of seer- wood, and 24 of water ; which is, probably, the ordinary state of the best fire-wood sold in the timber-yards of Paris, and all other places. Were the wood to be kept for several years, in a dry place, secured from the rain, it is possible, that it might become dry to such a degree as to contain only about 12 per cent, of water, and 88 of seer-wood. But it will appear in the sequel, that wood of any kind, exposed to the atmosphere, could never be- come more dry, on account of its hygrometric quality, which it constantly preserves. The following are the constituent parts of a cubic inch of fire-wood employed in this experiment : Ligneous parts, or seer-wood 0401 66 cubic inch, Sap, or water 0-18982 Air , 040852 00000 'J'hus we are enabled clearly to demonstrate the difference, between the oak in a growing state, and the same kind of wood after it has been felled and dried in the air, secured from the rain, for 18 months. In a cubic inch of oak, in a growing state In a cubic inch of the same kind of wood, after it had been felled and dried for J 8 months*... ., . , } Dry wood. Water. 039353 0-36122 0-40166 04 8982 Air. 0.24525 0*40852 By LIFT FOR CANALS. 335 By comparing the relative quantities of seer- wood contained in a piece of timber while in a growing state, and in the same timber after it has been dried, we may ascertain how much its fabric has shrunk by dessication. It appears from these experiments, that the oak sold in the timber-yards of Paris, for fiie-wood, contains rather more than one- half of the sap which it formerly had, in a growing state. I have made several similar experiments upon other species of wood 3 but their results are better calculated for exhibition in a table, than for circumstantial detail. (To be continue I.) III. Description of the perpendicular Uft erected as a Substitute for Locks on the Worcester and Birmingham Canal at Tardebig, near Broms grove. By Air. Woodhouse. From a printed Letter of Mr. Edward Smith, of Birmingham! and \he Re- ports of W. Jessop, Esq. THE whole of the machinery is under cover ; and we Machinery entered the building at the lower level of the canal, where forrawoi? a«d i J ? r i ii. , t • lowering the appearance of a number of large wheels, rods, and chains, boats upon seen in perspective, had a very striking and pleasing effect. canals ui(,,ont We walked by the side of an oblong trough or vessel, filled pence of wa- with water, large enough for a canal boat to float in. Tbis ter » by reservoir of water, with the canal boat, weighs sixty-four tons, and is suspended by eight rods and chains over as many large cast-iron wheels or pullies, which are balanced on the other side of the wall by an equal number of square frames, loaded with brick-work, or other heavy materials. After examining the lower structure of the building and machine, we got into an empty boat which floated in the reservoir, and were slowly raised to the upper level of the canal, without any noise or jarring of the machinery, by means of wheels and pinions on the other side, which were worked by two men with great ease ; it took about three minutes to ascend twelve feet, the difference be- tween the two levels. When the trough is thus raised to th« peccssary height, the paddles at the end., which are ingeniously con- 336 "FT FOR CANALS. Machinery contrived for the purpose, being drawn up, a communication aarf'^DwerinK is made betwe€n lne water in the *ro»gh and that in the canal, boats upon and the boat passes from the trough into the upper level of canals without tne canal, to pursue its course. In case a boat be ready in the the same ex- .... - J pence of wa- upper level, it is, in turn, floated into the trough ; the commu- Jflfc" by nication is then stopped by letting down the paddles into their places, and the machine is made to descend by the same means to the lower level of the canal, where, by similar paddles, the boat is released to proceed on its journey. Whether the boat be loaded or empty, it makes no difference in the weight ; for, as the machine is kept filled to a certain height with water, the boat, on its entrance, displaces just as much of this fluid as is equal to its own weight, I had previously formed a very erroneous idea of the ma- chine, and fancied it was complex and might be easily injured, and thus rendered useless ; but, so far from being complex, nothing can be more simple j the wheels, rods, and chains are strong enough to bear a far greater weight ; and if one-half of the number were removed, or could be supposed, by any acci- dent or design, to be out of order, the remainder would do the work ; and if the pinions, &c. should, by any means, be de- ranged, the machine, with little trouble, would act without them, the reservoir being balanced by the weights suspended. The great desideratum upon this canal is to procure water sufficient to answer the purpose of navigating down to the Severn. In case the six feet locks are adopted, the water must -be raised, by steam engines, from the Severn, and thrown back for sixceen miles, to the summit at Tardeblg. Thus there must be an immense expence incurred in the construction of such a number of engines as would be requisite fo'r this pur- pose, and also in the consequent charges for the supply of fuel, repairs, and the regular working the engine. This may easily be calculated from the allowed data. But, in case the lifts should be adopted throughout, there will be very little waste, of water, perhaps not so much as is constantly forcing its way through, or under a canal lock gate, when the lock is worn, or shaken by accident or mismanagement. The expence of erecting these perpendicular lifts must be, however, necessarily, very great, besides the constant expence of two or more men stationed at each, to work it. The pre- sent LIFT FOR CANALS. 337 gent lift is only twelve feet, and by way of experiment : for the Machinery Committee, in the first instance, did not choose to rnn too ^'JJJUJSng great risk j but the machines may be adapted to raise twenty, boats upon thirty, or any number of feet by greater length of chains, and J^^jJ^ adequate building to suit the levels, at a much less proportionate pence of water expence than in shorter lifts. To what extent this may be as bv lock8' carried, prudence and experience must dictate ; and, therefore, whether the expence of the perpendicular lifts, or the old sys- tem of lockage, with the expences of procuring water, be greater, it would be improper for me to give an opinion. In the course of conversation, many circumstances, highly favourable to his plan, were mentioned by the Inventor, which appeared to me to have great weight. By the old plan, each of the locks must have the same fall, and in each range they must be built near to each other, so as to be under the eye of the lock keeper j of course, instead of adapting them to the nature of the country, a great expence must unavoidably take place in the forming the land to the lock. This will not be the case with the lifts j being quite distinct from each other, it will not signify whether they be close, or one or six miles asunder, nor whether they lift 12, 20, or 30 feet. They may be accommodated to the nature of the country through .which the canal passes, will require much less land, and may be placed, probably, in situations where the land is of least value : the canal, for the same reason, may vary its course ac- cording to circumstances, which cannot be the case in the old f system j and when we consider the great price of land in some situations more than others, the saving to a Canal Company, in this respect, must be very great. As soon as one life is finished in a canal, it may be used, and a great saving made in water carriage to the remaining works, and perhaps the tonnage constantly increasing, which is not the case in the lock system/ which cannot be used to much effect till the steam engines are completed, and the water brought to the highest level. And if any considerations should be thought to stand against their general adoption in all circumstances, still the lifts would be of value j wherever water was scarce, and the lock system might be followed in situations where it was in plenty. At the time I am writing, I have before my eyes, 150 yards from 338 LIFT FOR CANALS. Machinery for from my house at Bordesley, a large fire engine, which till of lowem/1 boits late was an insufferable nuisance to the neighbourhood, by the upon canals immense volumes of thick black smoke it was pouring out, without the night and day, without intermission. This inconvenience of saino expesoe 4. . . . of water as by tne smoke has been lessened, in a great degree, by a contrivance locks, jn the management of the fire place, which ought to be adopted in all such cases. When I observe this engine employed solely in throwing back water to the upper level of the Warwick canal, for the floating of the boats, up and down through half a dozen locks, within the space of half a mile, I cannot help considering, that had the lift been known and applied, the canal might, at a little expence, have been continued on a level to the place where the fire engine is constructed,the expence of working the engine and all the lockage saved, and the boat, by one lift removed from one level to the other; the first cost of the lift, no doubt, would be great, and then you have said nearly the whole ; no fear of dry seasons, the reservoirs and feeders being sufficient to supply the loss of water from exhala- tion by the summer sun. Again, to look at the Birmingham canal at Smethwick, with its fire engine, reservoirs, and double range of locks— to what advantage might this machine be applied in such a situation 1 Plata VIII. Is a perspective view of the internal pajt of the ma- chine, when viewed from the lower level of the canal. The sur- rounding walls are taken away to avoid confusion : the centre wall is also broken off, at the nearest end, in order to shew the manner in which the balancing weights, at the back,are suspend- ed. The better to display the construction of the trough, it is raised five feet above the lower level j the dimensions of it are as follows ; length 72 feet — breadth 8 feet— depth 4 feet 6 inches, til outside measures. It is composed of planks, 3 inches thick ; its weight, when filled to the proper height with water, is 64 tons. The paddles, and their appurtenances, are marked as clearly as the nature of the case would admit ; a further explana^ tion of them, will be found in the references to figures 2, 3 and 4, Plate IX. From the. corners of the trough, rise four strong posts, 12 feet high, in each of which is a groove, which receives the respective paddles. Parallel to these, are similar posh, in which slide the paddles of the qanal. When a boat is to be introduced at the lower LIFT FOR CANALS. 339 lower level, the narrow space between the paddle of the trough Machinery for and that of the canal, is first filled with water, by opening a raisi"R lind * -9 . lowering boats valve, the situation of which is pointed out by the letter H, in upon canals fig. 2 and 4, Plate IX. ; the lateral pressure of the water against wltnowt the ° * ,1,7 same ex pence the paddles, is thus removed : The small chain, which hangs 0f water as by down between the upright posts, the lower part of which is 'ocks. double, is then linked to the hooks of both paddles, and by means of the crane near the end, they are drawn up together, and the boat floats into the trough j the paddles arc then drop- ped, and the trough raised to the upper level, when the boat is liberated by opening the paddles at the contrary end. A similar operation takes place, when a boat is required to descend from the upper to the lower level. Plate IX. Figure 1, a section of the end of the machine ; this clearly shews the principle by which the weight is raised, viz. that of the simple pulley, where the weight suspended on each side being equal, a force sufficient to overcome the unavoidable friction being applied, puts the whole in motion either way. A /4 represents the section of the trough, suspended from the iron beam C D C, by rods, the lower ends of which are fasten- ed by screws and nuts at B B, and the upper ends are fixed in the same manner at C €. From the centre D of the beam CDC, proceeds a very strong double chain D D d E, passing over the wheel H H. From the end E hangs an iron rod E FG, which passes through a thick square platform of oak at G, loaded with brick- work ta the weight of eight tons j this is the case with each of the others j the weight, therefore, of the whole, is 64 tons, being x equal to that of the trough, which they hold in equipoise. // H3 a cast-iron wheel, 12 feet in diameter, one of the eight which are seen in Plate I. IK, the centre wall, 30 feet high. From L, under the centre of the trough, is suspended a chain, which is loaded at equ.il distances with blocks of iron, 1, 2, 3, 4, 5 ; the weight of them is equal to as much of the chain and rod DdEFG, as hang in a perpendicular direction. The weights F G, are provided with similar chains, so that, as in the present instance, when they are at the lower level, the opposite blocks are called into action, and counterbalance the force of that portion of chain and rod, extending from d to G, while the blocks 340 LIFT FOR CANALS. Machinery for blocks suspended from G He inactive in the cavity M N: the raising and contrary is the case when the trough is sunk. lowering boats _.. . - , , ,, . , , . upon canals Figure 2, is a section of the paddles, &c. of the upper level. without the y{ay fti} the two perpendicular posts, containing the grooves, in of water as by wk*cn tne paddles CD slide. E F, small wheels at the Iwdtfc extremities of the posts 5 these, by rolling against other surfaces, contribute to regulate the ascending and descending motion of the trough. This is more distinctly seen in Figure 3, which is a profile of this part. G G, is the bottom of the canal, which projects a little beyond its paddle, in order to fill up the space between the bottoms of the two paddles, through which the water would otherwise escape. The side spaces are filled up by square pieces of wood, slide against strips of thick felt 3 thus rendering the whole com- pletely water-tight. H, the small valve, by withdrawing which the space between the paddles is filled with water. Figure 4. A plan of the situations of the paddles in the grooves j which is sufficiently explained by comparative re- ference to the other plates. Plate X. gives an elevation of the back of the machine, shew- ing the eight wheels B 1, H 2, &c. the chains and rods D E F, and the poise weights FG. Here also the external building is removed, the centre wall alone remaining, in the interstices of which the wheels revolve. The wheels No. 2 and 7, are toothed through twelve feet of their circumference, and by means of these teeth, they are acted upon by the wheel-work, which this plate also exhibits, //are the two winches by which the pinions and wheels K K, L Ly M M, N N, 0 O, are turned, and sufficient power is thus acquired to move the wheels H H 5 this is effected by the teeth of the pinions O 0> meeting those of H 2 and H J j these two being connected by the common axis P P, their motions necessarily correspond. On the sides of the weights F G, are small projections, which slide into grooves, constructed in the upright posts Q R. By means of these grooves, and the regulating wheels E F, in figures 2 and 3, Plate II. the perpen- dicular motion is rendered so perfectly true, that it was judged unnecessary to give the wheels H H, any hollow j the chains consequently move on flat surfaces, depending only on the mathematical truth of the work. Tht LIFT FOR CANALS. 341 The lines S, T, point out the situations of the lower and JJgJjJjg^ upper levels of the canal, between which, as was before lowering boats observed, the fall is 12 feet. u?°.n cf"ah _ without the W. H. SMITH. same cxpence of water as by Since my letter was first written a number of improvements locks, have been made in the perpendicular lift by the ingenious pro* jector, to prevent the chance of accidents to which new schemes are exposed, and also to obviate several objections that have been industriously circulated against the machine. An apparatus has been added, which effectually prevents the sudden motion of the machine, in case any accident should happen while the conductor is at the lower level, and which renders it impossible for the weights to descend, till the paddles of the conductor are adjusted. Two pumps have also been introduced, which regulate the speed of the machine, and by which the conductor may pass from one level to the other, without any manual labour ; and the conductor and paddles are now so guarded, that they cannot receive injury from the violent entrance of the boats. Owing to the numerous delays, the tunnel at Tardebig was not completed so soon as stated, and the consequent trial of the lift, as expected by the proprietors, could not be effectually made previous to the general meeting of January 1, 1811. This, and other circumstances, induced the general meeting to pass resolutions, by which it was determined, (though so much expence had been incurred) to abandon the scheme in toto, and finish the canal by means of locks j chiefly, however, on the ground, that it was impossible (as alleged) for the lift to pass nearly the number of boats requisite, when the canal should be completed. Several respectable proprietors, not satisfied with this determination, and concerned that a plan, in their opinion, replete with advantage to the canal and the public at large, should be abandoned almost without trial, have come forward at their own expence, to make a complete trial of the machine, and its capability to do what might be requisite. This trial was continued under the patronage of these gentle- men for nearly a month, by means of three boats constantly working upward and downward, for a given period in each day, one of 20 tons, one of 15 tons, and the other empty, being the usual J42 LIFT Ft>R CANALS. Machinery for usual proportion in the common traffic on canals. The result lowe"fuH?oatt of thls wil* surPrize manv persons who had formed a very upon canals different idea of the power of the lift, and must be very gratify i without the ing to the inventor, who, whether the scheme be adopted or of water as by abandoned by the proprietors, will be able to refer to the solid locks. rest 0f experiments thus laid before the public. The result of the experiments to the day of publication I subjoin E. SMITH. March 18, 1811. Feb. 25, 1st Day, 50 Boats passed, in 6 Hours 29 Min. in 8 Hours 10 Min. in 9 Hours 8 Min. in 5 Hours 1 Min. in 6 Hours 40 Min. in 6 Hours 48 Min. in 6 Hours 52 Min. in 5 Hours 16 Min. in 6 Hours 21 Min. in 6 Hours 22 Min, in 5 Hours 20 Min, in 5 Hours 25 Min. in 11 Hours 46 Min. in 7 Hours 20 Min. in 5 Hours 41 Min. in 12 Hours, in 5 Hours 37 Min. in 5 Hours 54 Min. in 12 Hours, in 5 Hours 42 Min. in 8 Hours. In 6 Hours 26 Min, in 6 Hours. (Signed) WILLIAM JOHNSON. 26, 2nd 60 ditto 27, 3d 70 ditto 28, 4th 37 ditto Mar. 1, 5 th 50 ditto 1 2, 6th 50 ditto — 4, 7th 50 ditto 5, Sth 40 ditto 6, 9th 51 ditto 7> 10th 48 ditto 9, 11th 41 ditto 11, 12th 40 ditto 12, 13th 100 ditto 1$, 14th 53 ditto 14, I5th 50 ditto 15, 16th 110 ditto 16, 1/th 50 ditto 18, 18th 50 ditto 19, 19th 113 ditto 20, 20th 50 ditto 21, 2tst 68 ditto 22, 22d 60 ditto — 23, 23d 62 ditto Curious FIGURE OF TREES ON ICE. 34 IV. Curious Fact of the Outlines of Trees, accurately sketched on the surface of the ice on the Bog Lakes of Ireland, In a Let- ter from John Chichester, M. D. of Bath. To W. Nicholson, Esq. SIR, THE account given in your Journal for April last, of the Trees buried remarkable appearance of the ice in a pond in which a «°dclLj[£eg man lay drowned, brought to my recollection the following are marked analogous, and perhaps no less curious phenomenon, occurring J?v t,ie ,10ar in the Bog Lakes of Ireland, communicated to me some years jng jess per. since by the Rev. Mr. Mangin. The following are Mr. Man- «l»iible o*et ; , « them, gin s own words :— "On the 24th of December, I8O9, 1 was in company with a gentleman from Ireland, who mentioned what appeared singular, and was then new to me : speaking of the bogs in his neighbourhood, and of the large trees so frequently found in them, he said, that at those periods of the year, when the hoar frost fixes on the surfaces of the small lakes with which those morasses abound, he had repeatedly observed the form of a tree, (lying, perhaps, at a depth of fourteen or twenty feet beneath,) sketched most accurately on the ice above j that is to say, its iength, breadth, and ramifications denoted by the frost not settling with equal force on those portions of the fluid under which the tree was extended, while the congealment was every where else more, dense and complete." The gentleman added, that it was well known to the country people, who were accustomed to search for and find timber when thus indicated. The trees discovered in these places are of various kinds, oaks, elms, &c. and very commonly yew trees of vast size, their position invariably horizontal." Without any comment, I beg leave to subscribe myself. Sir, Your obedient Servant, JOHN CHICHESTER, M. D. And Physician at Bath. May nth, 1813. 344 - GILDING. Annotation. Though the indistinct outline of a large object not deeply immersed in a small stagnant pool, may seem to be well ex- plained by the observations given at page 304, of our XXXIVth vol. Yet the same principles do not appear adequate to shew why the ramifications of a tree buried twenty feet in a bog, should be neatly figured upon the ice of water lying on its sur- face. None of the general operative powers with which we are acquainted, present a solution of thiseffect. Heat, electri- city, gravitation. Of these the latter only is known to act in the perpendicular ; but this affords no ground for the remotest conjecture. It would be desirable to know whether the ice of the outline were different in texture from the rest. — W.N. V. On Copper Wire, guilt with Brass. In a Letter from a Cor- respondent. To Mr. Nicholson. SIR, I HAVE been informed, that the gilding of copper wire by means of brass is carried to great perfection in Germany. Perhaps it may also be the case in England j respecting which I should be glad to hear from your correspondents. The facts, as stated to me, are, that copper wire, coated with brass, is ca- pable of being drawn out to the fineness of a hair j much finer than copper alone -, that it is used for making gold lace, and the process effected in the humid way, as follows : — Take of zinc one part, and of mercury twelve parts — make a smooth soft amalgam, to which, if a little gold be added, it will be better. Clean the copper very nicely with nitric acid -f put the amalgam into muriatic acid, and add argol or crude (not purified) tartar. Boil the clean copper in this, and it will be very finely gilt. Epaulets and gold-coloured trinkets are thus made very beautiful. Query. Would this be an improvement in pins ? I am, Sir, Your Constant Reader, M.M.B. INDEX. -nL* HIS description of simp'e appa- ratus for distillation, 192. Achromatic glasses, 117. Acid, fluoric, combinations of, 8i. Acids, muriatic and oximuriatic, 42. 68. 264. Adventurer, an, to the interior of Africa, 134. Aerostation, accidents in, 74. Africa, travels in the interior of, 134. A. H. E. on certain ready processes for computation, supposed to have been invented by the American boy, (see p. 5,) exhibited in London, 193. ■ ■■ ■ , answered, 291. Aikin, A., Esq., on a bed of green- stone, in Staffordshire, 78. Air, discovered in trees, and in seer- woods, 324. Alcohol, congelation of, 166. Allen and Pepys, Messrs. 201. Alpine Plants, bank for the culture of, 24. Amianthus, improved mode of manu- facturing, 311. Analysis—of the urine of different ani- mals, 1. Of the sepia of the cuttle- fish, 35. Animal heat, experiments on, 199. Supplement, Vol. XXXIV.- Antimoniimi, oxides of, 241. 313. " Arithmetical computations, 5. 193. 193. 291. Arrowsmith, Mr., his extraordinary large map of England and Wales, 150. Arsenic, test for, 17 4. Atmospheric electricity, 126. Aurora borealis, its appearance and disappearance, 196. Automaton, a speaking, 229. Azote and chlorine, explosive com- pound of, 180. 276. B. B. query from, to O., relative to the extraction of the square and cube roots, 311. Bake well, Mr., 80 228. Bank for the culture of Alpine plants, 24. Barytes, muriate of, experiments on, to ascertain its action on the animal system, 9. Beaver, urine of the, analysis of, 3. Beccaria's observations on atmospheric electricity, 126. Berthollet, M. 50. 54. Berzelius, Professor, his explanatory No. 160. A a 346 INDEX. statemeut of the notions or principles upon which was founded the syste- matic arrangement, adopted as the basis of an essay on chemical nomen- clature, 14*. 154. '240. 313. ■ , correction of an error of, 312. Birds, urine of, 1. "Biouomia: opinions concerning Life and Health, 73. Bittorf, M ., his fatal aerial voyage, 75. Black, Dr., 209. Blow-pipe, for statics, 190. Bologna, M., his aeronautic disaster, 74. Books, 6cc. recently published, 72. 151. 331. Bostoek, Dr. 69. 265. Bouvard, M., his discovery of a new comet, 76. Brain, the, its influence on the genera- tion of animal heat, 199. Brando, Mr., 31-2. Bristol, lime-stone strata in its vicinity, 77. Brodie, B. C, Esq., on the action of poisons on the animal system, 9. ( on the influence of the brain in the generation of animal htat, 199. Bruck, M. De, 148. Brumon,:'Mr. W., his description of an improved pump, 64. Buchan, Dr. A. P., his " Bionomia,"73. Bucholz, M.,241. Burton, Mr., lc<0, Buxton, Dr., 79. c. Caldeiras,or hot fountains in the Azores, 305. Camera obscura, periscopic, 26- 100. Canals, a hft tor, in lieu ol locks, 3.35. Canton, M.,*15. Cavendish, 50. Chamberlaync, Mr. W., his t4 Tyroci- ninm Medicum,"74. Charcoal, quantity of, to be obtained from wood, 319. Chemistry, comparative, recommend- ed,!. , explanatory statement of the principles of, 142. 154. 240. 313. Chichester, Dr., communication from, of a curious fact of the outlines of trees, accurately sketched on the surface of the ice, on the bog-lakes of Ireland, 343. Chlorine and azote, explosive com- pound of, 180. '276. Chondrometer, an instrument for as- certaining the quantity of grain by weight, 198. 312. Chronometry, 146. C. L. his remarks on a statical blow- pipe, 1 90. Cloth, incombustible, 311- Clovelly, in Devonshire, rocks of, 309. Coffee, qualities of, and art of making it, 66. Colburn, Zerah, his remarkable powers of computation, 5. Observations on, 193. Vindication of his claims, 291. Comet, new, 76. Computation, extraordinary powers of. in a child, 5. Kemarks, 193. Vin- dicatien, 291. Congelation of Mercury, by means of ether, 119. Alcohol, 166. Conybeare, W., Esq., on the origin of a remarkable class of organic im- pressions occurring in nodules of flint, 222. Conybeare, Rev. I. J., on the rocks oi Clovelly, in Devonshire, 309. INDEX. S*7 Copying, art of, or of multiplying co- pies, 113. Cornwall, ceolouica' observations on, 221 . Economy of the mines of, fl9& Corrosive sublimate, its effects on tiie animal system, 1.3. Cotte, M., on the appearance and dis- appearance of the aurora borealis, 196. Crawford, Dr., 209. Cube-root, query relative to the extrac- tion of, 311. Cumberland, G., Esq., on some lime stone strata, near Bristol, 177. Cumberland, sand tubes found at Drigg, in the county of, 76. Cuttle-fish, observations on, 34. D. Da Casta, 222. Dalton, Mr., 50. Davis, Mr. W., 80. Davy, Sir H., 46. 69. 81 . 180. Davy, J , Esq., 42. '267. His account of an experiment to ascertain if water is contained in muriatic acid gas, 68. Observations on, by Mr. Murray, 264. — — — — , bis account of some experi- ments on different combinations of fluoric acid, 81. Dccandole, M., on the tendrils of •fonts, 39. Det omposition of gases by solar light, 220. Delambre, Chev.,93. Delametherie, Dr., 142. De Luc, M.,74. De Marti, 50. Derbyshire Peak, models of, 226. Dessaignes, J. P., on the origin and generation of the electric power, 211. Devonshire, granite tors of, 307. — . rocks of Clovelly, 309 Distillation, apparatus for, 19^. Draining of Land, 218. Drigg, in Cumberland,sand tubes found at, 76. Dupuytren, M. 208. Dusseu, M., 50. Earth, figure of the, 90. Electric power, generation of, tit. Electricity, atmospheric, 126. Electro-chemistry, theory of, 154. Engenhansz, 50. England, trigonometrical survey of, 246. Escapement for pendulum clocks, 136. " Essay on Vision," 73. Evans, O., his rules for discovering new improvements, with exemplifi- cations, 107. Eudiometry, 50. Explosion by solar light, 220. Explosive compound of chlorine and azote, ICO. I*T6*. F. Falconer, 50, Farey, Mr. J., 226. , on the connection between shooting stars and large meteors, and proceeding both from terrestrial and satellitulae, 298. Fiddler, Captain, 150. Fluoric acid, experiments on, 81. Fluids, elastic, contained in wood, 319. Fontana, 50. Forster, Mr., 298. Franklin, Dr., bis method of multiply- ing copies, 115. Freezing, remarkable phenomenon in, 301. See Congelation. Gas, muriatic acid, water in, 68. 264. Gases decomposed by solar light, £20. Aa 2 348 INDEX. Gay Lnsmc, M., 40. 31. 317. Geological Society, proceedings in, 76. 2? 1.306. Officers for the present year, •:.:;. Geology, lectures in, 220. Gianite tors of Devonshire, 307. Giavity, specific, of the solfd parts of wood, SCI. Greeve, 519. 324. Greenstone, bed of, in Staffordshire, 78. Gregory, Dr. Oliiithus, in reply to Don Joseph Rodriguez's animadversions on pai t of the trigonometrical survey of England, 216. H. Hall, Mr. E., description of his models of the high Peak of Derbyshire, 226. Hardening steel, experiments on, 31. Hatchett, Mr., first suggested the trial of magnesia in calculous diseases, 312. Heat, animal, experiments on, 199. , produced by the combustion of wood, 319. Henley, Mr. 130. Henry, Dv. W., 71. 267. __«__ } ius additional experi- ments on the muriatic and oximu- riatic acids, 42. •, explanation from, 312. Hesleden, Major B., his account of the drainage of a piece of morass land in Yorkshire, 218. Hisinger, M. De, 240. " History of the Royal Society," 73. H. K. on the interruption produced by the maintaining weight in the rate of a clock, when nea» the pendulum, 146. Hope, Dr , 69. 265. Horn, Mr. A. his " Essay on Vision," 73. Hornslcy, Professor, 1 16. Hot fountains in the Azores, 305. Howard, Mr. U, 126. Howard, Mr., see Meteorological Journal. Human figure in ice, a remarkable phe- nomenon, o()l. Humboldt, 50. Hutton, Mr., his notice respecting some experiments on the freezing err" alcohol, 166. Hydrography, 150. I. Ice, remarkable phenomena on the sur- face of, 301. 343. Improvements, rules for discovering, 107. Ingenhousz, M., 215. Ink, incombustible, 311. Invention, rules for, 107. Irton, E. L., Esq., on the sand-tubes found at Drigg, in Cumbeiland, 76. J. Jessop, W., Esq. 68. 335. Jones, Mr. W. on Dr. Wollaston's. stated improvement of the camera obscura and microscope, 100. K. Kemp, Mr. G., on the sepia, or cuttle- fish, 34. KempelUn, Baron, account of his speaking machine, 229. Kirk, Mr. R., on the explosive com- pound of chlorine and azote, 180. 276. Knight, T. A., Esq., on the motions of the tendrils of plaots, 37. Kratzenstein, 230. Ladriani, 50. Lagerhjelm, M., 240. INDEX. 349 Lambton, Major W., observations on Iris measurement on the meridian, 92. Laplace, iVt . , 809. Lapland mountains, geological survey of, 148. ' Lavoisier, M., 209. Lenses, achromatic, 117. Leroy, M., 215. Leslie, Mr., 51. , his method of freezing, 119. Lift for canal*, a substitute for locks, 335. Limestone, remarkable interrupted vein in, 77* Lion, urine of the, analysis of, 2. Liquids, &c. contained in wood, 319. Locks on canals, a substitute for; 335. Lovi, Mr., on the advantages of mea- suring fluids by weight, 230. Lydiatt, Mr. E., his practical experi- ments on hardening steel, 3i. M. Mac P. ride, Dr. 52. Mac Cnlloch, Dr., on an interrupted vein in lime-stone, 77. _, 1 on the granite tors of Devonshire, 307. On the Use of Staffa, 309. Mackenzie, Sir G. 69. Magellan, 50. Magendie, M., 201. Malpi^hi, 319. 324. Mangin, Rev. Mr., his account of the figure of trees sketched in the ice, on the bog-lakes of Ireland, 3 13. Manners, Dr. J., his experiments on putrefaction, 49. Map of England and^Wales, an extra- ordinary large, 150. Marcet, Dr. A., his account of some experiments on the congelation of mercury, by means of ether, 119. _ . f on the use of nitrate of silver, for the detection of minute portions of arsenic, 174. Marum, M., 215. Measurement of fluids by weight, 230. Mechain, M., 94. Mercury, congelation of, 119. Meridian, measurement of three de- grees of, 90. Merino Wool, Rritish, 121. Metallic oxides, 249. 315. Meteoric stone, 76. Meteors and shooting-stars, 298. Meteorological Journal for November, 62. For December, 140. Eor Janu- ary, 178. For February, 296. Microscope, periscopic, ^6. 100. Milb'ura, Mr., 74. Mines of Cornwall and Devon, 2-24. Mitchell, Dr., 53. Mountains, vegetation of, 16. Mountains of Lapland, travels among, 148. Mudge, Lieut-col., 247. Observations on his measurement of three degrees of the meridian, 90. Muriatie acid, additional experiments on, 42. Muriatic acid gas, water in, 68. 264. Murray, Mr. J., 42, 69. f on the existence of combined water in muriatic acid gas, 264. N. Nomenclature, chemical, principles of, 142. 154. 240. 313. o. O. on arithmetical computations, 195. A question to, 31 1. 6: ides, metallic, 240. 513. Oxiinuriatic acid, additional experi- ments oh, 42. 350 INDEX. Paper, incnnbustible, 311. Park, Mungo, 134. Parkinson, Mr. Payne and Ovenden, Messrs., their por- table instrument for ascertaining the quantity of giruin by weight, 198. Peak of Derbyshire, models of, 296, Perpenti, Madame, her improved mode of manufacturing incombustible cloth and paper from the acanthus, Si 1. Periseopie camera and microscope, 26. 100. Philips, Mr., on the veins of Cornwall, 221. Philosophical Transactions, account of, 72. Plants, motions of the tendiils of, 37. Play fair, Mr., 69. Poisons, their action on the animal system, 9. Pon , M., his discovery of a new co- met, 76- Pontine marshes drained, 80. Porret, Mr. R., jun. on the explosive c« mpound of chlorine and azote, 180, 276- Priestley, Dr., 50. 35. Pringle,Sir J., 5* Printing, benefits of the art of, 113. Prior, Mr. G-, his description of a re montoire escapement for pendulum clocks, 136. Proust, M., 241. Publications, new, 72. 151. 2.4. Pump, improved, for raising water from wells or mii:es, while sinking or making, 64. Putrefaction, experiments on, 49. R. Rallier des Ourmes, M.., 194. 291. Ramond, M., on the vegetatiou of high mountains, 16. Rathoff, M., ',40. R. B. on the juvenile results of Bec- cariass observations upon the elec- tricity of the atmosphere during serene weather ; together with those of Romayne and Henley, 126. Rice, improvement in hulling and cleaning, iff. Reid, Mr. T., 1 16. Robertson, M , his invention of a speaking automaton, 229. Rochon, Abbe, hi* method of multi- plying copies, 115.— On achromatic lenses, 117. Rodriguez, Don J., on the measure- ment of three decrees of the meridian, byheut.-col. W. Mudge, 00. Reply to his animadversions on Dr. O. Gre^oiy's Tii^onometsical survey of England, 246. Roentgen, his recent travels in the inteiiorof Africa, 134. Rnget, Dr., 174. Romayne's apparatus for ascertaining the degree of atmospheric electri- city, 1-9. - Root, cube and square, extraction of, 195. 311. Rumford, Count, on the excellent qua- lities of coffee, and the art of making it in the highest perfection, 56. , on the structure of wood, the specific gravity of its solid parts, and the quantity of liquids and elastic fluids c ntained iu it under various circumstances : the quantity of charcoal to be obtained from it, and the quantity of heat produced by its combustion, 319. S. Sadler, Mr., his perilous aerial voyage, 75. Saint, Mr. W., his vindication of the claims of the American boy to extraordinary talents and original discovery, 291. St. Michael's, hot fountains in, 305. INDEX, 351 Salisbury, R. A. Fsr». his translation of M. Ramond's , aper nn Ihe vegeta- tion of high mountains, 16. Of M. Thouin's dtscr.pt. >n of a bank for Alpine plants, 24. Sand-tubes found at Drigg, in Cumber- land, 76. Scheele, 50. Schulze, M., on the comparative strength of men and horses, applica- ble to the movement of machines, <233. Scientific Institution, Lectures at, 79. Scientific news, 7 '2. 148, S21. 306. Seebeck, M., on the action of coloured rays on a mixture of oximuriatic gas and hidrogen gas, 220. Seer-woods, sap and air contained in, 324. Sefftroud, M. 240. Seguin, 50. Sepia, or cuttle fish, 34. Sheppard, £. Esq. on the best state in which it is advisable to bring the British Merino wools to market, 121. Ships saved from sinking, improvement in, 112. Shooting-stars and large meteors, 298. Shute, Mr. T., 79. Singer, Mr., his electrical Lectures, 79. ■■ ■ ■ — , Strictures on his paper on shooting-stars, 298. Smith, Mr. E. his description of the perpendicular lift, erected as a sub- stitute for locks on the Worcester and Birmingham canal, at Tardebig, near Bromsgrove. 335. Snart, Mr., inventor of the Chondrome- ter, 312. Square-root, extraction of, query relative to, 311. Staffa, Isle of, geological remarks on, 309. Stars, scintillation of, 116. Statical blow-pipe, 190. Steam chimney, 138. Steel, experiments on the hardening of, 31. Strength of men and horses, applicable to the movement of machines, 233. Sylvester, Mr., 174. T. Tartar emetic, experiments on, to ascertain its action on the animal system, 12. Taylor, J., Esq., on the economy of the mines of Cornwall and Devon, 224. Tendrils of plants, their motions, 37. Test for arsenic, 174. Thenard, M., 49. 81. 241. Thomson, Dr., 50. , his " History of the Royal Society," 73. his " Annals of Philoso- phy," 121, , animadversions on his preface to the latter work, 1 51. Thouin, M. his description of a bank for the culture of Alpine plants, 24. Threshing, improvement in, 108. Tiger, urine of the, analysis of, 2. Traill, Dr. 69, 265. Trees, sap and air contained in, 324. , accurately sketched on the surface of the ice, on the bog-lakes of Ireland, 343. Trigonometrical Survey of England, defence of, 246. " Tyrocinium Medicum : or a Disserta- tion on the Duties of Youth apprentic ed to the Medical Profession," 74 V. Valenberg's journey for examining the mountains of Lapland, 148. Vauquelin, M., his comparative analy- ses of the urine of various animals, l. Vegetation of high mountains, 16. Volta, 50. S52 INDEX, u. Urine of different Animals, analyses of, 1. Wafeli,' 22*. Warming apartments, improvement in, 109. Water combined in muriatic acid gas, (38, IgaJ Water contained in woods considered as dry, or seer-woods, 3R3. Watt's copying machine, 114. Webster, Mr. G., his description of a Cheap and easy method of conveying steam and vapour up a chimney, M8. , y on the geology of the Isle of Wight, 306. 309. Wedsewood's art of copying by trac- ing-paper, 115. Wight, Isle of, geological observations on, 306. Wilson, Mr. W., on the explosive com- pound of chlorine and azote, 180. Winnowing, improvement in, 109. W. N. on the hardening of steel, S3.— On multiplying copies of writing, }1J. On the scintillation of the stars, 116. On large achromatic lenses, 117. On some passages on t)r. Thompson's preface, 151. On Mr. Button's experiments concern- ing the freezing of alcohol, 172. On a remarkable appearance in the ice of a pond in which a man was drown* cd, 301 ; and on a similar pheno- menon on the bog-lakes of Ireland, 311. Wood, inquiries relative to the struc- ture of, the specific gravity of its solid parts, and the quantity of li- quids and elastic fluids contained in it, under various circumstances ; the quantity of charcoal to be obtained from it ; and the quantity of heat produced by its combustion, 319. Woodhouse, Mr., his perpendicular lift, erected as a substitute for locks on canals, 335. Wool, British Merino, when best for the market, 121. Wollaston, Dr., 121. On a periscopic camera obscura and microscope, 26. Observations on, 100. z. Zambeccari, M., his death, 74. ERRATUM. Page 152, line 30, for " repertory," read * retrospect.*1 END OF THE THIRTY-FOURTH VOLUME. Printed b> G. SIDNEY, orthqnibcrland-slreet, Strand.