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that the different colours exhibited by A new Theory of Ligît and COLOURS.

very thin glass plates, or by soap-bubbles, VERY one knows, that proceed from the vibratory motion excita the famous Sir Isaac ed by the rays of light in those plates or Newton explained the bubbles, which must be thin to a certain

phenomena of light and degree, in order to be susceptible of these E

colours by supposing, vibrations, and these vibrations being that the rays of light A again communicated by them to the ether, themselves were of dif in proportion to the different degrees of

1erent colours, some of thickness in the parts of the plate or bubwhich are generally reflected from any ble, produce in us the different sensations object more copiously than any of the which we call red, green, blue, &c. reit; and that the object always appears

Mr. Euler confirms this hypothefis by to be of the colour of those rays which are several other experiments ; and it is like. most copiously reflected from it, except wife in part adopted by M. l'Abbé Nollet, the colour of white, which is communi famous at Paris for his lectures on expe. cated by an object from whence all the B rimental philosophy ; for by many expe. different sorts of rays are equally reflect

riments he has endeavoured to prove, ed, and the colour of black, which is that light is a most subtil Auid by which communicated by an object from whence all bodies are pervaded, as well as sur. no rays at all are reflected to the eye. rounded, and which becomes sensible to

But Mr. Euler of the royal academy at us by being put in motion by infiamed Berlin, upon confidering the effect pro. bodies or otherwise ; but then he embraces duced by looking glailes, concluded, that Sir Isaac Newton's opinion as to the rays the rays of ligle reflected from any fur- C of light being of different colours, and face ought to make us see the luminous producing in us the idea of that colour body from whence those rays originally which is most copiously reflected from any proceeded, and not the surface itself, object. therefore he supposes, that light is not produced by a continual emanation of A curious Remark upon the Nature and Prorays of light from the sun, by which lie duction of those Injects called BritLES. would at lait be quite exhausted ; but that it proceeds from a certain fortur I Tohaving been often observed that, if at

certain feasons of the year, a mole, or

D vibration communicated by him to what other small animal, be killed, and left we call the ether, much after the same above ground, the body disappears in a manner as the quiverings of a bell gives very few days, more or less according to to the air a motion resembling its own, the reason of the year, and the nature of and thereby communicates to us by the the ground. This phenomenon excited ear the idea of sound. According to this the curiofity of Mr. Gleditsch, of the hypothesis, a greater or lesser rapidity in royal academy of sciences at Berlin, to the motions of the ether will produce endeavour to find out the cause of this more or fewer vibrations in our organ of sudden and extraordinary disappearance. light, and hy that means the ideas of dif- E For this purpose, in the month of May, ferent colours ; as the difference between he killed a mole, and left it above ground a hollow or Trill round proceeds from the in his garden, where there was a sost, different rapidity of the vibrations of the black, and moist earth. In two days the air.

body as usual disappeared, but a littie From hence this gentleman concludes, spot of earth near the place appearing to Qctober, 1755.

Mmm 2

have

Oct.

460 Of the Perspiration of VEGETABLES, have been frih turned up, a (carch was in the day-time. 3. That in the daymade, and the body of the mole was cime they perspire more in the sun than there found buried at least a hand's breadth in the shace, even tho' the latter be the under the earth : The next day this grave warmeit situation. From hence perhaps was found to have been made half as deep arises the rapid growth of vegetables unagain, and four beetles were found under der bell-zlailes ; for the rays of the sun the body, who for this reason were rur being much intercepted by the bell, the pected to have been the grave.diggers. A perspiration is thereby diminished.' For in order to dilcover for what purpose these the same reason, without doubt, those creatures undertook such a laborious em. fruits which are not too much exposed to ployment, the body was again covered the rays of the sun, grow to be the big, with earth, and left there for fix days, gest, and so likewise those paper bags when it was again uncovered, and then which he bunches of grapes are put into, it was found, that there were three or not only protect them from birds and flies, fourscore of little whitith worms sticking but also increase their beauty. By this all round it; from whence it was con we may perceive the use of the leaves, fluded, that these were the progeny of B which is to be a made for the fruit; and the beetles, who, being left there hy their we may likewise see the reason why dark parents, were to find their nourishment and cloudy weather is best for the fruit from this dead carcass until they arrived after it begins to ripen, because such weaat a state of maturity. To confirm this ther diminishes ihe perfpiration, and corije quie, Mr. Gleditsch afterwards le thereby increases the bulk of the fruit. the bodies of frogs, small birds, files, There are we find some trees which lore &c. upon the same, or such like ground, their leaves much rooner than others of and not only found that they were all de- the same kind, tho' both growing the cenily interred, but often saw the beetles fame sort of ground; the reason of which at work in digging their graves and buryo certainly is, because the former happen to ing them, by which means they make a be by their situation more exposed to the plentiful provision for the support of their sun, which makes them perspire more (amilies. But we hope none of our witty abundantly The 4th observation was, gentlemen will from hence take occasion that perspiration proceeds chiefly from the to call a certain worshipful company, a leaves. The sth, that the superior sur, company of blind beetles,

face the leaves, being more exposed to D

the sun, is thereby made to perípire more Several curious Observations upon the Per

than the inferior. The 6th, that those SDITATION of Trees and ciber Vege

vegetables which have thick leaves, and tables.

fruit of a juicy substance, perspire the ONI E years since Mr. Guettard laid

and the crore do rot fand much in before the royal accademy is sciences need of being watered. The 7th, that & Paris, an account of a great nua.ber perípiration grows much less towards the of experiments he had made, for disco. winier than it is in the summer. And vering the perspiration of trees and other E the 8th, that the liquors produced by vegetables, from whence he deduced the perspiration, from vegetables of quite Soilowing observations. If. That all ve different kinds, are nevertheless perfectly getables perspire more than could without the same, having all the same intipidity, experiment be believed.

For a small and no way differing from common water brarch of a cornel tice, whichi wcighed in clearness, taste, sinell, or weight, only five drams and an hell, apothecary's Mr. Guettard made these experiments weighi, kept under an experiment ior 14 by means of a glass-bail or bottle of a days, in the month of August, produced

F

foot diameter, which, beside a neck in by perspiration in that sime, 20 ounces, the víuai form, had two arms or necks Four drams and an halt, which comes to opposite to each other, and placed at the one ounce, three drams, and three quar two extremities of the diameter, perpen. Rers of a dram per day, one day with dicular to the line of the neck ; being a ano her, that is to say, it perspired daily vesci of that fort which by chymists is more than double its own weight; but few called Glauber's recipient. The branch other vegetables perfpire so plentifully in of the tree or vegetable was introduced proportion, tho' most of them perspire thro' the reck of this glass-ball, and one daily as much as they weigh ; from G of the arms being set upright, was well wiience we inay judge what an enormous corked, whilst the other was made to enquantity of water must be daily exhaled ter into a bottle which was buried in the irem a large forest,

2. That all vegeta earth quite up to the neck, and closely bles perspire muah less in the night than luted,

leait ;

Thc

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1755. LIST of the French Navy, The same gentleman has lately commu

Names. nicated an account of several new experi Le Temeraire ments he has made, from whence he has L'Herissant deduced the following observations, it, Le Redoutable That the perspiration of vegetables in L'Entreprenant creases or decreases exa&ly in proportion La Guerre as the heat of the run increafes or de. L'Heros creases. 2. That their perspiration does A Le Palmier not increase in proportion to the quantity Le Couragieux of rain upon the ground : On the con. Le Prudent trary, when the sun begins to thine after Le Defenseur a heavy rain, the perfpiration of vegeta L'Hector bies is never the first day at the greatest Le Ferme height. 3. That the leaves do not draw L'Esperance so much moisture from the air as one

Le Juste would be apt to believe ; for an orange

Le Saint Esprit tree inclored in a glass' globe perspired B Le Dauphin Roial daily near to the weight of all its leaves, Le Nortumberland and did not seem to suffer in the least by Le Superbe its imprisonment. 4. That in the shade Le Fleurissant the perspiration diminishes in proportion Le Lys, taken to the deepness of the shade. From hence Le Content it is that vegetables grow white in a cel. L'Eveillé lar; for as they do not there perspire, L'Inflexible their vesicles are made to well by that с

L'Hazard water which is confined in them, and by L'Illuftre this means they acquire a double advan Le Leopard tage, that of becoming more white, and L'Actiff that of becoming more delicate. 5. That L'Opiniatre the branches perspire less than the leaves. L'Hardy 6. That the fowers perspire likewise less Le Capricieux than the leaves, in the proportion of s

Le Content to s. 7. That the fruit perspire Nill Le Triton less, especially those that are of a juicy

D L'Achille kind. 8. That the evergreens perfpire

Le Protee almost nothing in the winter, in compa

L'Hercule rison with what they do in the summer, L'Orpheus and their perspiration is at all times less Le Glorieux than that of any other trees. To con. Le Lion clude, what is worth the attention of all Le Vainqueur Botanilts who incline to repeat or to push Le Magnanime these experiments, is, that the greater or E Le Phenix lesser transparency of the glass veel they Le St. Philip make use of for their experiments, may

Le Bienfaisant occafion a very considerable difference. Le Sphinx

La Medee A List of the FRENCH Navy, 1755.

Le Vaillant

Le Dragon
Names.

Guns. Men.

Le St. Michel
Second Rates,

Le Boree
A Formidable

80 800

F

L'Ecumant 80

700 Le Solide La Corone

80 700

Le Sage Le Soleil Roial

80

700 L'Ecole Le Duc de Bourgojne 80

700 L'Elizabet L'Ocean

80

700 Le Toulouse Le Tonant

So

700 L'Aurora Third Rates.

Le St. Louis L'Alcide, taken

74 580 G Le Brillant L'Intrepid

74

600 Le Griffon La Sceptre

74

600 Le Corbillon Le Conquerant

74

600 Le Parfait Le Magnifique

74

600 L'Argonaute

580 580 580 580 580 580 580 580 580 580 580

64

64 64 64 64 64

580

64 64 64 64 64 64 64

580 580 580 980 580 580 580 $80 580 580 580 580 580 580

64 64 64 64

64 64

L Le Foudroyant

64
64
64
64
64
64
64
64

580 580 580 580 580 580 580 580 580 580 580 580

64

60 60 60 60 60 60 60

400
400
400

400
Rates.

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462 Ministers Abroad; American Governors. Oct, Rates. No of No o No of Fort of Annapolis, Lieut. Col. Robert Ships.

Guns, Men, Monckton, Gov. 21 of 8o guns

560

5000 Newfoundland, Capt. Francis William 30 of 74

16

1184 9600 Drake, a captain in the navy, Gov. 3d of 70

8

560 4800 New York, Sir Charles Hardy, Kot. 3d of 64

2304

20880 a captain in the navy, Gov. 3d of 60

7
420 3340 New Jersey, Jonathan Belcher, Esq;

А

formerly governor of New England, Gov. Total 74 5028

43620 Pensylvania, , Robert Hunter Morris,

Esq; Lieut. Gov. N. B. We have not yet been able to Maryland, Horatio Sharpe, Esq; Lieut. precure an exa& lift of their frigates, &c.

Gov.

Virginia, Robert Dynwiddie, Eras Tbe following Lists will, also, at this Time be

Lieut, Gov. agreeable to cur Readers.

North-Carolina, Arthur Dobbs, Erqi His Majesty's MINISTERS Abroad. Gov. Southern Province.

B

South Carolina, James Glen, Esq; till N Spain, Sir Benjamin Keene, knight the arrival of William Lyttelton, Esqi

Gov. and plenipotentiary.

Georgia, John Reynolds, Ery; Gov. Portugal, Abraham Castres, Esq; en

West Indies. voy extraordinary.

Jamaica, Charles Knowles, Esq; vice. Naples, Sir James Gray, Bart, envoy admiral of the blue, Gov. extraordinary.

Barbadoes, Hon. Grenville, Ela; Sardinia, Rt. Hon. the earl of Roch. C brother to earl Tempie, Gov. ford, envoy extraordinary and plenipo Leeward - Inands, George Thomas, Erg; tentiary.

lately governor of Pensylvania, Capt. Gin. Turkey, James Porter, Esq; F. R. S. St. Christopher's, Richard Coupe, Esq; ambassador,

Lieut. Gov. Tuscany, Horatio Mann, Esq; envoy Antigua and Montserrat, Rt. Hon, lord and refident.

Hawley, Lieut, Gov. Swifferland, Arthur Villettes, Esq; mi Bermudas, William Popple, Esq; Gov. nifter.

Bahama-idlands, John Tinker, Ergi Venice, John Murray, Efq; resident. D Gov.

Northern Province.
Vienna, Robert Keith, Esq; minifter

Commissioners of Trade and Plantations. plenipotentiary. Denmark, Walter Titley, Esq; envoy

T. Hon. earl of Hallifax, John Pitt, R

Hon. James Grenville, Andrew extraordinary.

Stone, Francis Fane, James Oswald, Saxony, 7 Sir Charles Hanbury Willia Hon. Richard Edgecumbe and Thomas

Rufia, Sams, knight of the Bath, en. Pelham, Esqrs. voy extraordinary.

E Holland, Hon. Col. Yorke, minister

QUESTION I. plenipotentiary. Hamburgh, Bremen and Lubeck, James

HERE is a triangle whose fides are ΤΗ

given, viz. 300, 376 and 484. And Cope, Esq; resident.

if, from a point within the same triangle, Liege, George Creslener, Esq; resident,

lines be drawn to the angular points of [recalled)

the triangle, the angles formed round that Brussels, Solomon D'Ayrolle, Esq; re.

point will be 104, 112 and 144 degrees. adent.

Required the distance from the same point States of the anterior Circle of the Em. F to each angle of the triangle. pire, Onslow Burrish, Esq; minifter.

Dogmersfield, Hants,

J. BUIL. A List of the Governors and Lieutenant. Governors of our several COLONIES in

QUESTION II. AMERICA,

HERE is a quadrant whore radius North-America, ASSACHUSETS Bay, the Hon. circle. And suppose at either corner ano

G

ther circie be inscribed, so as to touch the New Hampshire, Benning Wentworth, radius, concave arch of the quadrant, and Esq; Gov.

convex arch of the other circle. Required Rhode-10and.

the diameter of both circles. J. B. Connecticut.

N. B. This question was once proposed, Nova Scotia, Col. Charles Lawrence, but has not been truly answered. Lieut. Gov,

5

o&t. I, 1755.

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1755. Utility and Advantage of BROAD WHEELS:

463

there be a perfectly level and smooth piece Our Readers will not be displeased to see some of pavement. Then let the said carriage

Account of a Pampblet, called The Utility be on the green at some distance from the and Advantages of Broad High Wheel

pavement, and let a man take hold of the Carriages demonstrated, by Moses Wick inafts and draw the carriage after him ham, of Hatfield, in Hertfordshire.

over the green to the pavement ; he will He author

easily perceive, that as soon as the wheels

T Pain unteeriod of demonftration, en: A are upon the pavement, that the carriage

deavoured to obviate the objection, " that will move forward with much less force, broad wheels go heavier against hill than than when it moved on the green ; for narrow ones," makes it next appear, which there can be no assignable cause por. “ that the advantages in the use of broad fible, than what I have already alsigned. wheels on any fort of surface whatsoever, Now if the difference is so much, as to are more than enough to counterbalance be perceptible in the last mentioned care, all the inconveniences that polfibly can where (perhaps) you cannot see any man. arise from the use of them.” He goes on: ner of impreilion the chaise has made on

« First, common sense tells us, that B the green : I leave any one to judge what narrow wheels must cut into, or make a that difference must be, where the ima greater impression on any surface, than pression is perhaps 20, or 100 times as broad ones can. I imagine the difference much. I do not speak this by way of must be more than the difference between begging the question, having been myself the breadth of the narrow wheels and well satisfied of the same by experience." broad ones ; (wlich for want of a proper He afterwards attempts to prove, that apparatus I cannot rightly determine) but the size of our wheels, in general, are were it only that, the impression would c not such as are most advantageous; and be but one third of that which the nar. that the larger the wheels of any carriage row ones would make.

are, the less force is required to move, or Now by giving the obje&or, all the ad keep in motion such a carriage. He goes vantage in the dispute he possibly can have, on then to demonstrate the excellency and (for the softer the surface is, the more utility of broad wheels, and says, have the broad wheels the advantage of “ In short, so many are the advantages the narrow ones) we will suppose the that would accrue to every person who road so hard that the narrow ones cut in makes use of wheel-carriages, that I but one tenth of an inch (which confider- D make not the leait doubt, ohut if they ing the earth's elasticity, I question whe once get into the use of broad high wheels, ther it can be the case any where, rocks they would find them come so easy after excepted) then the broad wheels will cut the horses, that were the world as superin but one third of that tenth.

ftitious and idolatrous as it was some cenThe tenth of an inch may seem (per turies past, they would be apt to deify the haps) to those who do not seriously think person who first persuaded them into the about things, to be so inconsiderable, that use of them I no more doubt but that the difference between that, and one E three horses, take fields, roads, and seathird thereof, is not worth our notice; but sons in general, would be able to fetch they should consider, that tho' it is but a more corn, hay, &c. with such a carriage tenth of an inch, yet it makes a consider from the field, than four horses could do able angle with the horizon,

in the same time with our present narrow For tho' the wheels of carriages seem to wheels, than I doubt whether three men touch the ground for near the length of a could drive any affigned quantity of rubfoot, and where the surface is not so hard, bilh, &c. over a soft meadow half a mile much more ; yet, in truth, a true circle wide, with our common wheel barrows, on a true horizontal plane, suppose it im. F in less time than four men could drive the penetrable, would touch that plane but in same quantity away with the same fort of one minute point ; then if we suppose a wheel-barrows, only they should have substance placed before such a wheel wheels to them so narrow and tharp, as equally hard, which is to suppose what is to be like the wheels of the ploughs with the real fact, we shall then sind, that the which we plow our land. constant riling before the wheel, will make Our bye-roads (weresuch carriages used) a considerable angle with the horizon ; being once made fit for the reception of which is every moment to be surmounted. G them, would be as much better than they

Toillustrate more fully what I have been are now, as the great roads are now beta observing, and to make it obvious to the ter than the bye-lanes. How common is meanest capacity, let us suppose, a chaise, it to see our bye-lanes and roads for the or any other light carriage, which a man most part, with such decp ruts and holes, is able to pull after him, and let us rup as to be almost impátfable; nay, many of pose it to be on a smooth, well mow'd them in the winter are absolutely so." bowling-green ; at the Gde of which let

The

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