How the “Scientific American” is Regarded at the South—Manufacturing at Petersburgh, Va. j MESSES. EDITORS :—The annoucement in your paper, of January 30th, that you intend to devote attention during the j year to the subject of architecture and building, and the arti-. cle with illustrations in your last must be very acceptable : to the readers of the SCIENTIFIC AMERICAN, and will render I it all that the artisan in any department can desire. During the last twenty-four years, the paper has disseminated a vast deal of valuable information, which would not have otherwise reached the mechanics of the country. Its present size and I large circulation are proofs that your efforts to make it the paper of the age are fully appreciated. The writer was among the first subscribers, and I have oftentimes found in a single number ideas and information of far more value to me than the price of a years subscription. Members of my family, not interested in mechanical science, find also inter-1 esting reading in it. This being the general verdict, I cannot i be accused of attempting a puff, and being unknown to you, have no interest to do so. But I do want to impress upon the minds of the mechanics, here South in particular, the advantage it will be to them to take such a paper as the SCIENTIFIC I AMERICAN, if they wish to improve and keep posted in all that pertains to the industrial arts of our country. Many of your readers are interested in the publication of I statistical information of manufactures, such as the report of the President of the Augusta (Ga.), Manufacturing Company, given in full in your paper last month. I noticed it created a little stir here among the manufacturers. Stockholders in the cotton factories went into an examination of balance sheets, etc. There are seven or eight cotton manufacturing establishments in this city and immediate vicinity, which run about 23,000 spindles. Most of them appear to have done well, as I have found by inquiry, and while in search of information to meet the challenge of comparison from Georgia, I visited I the Petersburgh Cotton Mill, which has the reputation of I being one of the most complete and well-conducted cotton factories in the South. It has been in operation nearly three I years, and is filled throughout with improved machinery of American build (except a few pieces). It works admirably, and the excellence of the goods made does credit to the skill and superior taste of our American machine builders. I was told that a gentleman interested in importing foreign machinery, after seeing this factory, said it was folly to send abroad when such results can be obtained from our own make; and j I was permitted to copy from the Petersburgh Cotton Mill books the statement which follows. Your readers will readily see that the profits and the success of the Augusta company is not an isolated case. I did not ask permission to state j the aggregate amount made by this Petersburgh mill, as those interested, from figures here given, will clearly see that the Petersburgh Cotton Mill has done better in proportion to size of mill. I find the cotton cost the Augusta Company 19-98c. per lb., and as for wages paid, it cost them to manufacture 74c. per lb., or 2Jc. per yard. Their loss from waste was a little over 13 per cent.; their repairs cost over Jc. per lb. I. also find the cost of cotton used by the Petersburgh Cotton Mill, during same six months, to be 1999 cents per lb., and as for wages paid cost to manufacture per lb 63 cents, and per yard, l-53 cents; the loss from waste lOf per cent; cost of repairs, 1 cent per lb.; expense account I find smaller in proportion at the Petersburgh Cotton Mill; taxes and other outside items it is fair to presume, are equal at both places. The Augusta Company, as reported, run 505 looms, employing 507 hands, and turn off an average of 49 yards to a loom daily. This Petersburgh mill has 100 looms, employing 98 hands, and has averaged 46 yards to loom per day. The difference J in production of looms is accountedfor thus: The Petersburgh Cotton Mill makes fine sheetings, shirtings, and drilling, closer picked, and command a higher price consequently per lb. It may appear singular to see the price paid for cotton so I near the same; it is owing partly to both parties using cotton grown near their respective factories; and although the Augusta Company got a better grade of cotton there at same j cost, their loss in waste for working it exceeds that of the j Petersburgh Cotton Mill by nearly three per cent, which is no small item when cotton is high. From the foregoing statements it must be evident that the Petersburgh mill has a larger margin for profits, with the exception of -01 part of a cent per lb. in cost of cotton, every item in the process of manufacture is below that of the Augusta Companys re-i port. I state this not in a disparaging spirit, as this state- ment shows the Petersburgh Cotton Mill must have a great I advantage from having all new machinery in use. With this j fact before us, I am not disposed to pluck the laurels from the j brow of our Augusta friends. j Manufacturing South can be made a decided success. The I fine water powers in this place, Richmond and Predericks-j burgh, together with our climatic advantages, are unsurpassed, and offer rare inducement to men of capital and enterprise to settle in this old State of ours. VIRGINIA. I Petersburgh, Va. j j Gas from Gasoline more Dangerous than Coal Gas MESSRS. EDITORS :—A correspondent (page 86, current volume), wants, in justice to the gas machine men, an article on gas machines, or gas from gasoline. As I myself am the patentee of such a machine, and a very successful one, too, I might b e suppose J to belong to this class of men, and, therefore, cannot be suspected of being prejudiced against the gas machine. However, injustice to the truth, I must confess my conviction that the gas from gasoline produced by the so- called gas machines, is more dangerous than coal gas; this conviction is founded on theory and experience. The latter I need not describe; we see almost every day in the papers I the results of explosions produced by the intermixture of air with the more volatile products of petroleum, supposed to be removed by the distillation, but which are seldom sufficiently removed to make the so-called kerosene perfectly safe, or what I is worse, they are, for their cheapness sake, intentionally in- traduced by the dealers or retailers. The explosions produced by coal gas are comparatively very rare. ; The causes that gasoline vapors are more dangerous than coal gas are the following: 1. It takes a less quantity of gasoline vapor to make with air an explosive mixture than it takes of coal gas. 2. As gasoline vapor is heavier than air, it will fall to the ground and collect there; coal gas, however, is lighter than air, therefore it will ascend, and be more likely to escape through the air holes of the cellar, which are always at the top, and therefore give no occasion to the heavy gasoline vapors to escape, therefore they will collect. j 3. Coal gas will be detected by a strong smell, even when the smallest quantity is present a fraction of one per cent makes its presence known, therefore, long before the mixture with air has become inflammable. Gasoline gas has not the disagreeable smell, the smell is also weaker, and is so customary in localities where this gas is used that.its presence does not arouse any suspicion. 4. The coal gas has a strongly diffusive power in relation to atmospheric air, and will therefore be soon removed from i the source where it escapes; gasoline gas, on the contrary, has little of this diffusive power, and may form an invisible layer of say one foot high at the bottom of the cellar, which may remain there for hours, when the air is not stirred, very slowly mixing with the air, and ready to explode at the moment of contact with light. We must, therefore, conclude that to diminish the danger of explosions when gasoline gas is used, open air holes must be made at the bottom of the room, and when coal gas is used, at the top, in order to provide an effective means of es-escape to explosive mixtures of gas and atmospheric air. In both cases, however, openings are also required to admit air at the opposite ends of the room, in order to replace the escaping gas by fresh air, in short, all rooms where there is danger of collecting inflammable gases or explosive mixtures of these gases with atmospheric air, should be thoronp;h-ly ventilated. P. H. VANDKE WEYDB, M. D. New York city. To Ascertain the Power of a Microscope MESSRS. EDITORS :—If your correspondent G. W. M., by his question on the 108th page of your issue of February 18th, means to ask how to find what is the power of a given microscope, the following method may assist him : Place a smal object of known length, say from l-20th to 1-oOth of an inch on the stage of the microscope, and looking at this through the instrument with one eye, with the other look at a foot rule held at the level of the stage. With a little practice both may be seen at once, when, by dividing the space apparently occupied by the object on the scale, by the known length of the object, the magnifying power will be obtained. If the power is very high, the best object to use is a glass micrometer, which may be purchased for a dollar or two, of any optician, with lines ruled on it to hundredths or thousandths of an inch. The power of a telescope may be found in a similar manner by nailing a square of white paper an inch in diameter on a board fence or the side of a building. This square, seen through the telescope, will cover a considerable space on the fence as seen by the unoccupied eye. This distance reduced to inches will show the power of tliu instrument as before. A little difficulty is sometimes found in seeing both objects at once, but this is soon overcome, and the method has the great advantage of not requiring the separation of the lenses or any knowledge of the mode of their combination, which varies with different opticians. Middletown, Conn. W. E. HUMBERT. A California Saw Mill MESSRS. EDITORS :—Possibly the following may be of interest to your readers; at least it will give them an idea of our sawing business here. Our engine is 14 inches diameter by 18 inches stroke, running 130 revolutions per minute with 90 pounds of steam; built extra strong with large bearings; fly wheel 8-J feet diameter, weight 3,350 pounds, carrying a 16-inch rubber belt direct to saw arbor. Boilers, two in number, 42 inches diameter by 20 feet long, with two 14-inch flues. Smoke stack 30 inches diameter and 40 feet high. This engine drives one 60-inch and one 50-inch doublecircula r saws, one edger, one siding saw, one cutting-off, one picket, one lath saw, Hendys gang saws (four to six) running horizontal and cutting into the solid log from one to four inches, one Putnam planing machine, beside grindstones, sawdust carriers, engine lathe, and wood-turning lathe. With full head of steam all the above machinery can be driven at the same time. The edger and planing machine are driven from a shaft coupled on the end of the main saw arbor. We use Dunbars piston packing and the Giffard injector. Our object in arrangement of machinery was to have as few parts as possible, and everything direct acting. We cut 6,000,000 feet of lumber per year and have done so for the past two years. Five-sixths of it were redwood, and one-sixth pine which is very hard. The redwood is quite soft, something like eastern pine. We use Spauldings patent tooth saws, excellent for the sort of timber cut here. T.REBVES. Little River Mill, Little River. Mendocino Co., Cal. 151 The Crank and Rotary j MBSSKS. EDITORS :—My proposition to you in my first com munication was substantially as follows: 50 square inches of piston area and 80 lbs. of steam, 24-inch stroke, 100 revolutions per minute, creating 4,000 lbs. exertive force, less the friction, at the point of half stroke. What number of square [ inches of piston area will equal the above, if applied six-sevenths of the entire circle, under same pressure of steam and same leverage of crank ? In your editorial comments on page 54, current Vol. SCIENTIFIC AMERICAN, I find, first, that if I had been a constant subscriber to the SCIENTIFIC AMERICAN I would not have attempted to enter upon a path which has proved a failure to so many others, etc. In reply to this I j would say that I now have, bound and unbound, in my house more volumes of the SCIENTIFIC AMEKICAN, than the editor would be able to stand under if they were piled upon his i shoulders. Second, that I imagine a rotary engine. Here I beg to differ from you; I have a perfect engine all finished. Third, the steam must impinge upon the crank with equal force at every point in its revolution; here again I differ with you. I said six-sevenths of the entire circle. There again you say this cannot be done with the crank. If I apply the force 12 inches from center of main shaft and continue that force as stated above, is it not virtually a crank? You seem to have no faith in the cranks ever being economically super-ceded; I think different. If you have a propulsive force at tlie point of half stroke in the above described engine, you certainly have no force at either of the dead centers. Suppose 4,000 lbs. exertive force is applied to the crank pin at half stroke (12-inch crank) now drop this crank pin just half way towards the center of main shaft, and still keep the same force applied. Is it now any better than 2,000 lbs. would be at its original position, and again has not a crankmore power, going from the center to the point of half stroke, than it has going from the half stroke to the opposite center ? I consider eight twenty-fourths of the entire circle of the crank of very little value; three twenty-fourths going to thecenterand one twenty-fourth from it; this makes one-third very little power one-third medium, and one-third most energetic. You saw fit to publish my first communication, and criticised it most severely. Why not publish this dne and give me a chance to lie heard ? In due time I expect to call at your office with my engine, and I anticipate no difficulty in convincing you that the favorable notice which you have promised is richly my due. J. W. H. Dpcorah, Iowa. [Wv urc ready to be convinced, and sincerely hope our COT-respondent may succeed in his attempt.—EDS. Is the Yearly Number of Earthquakes Increasing ? MrK;=T.3. EDITORS :—I have inquired of the Tribune if earthquake were increasing, and how many such phenomena did occur during the past two years. It is mum. The same inquiry put to the Evening Post brings out an indefinite and unsatisfactory reply. You said in your January number that 1888 would be remembered as the earthquake year. So says the Boston Traveler, etc. Now MM. Perry and Ansted record 3,240 earthquakes in fifty years, from 1800 to 18S0, which is on the average nearly sixty-five each year. At this annual ratio some over 1,000 must have occurred in the sixteen years from 1850 to 1866. As over 7,000 are tabulated previous to 1850, the number down to 1866 must be considerably over 8,000. I now inquire how many earthquakes occurred in 1867? How many in 1868 ? What is counted as aa earthquake, the whole number of shocks including the first principal shock, or is each distinct shock recorded as one earthquake ? Nineteen shocks oecuredin California—were these nineteen earthquakes or one earthquake ? Is there no record of the number occul-ring in America since its discovery and settlement ? Is there no beam of information in the United States on this subject? P.v. :. E. Merriam, when living, kept a yearly record of these mundane convulsions: is there any kept since his death? My meager records give over thirty-five hundred shocks as occurring during the years 1867 and 1868. Are earthquakes increasing or not ? What says the scientist ? Light is wanted by D. T. T-----E. Houses Point, N. Y. [No very definite and reliable data as to the exact number of earthquakes which annually occur can well be obtained. Any slight convulsion of the earths surface must be counted as an earthquake, but when a rapid succession of these occur, TO believe they axe counted as one. The reason why 186S v 1 b? remembered as the Earthquake Year is because the ):ivu1sions were so general, violent, and disastrous, rather 1ao number which took place, which may or may not have :.?cn ::. er thanduring many previous years not particularly not o-.l for earthquakes.—EDS. --------- Good Remedy for Seasickness MHSSILS. EDITORS :—In your number of Nov. 25, 1868, are BiVen rules by which seasickness may be avoided, which you credit to the Medical Gazette. If I had to go through the programme laid down in that article I think Id stay at home, as the pleasure of a sea voyage would be materially diminished. Ive boon a traveler for twenty years, by sea when necessary, and always more or less seasick the first day or two out, with th c exception of one voyage. A day or two before leaving Paris, in Dec. 1867, a friend asked me if I was subject to seasickness. I answered, Yes, a little. Well, said he, try my remedy for it. It may prevent it entirely, and is at least worth trying. He handed me a dozen little pills of the homeopathic persuasion. and said, Here are two doses, take one dose when you get under way at sea and/if nausea comes on, take the second. If the two doses dont stop it there T,.J1 be no use in taking more. I stuck the little paper of pills in my vest pocket and came over to England and spent the Christmas holidays at an English home. If you ever spent Christmas in England, you know that the second rule laid down by the Medical Gazette, namely, to eat a hearty meal before going aboard, has to be practiced pretty often during Christmas week. I thought myself in fine condition to be very seasick and expected to pay old Neptune dearly for the good things taken at my friends table. I sailed from Liverpool on the 29th Dec, and when fairly in the channel took my first dose of little pills. The wind was fresh and New Years morning dawned with as terrific a gale as ever swept the Atlantic. Another met us on the 6th of Jan. 1868. Every passenger on board but myself was more or less sick. I escaped entirely through both storms, and if the little pills were not the cause I am at a loss what to ascribe it to. They were sugar of milk medicated with petroleum—nothing more. If voyagers try the Gazettes seven rules and they fail, I would advise a trial of the little pills next time, for it will take all one voyage to go through the rules. Yellville, Ark. E.-A. PHILLIPS. ------------------------—— The Blue Color of the Skies MESSRS. EDITORS :—Rays of light, however brilliant they may be, are invisible when they pass through a dark room, or any other dark place, unless they are arrested, held, and refracted by some substantial thing. Now, the space intervening between the earth and the sun, and all other spheres, is an absolute,void, excepting the distance reached by the earths atmosphere. Through this immense space, and through all space not occupied by matter, the sun penetrates with its bright rays; yet, utter darkness—intense blackness— occupies and prevails in all this void, because there is no matter or thing therein to arrest, hold, and refract rays of light. Were it possible that one could be placed at a point midway between the earth and the sun, nothing could be seen other than spark-like spheres bedecking a black firmament in all directions. All these,even the sun, would appear only as bright balls of light, with or without radiation, just as light appears to the mariner through the darkness of night. The appearance of this darkness—this blackness, is modified to our sight here by the halo caused by refracted light from objects immediately surrounding us on the surface of the earth and from vapors in the earths atmosphere; andit is this modified blackness which causes the apparent blue color of the skies. RICHARD A. WHITMOKE. Poisonous Odors L Union Medicale is very positive on the subject of the deleterious action exercised by the perfume of flowers, especially such as lilac, jessamine, hyacinth, tuberose, on persons who have the imprudence to leave them at night in the bed-chamber. The more or less fictitious cases of suicide and assasina-tion, which have been related under this head, should not induce us to doubt the reality of the asphyxiating power possessed by strongly smelling flowers. Certain odoriferous fruits share the same deleterious property. We read in the Union Bourguignon of Dyon, that a grocer who had slept in a small rooom, in which the contents of three chests of oranges had been piled up, was found asphyxiated in the morning, and was only resuscitated by the most energetic treatment. Our readers will also recollect a case not long since reported of death resulting from the odor of quinces, which occurred from sleeping in a room where a large quantity of them were kept. Extinguishing Kerosene Limps, MESSRS. EDITORS :—I see in answer to correspondents, No 8, present Vol. you advise your readers that to extinguish a kerosene lamp safely, turn the wick down until the flame is low and blow under the glass. You will find it requires pretty strong blowing and some practice, in order to do it quickly. Permit me to submit the following which is free from danger, and isinstantaneous: Turn the wick up so as to produce a large flame, but not high enough to smoke; then blow squarely across (not down) the top of the chimney. In explanation : A strong current of air across the top of the chimney produces a corresponding current up through the chimney; the latter current lifts the flame off from the wick and instantly extinguishes it. Atlanta, Ga. J. C. DODGE. --------------.o Power Required is as the Square of Velocity. MESSRS. EDITORS:—T. W. Bakewell, on page 119, current Vol., says it would require eight times the steam to propel a boat f jom New York to Liverpool in five days that it would if 10 days were occupied, in the preceding sentence, however, he says, it would require only four times the coal or steam. These two statements are so diametrically opposed, that however plain the solution may be to him, it is difficult for any reader to ascertain his real meaning. He admits that resistance for any given distance increases as the square, and of course four times is correct. The source of his error is that while he counts double the velocity of piston and wheel, he omits the important item of the time occupied, being only one-half, which he would not have done had he been a more accurate MATHEMATICIAN. --------------------------------- The Hydrogen Gas Theory. MESSES. EDITORS :—Under heading The Hydrogen Gas Theory, on page 86, current volume of SCIENTIFIC AMEKICAN, you take issue with the views expressed by your correspondent (W. H. L.), and your principal ground or argument for so doing is that hydrogen gas is not explosive or in other words, cannot be ignited without the presence of oxygen. So far I believe you are entirely right for combustion is nothing- more than the chemical combination of two or more substance8-and cannot take place independently of atmospheric air, oxy gen gas, or any of the other bodies usually called supporters of combustion. But, admitting that there can be hydrogen I gas in steam boilers at any time, there must be also oxygen gas,f orthe hydrogen gasmust necessarily have been generated from the water or steam, and its equivalent of oxygen must have been created at the same time, for it is well known that i water cannot be decomposed and one of its component gases pxtracted from it, as it were, without at the same time liberating or generating its equivalent of the other gas, that is, for every pajt (in weight) of hydrogen gas generated, there must also be generated eight parts of oxygen or vice versa. The theory advocated by your correspondent—the explosion of boilers by the presence of hydrogen g-ns—does not seem at all improbable to me, and this I say with due deference to your opinion. My reasons are these : Electricity is manifested during changes of state in bodies, such as evaporation, condensation, etc. There must be, then, more or less electricity evolved by the generation of steam in the boiler. Electricity, on the other hand, has the power, is in tact, one of the most powerful means under known circumstances of decomposing water; it does not, therefore, seem unreasonable to suppose such conditions may exist in the case of a boiler with a heavy head of steam on, perhaps very little water in, and an intensely hot fire under, and that a large quantity of electricity may be evolved, and a certain quantity of water or steam thereby decomposed. If this should be the case (and it might probably be experimentally ascertained) the smallest leak in one of the flues or in the boiler itself, might cause the oxygen or hydrogen gases to be ignited, and the necessary consequence would be a terrific explosion. The above views, although, presented in a crude manner, may perhaps account for those extraordinary cases of boiler explosion, which to the present time have remained, as far us I know, without satisfactory explanation. St. Louis, Mo. R. DESEONNE. xac Product of a dial-coal Furnace. MESSKS. EDITORS :—It may be a matter of interest to your readers to know what can be done, or, more properly, what has been doneby a charcoal furnace. Our furnace, at this place, a hot-blast charcoal furnace, meaures 40 feet in height and 9-J feet in the bosh. During-the month of January last, it made 784 tuns of pig-iron, of 2,268 lbs. to the tuns. This, I believe, is about 25 per cent more than any other charcoal furnace has ever produced in the same length of time. If I am in error in regard to the comparative amount, I hope to be corrected and informed of the name of the furnace and the date of manufacture. This result has been attained without in any way forcing the furnace and on 106 bushels of coal to the tun of iron produced. EDWIN HABRISON. Irondale, Mo. What is tlie Reason? MESSRS. EDITORS :—What is the reason that a 3i or 4-incli crank pin is strong enough for an outside connected engine, while an inside connected one requires a six-inch pin, and often breaks them of that size ? Who knows ? EGBERT P. WATSON. New York city. A Report on Ordnance. The report of the Joint Committee on Ordnance, made in the Senate by Mr. Howard, condemns both the Rodman system of gun making, adopted in the army, and the Dahlgren system, which is used in the navy. These systems, the report says, while partially successful with smooth bores, have uniformly failed as rifles. Several of the Rodman guns have burst spontaneously while being finished in the foundcries. The Committee recommend that no more of them be purchased, but that experiments be made to determine upon some more reliable system of fabrication. Tlie failure to secure better gun s heretof ore,the Committee attribute to the fact that officials have been gun inventors and have secured by their influence the adoption of their inventions without regard to merit. The report is accompanied by a bill which places all experiments and the selection of arms for both army and navy in the hands of an Ordnance Commission, to be composed of three army and two navy officers, and two civilians eminent for their attainments on the snbject. The bill abolishes the Ordnance Department of the army by merging it in the artillery. This report assumes unusual importance in view of the fact that the Ordnance Department has asked for appropriations to purchase over 1,900 heavy guns made on the Rodman plan, for armament of the fortifications. VALUE OF PATENTS IN ENGLAND.—An English circular states that an American patentee of a device for dressing millstones by a revolving diamond, has realized over one million dollars; and the estimated value of the patent for the next ten years is put down at five millions. This statement is put forth by a patent agency in London for the purpose of exciting English business, and may therefore be accepted with some grains of allowance, but we do not doubt that there are many American inventions that would pay well in England and Prance if properly managed. IT is announced that thetrains on the Central Pacific Bail-road have been delayed in the Sierra Nevada mountains ty one of the most terrific snow storms known in that region. The snow belt extended over eighty miles; the usual distance is about fifty. The snow-sheds withstood the storm, v. Uei? completed, and furnished full protection to the road. 152 Improved Device for Converting a Wheeled Vehicle into a Sleigh. It is not uncommon to see a sled attachment to wheeled vehicles suspended to the axletrea and held from turning by means of a strap or chain-lock; but as in this case the resistance to transverse motion must be borne entirely by the axle, which is only a single point, the strain is too great at this single point. The engraving gives a view of a plan that seems to avoid; this objectionable feature. It consists simply of a shoe attached to each wheel by means of spring straps held to the felloes of the rim by ordinaryclips,and secured at their centers by a plate embracing one spoke, secured by bolts or screws to the projections of the shoe, which lap on each Bide of the wheel rim. For purposes of appearance and additional security from turning, spring braces,as seen on the hind wheels, may be added, although, if the shoes are made long enough, there can be no danger of their turning, or of the wheel revolving. It will be plainly seen that the strain is divided by being placed on the rimrather than the axle of the -wheel. The device can be readily attached or detached as may be desired, and when detached is so compact and portable that it can be carried in the boot, or under the seat of the vehicle, to he ready for use when needed. This device was patented through the Scientific American Patent Agency, December 29, 1868, by Joseph Stonebanks, who may be addressed at College Point, Queens county, N. Y. Improvement in Portable Fences, For herding cattle and other stock, and for other purposes, a temporary and movable fence is a great desideratum; one that can be easily placed in position and taken down,light,strong,and portable. Such is that shown in the accompanying engraving. It may be made, as represented, of horizontal strips, or in the form of a picket fence, as desired; in the latter case, the stringers being mortised,or cut, as are the first and third bars in the horizontal strip fence. The posts are uprights, of board or plank, recessed at the top and at a point to receive one of the lower bars, and nailed or screwed to a horizontal piece resting on the ground. The bars of the fence sections are mortised or halved,and fit into the corresponding recesses of the posts, as plainly seen in the engraving. They are firmly held by means of simple buttons secured to the bars, one to each section. The sections may be set either in straight lines or at angles of any grade, as required, to inclose a plot of ground rectangular, or of any form approaching a circle. The portability and the ease of management of this fence is quite obvious, Patented through the Scientific American Patent Agency, Dec. 29, 1868. Communications should be addressed to Coolidge & Rollins, Jersey Mills, Pa. Discoveries In tlie Nortli Sea, The results of the dredging expedition recently made by Dr. Carpenter and Professor Wyville Thomson in the North Sea are very interesting. In the first place they discovered that at 200 fathoms,at least, animal life exists. At nearly a mile deep it is abundant; at that depth animals are as well developed as at the surface, beside they are not confined to the lower groups; the whole of the invertebr are well represented. They also found that the temperature is not dependent on depth; even in places I quite contiguous to each other the temperature was not uniform. In the deep waters between the Faroe and Shetland Isles, and to the westward, they find a formation being deposited which is exceedingly like chalk, and contains similar or identical fossils. The fauna differed somewhat with the temperature. The bottom of the sea to the westward of the islands named consisted of ooze, or shining mud, of the consistency of thick treacle, of a pale grey colour; this was full of sponges of the most extraordinary kinds, and of very singular forms. During six weeks the explorers only got five days of good weather.
This article was originally published with the title "Correspondence"