Philosophical transactions, Vol. L. Part I. For the year 1757. · Various
SIRS,
ON the 20th of March 1755, we presented an address to this illustrious Body, intituled, “An Attempt to point out, in a concise manner, the Advantages which would accrue from a periodic Review of the Variation of the Magnetic Needle, throughout the known World; requesting contributions thereto, by communicating such observations concerning it, as had then been lately made, or could be procured from correspondents in foreign parts.” This address was read at the same time, and afterwards honoured with a place in the Transactions, vol. xlviii. part ii. for 1754: which favour we now acknowledge in the most grateful manner; and, pursuant to our engagements, beg leave to lay before you some account of the communications received, with a specimen of the uses and applications which we have been enabled to make of those, and other assistances with which we have been indulged. On application to the Honourable the Commissioners of the Navy, we were obliged with an order of free access to all their masters log-books and journals. The Directors of the Honourable East India Company granted the like privilege. The Honourable Committee of the Hudson’s Bay Company obliged us with sundry observations, made, and tabulated, by their own Captains. James Bradley, D. D. Regius Professor of Astronomy, and F.R.S. favoured us with several observations made at the Royal Observatory at Greenwich.
John Hyde, Esq; F.R.S. communicated a sett of useful observations, extracted from two journals kept on board the Triton and Britannia East Indiamen. A correct journal kept on board the Delawar East Indiaman was handed to us by a gentleman unknown. Capt. George Snow furnished a considerable number of observations, made with care and accuracy by himself, in several successive voyages to, and from Barbadoes and Virginia; together with several remarks upon the subject: _One_, which we apprehend to be material, we beg leave to insert, as it meets with some confirmation by the tables annexed; _viz._ “At Barbadoes the variation seems at a stand very near; for in the road, 1752, I observed 5 degrees east; and by Mr. Halley’s draught, in the year 1701, 5½ degrees: in 1747, at Port Royal keys, Jamaica, I observed the variation 7° 20’ E.; and on the coast of Carthagena the same week, off the high land of Sancta Martha, 7° 45’ E. nearly south of Port Royal: Therefore these curves are not much altered; and the curve at Jamaica is nearly at a stand, as tho’ tied; and the south part of them, with the rest, dropping to the westward.” Mr. Mungo Murray, author of a treatise on ship-building, presented us with several observations taken on board the Prince Edward and Chesterfield East Indiamen, and his Majesty’s ship the Neptune.
For all these favours we return our sincere thanks. No observations made upon land have been received, except Dr. Bradley’s aforesaid; which has frustrated our intentions of continuing the curves from sea to sea. By collecting, comparing, and adjusting, all these materials, we have been enabled to construct variation-curves upon Dr. Halley’s mercator-chart, adapted to the year 1756; which will soon be in readiness to present to this Royal Society. As a work of this kind requires much time, and a multitude of observations, both by sea and land, to render it more perfect and general; we hope the ingenious in all nations will lend their assistance: By this means every periodic review will be productive of improvement. From the first instant that we made this affair the object of our more particular consideration, we have attended to the mode of increase and decrease in the variation: and as a considerable number of observations, made at periodic times, and duly registered, seem to be the most essential toward determining the laws of its mutation, or proving its irregularity, we have therefore formed a sett of tables, from actual observations collected for the years 1710, 1720, 1730, and 1744, the date of our last chart; which, together with Dr. Halley’s for the year 1700, and the present chart now publishing, compleat six reviews: These are tabulated, and shew the quantity of the variation, at those several periods, to every 5 degrees of latitude and longitude in the more frequented oceans; which we hope will prove acceptable, as nothing of the like kind has yet appeared, or can easily be obtained.
Our materials have been so deficient, that even in the limits to which our tables are confined, we have been obliged to leave blanks in some of the above periods, for want of that concurrent testimony, on which the numbers inserted are founded: but, considering the difficulties unavoidably attending a work of this sort, and the little assistance which we have met with from private hands, we hope that this Royal Society will not only excuse those vacancies, but also those in the great tracts of sea, as well as land, concerning which we are very unwillingly obliged to be intirely silent. Agreeable to our former address, we lay only what appear to be facts before you, without attempting to introduce any hypothesis for the solution of these phænomena; some of which (being very extraordinary) we recommend peculiarly to the notice of those gentlemen, who may endeavour the investigation of their causes. Under the equator, in longitude 40° E. from London, the highest variation during the whole 56 years appears to be 17°¼ W. and the least 16°½ W.: and in latitude 15° N. longitude 60° W. from London, the variation has been constantly 5° E. but in other places the case has been widely different; for in the latitude 10° S. longitude 60° E. from London, the variation has decreased from 17° W. to 7°¼ W., and in latitude 10° S. longitude 5° W. from London, it has increased from 2°¼ W. to 12°¾ W.; and in latitude 15° N. longitude 20° W. it has increased from 1° W. to 9° W.
But there is still a more extraordinary appearance in the Indian seas: for instance, under the equator, Longitude from| Variation in _London_ | 1700. | 1756. --------------+----------+--------- Degrees. | Degrees. | Degrees. 40 E | 16¾ W | 16¾ W 45 E | 17¾ W | 14½ W 50 E | 17½ W | 11¾ W 55 E | 16½ W | 8¾ W 60 E | 15¼ W | 6 W 65 E | 13½ W | 4½ W 70 E | 11½ W | 2¾ W 75 E | 9¾ W | 1 W 80 E | 7¾ W | 0¼ E 85 E | 5½ W | 1¼ E 90 E | 4¼ W | 1 E 95 E | 3¼ W | 0½ W 100 E | 2½ W | 1 W --------------+----------+--------- Where the west variation in the longitude 40° E. is the same in both the above years; and in 1700 the west variation seemed to be regularly decreasing from longitude 50° E. to the longitude 100° E.; but in 1756 we find the west variation decreasing so fast, that we have east variation in the longitude 80°, 85°, and 90° E; and yet, in the longitude 95° and 100° E. we have west variation again. Such are the irregularities, that experience hath shewn us, in the variation of the magnetic needle; which appear so considerable, that we cannot think it wholly under the direction of one general and uniform law; but rather conclude, with the learned and judicious Dr. Gowen Knight, Fellow of this Society, in the 87th prop. of his treatise upon attraction and repulsion, That it is influenced by various and different magnetic attractions, in all probability occasioned by the heterogeneous compositions in the great magnet, the _Earth_.
Notwithstanding all which, should the sagacity of some eminent philosopher be able to exhibit rules, whereby the quantity of the variation may be computed for future times, yet then such a review, as we have now made, will be necessary at a proper interval, to prove the truth of them: and should no such rules appear, then will a continued succession of such reviews be necessary so long as commerce and navigation subsist among us. What we have now done is intirely for the public service, the sale of the former chart never having made good its expence; and we propose to continue our endeavours for another review, at the proper time, if we shall then be alive, and capable of the task: but as the contrary may probably happen, we beg leave to conclude with recommending such a continuation, in the strongest manner, to such of the members of this Royal Society, or others, who may, at the proper intervals, have leisure and ability for such a performance. We are, with the greatest deference, Your Lordship’s, And the Royal Society’s, Most faithful and most obedient Servants, William Mountaine. James Dodson. _A_ TABLE, _exhibiting the different Variations of the_ MAGNETIC-NEEDLE _in the more frequented Oceans, from the Year 1700 to the Year 1756_.
We have been informed, that in Hudson’s-Bay, there has been very little alteration in the variation of the compass during the twenty years last past. XLII. _An Account of some extraordinary Tumors upon the Head of a labouring Man, now in_ St. Bartholomew’s _Hospital. By_ James Parsons, _M.D. F.R.S._ [Read Nov. 10, 1757.] THIS poor man, whose name is John Tomlinson, gives this account of himself: That he was born at or near Rotherham in Yorkshire, and is now about 25 years of age: that when he was a boy of four or five years old, at play with other children, he received a blow from one of them upon the top of his head; and believes that hurt, he then received, was the beginning of the appearances, that are represented before you. _See_ TAB. XIV. The tumor upon the top of his head, however, grew first, and, after having spread all over the vertex, extended gradually downwards over his right shoulder, and forwards over the _os frontis_, on the same side, till it stretched downwards into a lax flabby substance all over the right side of his face and shoulder: then the upper of the three anterior tumors arose from the large one; the middle one from the _ala nasi_, pulling it down by its weight, as you see it in Figure 1.[198]; and the lower one was pendulous from the inside of the great tumor by a narrow neck. These are the appearances which present themselves at first sight; but those under the great tumor are no less extraordinary; for, upon lifting up the great tumor, and looking up under it, his right eye comes in sight, with which he sees very well, and the eye is clear and sound; but the under lid is pulled down, and stretched to six or seven inches long, to which a tumor hung also, as large as that anterior one at the chin, the lowest of the three; besides several flaps and _rugæ_ of skin, and smaller tumors.
If we compare this growth of the frontal bone with that of other _exostoses_, I believe there may this difference be rationally observed; that other _exostoses_ are generally attended with ulcerous tumors, which are for the most part cancerous; and these may commence at any age. I have now drawings, taken from the right hand of a man of 50, which represent risings of the _radius_ and _ulna_, with the fingers, to a most frightful degree; and these begun but six years before, and are attended with foul running ulcers; and now the bones of the arm and hand, on the left side, are beginning to have the same appearances: whereas the frontal bone of the present subject appears sound, as far as we are able to judge by examination: nor does there appear the least disposition to ulceration in any part of it. When this is the case, the growth generally begins while the subjects are young; upon which we shall be more particular a little further on. His sensation upon every part of these tumors, is exactly like that of every other part of his skin, having not the least uneasiness upon being handled. This poor man worked at day-labour in the fields till some months before he came to town.
Perhaps it may not be improper to lay down the dimensions of these tumors, as the case is so extraordinary; for the size of them is almost incredible: but I made my drawing in the presence of several of the gentlemen of that hospital, who allowed it to be very exact, and precise in the expression of the parts, as well as in the dimensions. The vertical tumor is about seven inches diameter at the basis, where the bony edge is felt, mentioned before, and about four inches high from that edge. From that edge, or the basis of the vertical tumor, to the bottom of the great tumor, is ten inches; so that the length of both, from the vertex to the end of the great one, is about 14 inches: and upon viewing it, when he turns his side towards you, the whole mass is eight or nine inches over all the way; hard at top, and flabby downwards, hanging in kinds of plaits. From the eye to the opposite outline of the great tumor is six inches; and lower down, from the left corner of his mouth to the opposite outline of the same tumor, eight inches. The upper small tumor, over the nose, is one inch three quarters long by one inch and a half; the middle tumor is two inches long from the _ala nasi_, to which it hangs, and of the same breadth; and the lowest tumor, shaped like a goose’s egg, is four inches and a half long by near three inches over.
This man is under the care of Mr. Crane, an eminent surgeon of St. Bartholomew’s Hospital, who has just now taken off the lowest of these three anterior tumors, and also the tumor mentioned, which hung underneath to the under lid of his right eye. He intends proceeding to take off that at the _ala nasi_ next, and so on till he takes away all the smaller tumors first: afterwards the larger will be considered. The substance of those cut off was intirely fat; nor was there the least speck of blood in the lowest of the three smaller tumors; but there was an hæmorrhage from a vessel divided in taking off that hanging to the right eye-lid; which soon yielded to the methods he made use of, and went on successfully till quite healed. It is pity no one of the people of condition in the country, where this poor man lived, took notice of him while he was a lad; because, when the vertical tumor begun, or even after it had made some progress, if he had been sent up to any of our hospitals, there would have been no difficulty in curing him. This leads me to some precautions, which, I hope, will render my account of the case of some use, considered in a physiological light; which was my intention in thus laying it before this learned Society.
There is a great deal of difference between injuries received in young subjects and in adults. In the latter, the consequences are not apt to be of so dangerous a nature as in the former (except indeed where there happen violent fractures or wounds, which immediately dispatch the person, young or old); because, in such as are so far advanced in years, as that the parts have done growing, or, in other words, are incapable of carrying the person to any larger size, preserving the natural proportion, a tumor arising from a blow on the head would be merely local, without extending to any neighbouring parts in so extraordinary a manner: but in children, as in the case before you, a tumor may increase every moment from a blow, and spread itself to the neighbouring parts, to the ruin of the child, unless timely care be taken to prevent it; because in such young subjects the parts are continually growing, the vessels enlarging in their diameters, and carrying more and more nutrition to every point, in proportion to the nature of each individual organ, always preserving such an equilibrium, in the distribution of the nutritive juices, as is proper to secure the due proportion of every part as it increases: but when a tumor arises from a blow in such a growing subject, if no wound is made, nor suppuration brought on in the tumor, then the parts of the tumor being only weakened, the equilibrium is destroyed, a greater flux of juices than ordinary is carried to it, the due resistance being impaired, and a luxuriancy of growth is produced in the place of the injury, which greatly exceeds that of the rest of the body; and will most certainly continue in the same manner, during the growth of the subject, when once thus begun.
And but one alive above 87, who is 91. The Number of People 425. The Number of Houses 90. The Number of Acres 2245. whereof ⅙ is waste. I do not offer such trifling numbers as these, as a fit subject to build a canon of life upon; but only as they may furnish us with a few particulars, which may throw some small light upon a subject hitherto very little cultivated: and as what has been advanced this way has been always taken from great cities, a little from the country perhaps may not be disagreeable. The first observable in my numbers is, that the two infancies of human life are exactly equal; i. e. as many die above 60 as under 2 years of age; and that these two periods of life are by much the most sickly, five eighths of the whole, nearly, dying in these two stages, which renders the intermediate numbers very small. This will give us some reason to suspect, that capital cities are very improper to estimate the probabilities of life from. The continual flux of people from the circumjacent country, to seek for employment, makes the decrements of life seem much larger than they really are. London is very remarkable upon this account; and Breslaw must receive pretty large accessions, as a very considerable manufacture is carried on there.
The second thing I would observe from my table is, that it confirms what Dr. Brackenridge observes of the Isle of Wight; _viz._ that the births are to the burials as 2 to 1 almost; ours being as 15 to 8 nearly. Now if this is the case of all the country places in England, it will give us a strong presumption, that the increase of mankind is much quicker than Dr. Derham’s proportion of 1 to 12; especially if we consider, Thirdly, That of the living not 1 in 50 dies yearly; and this in a village not very healthy. We are situated upon the celebrated Lamborne stream, which dries up generally in August, and leaves a stagnated water, and stinking mud, at a critical season of the year, which bring on a putrid fever, and make our place sometimes very sickly. In the year 1751 we buried 17, and in 1756. 11: and therefore we may presume, that in the healthiest parts of the nation, the proportion is still greater, perhaps not one in 60. In order to clear up this, it were to be wished, that the actual number of the people was known, where-ever the bills of mortality are exhibited. All reasoning without this preliminary is really not much better than groping in the dark.
A fourth thing observable from my numbers is, that the quantity of people allotted to a house is too big in all former calculations: for if we divide 425, the number of people, by 90, the number of houses, it gives but 4.72, which is not quite 4¾ to a house; and therefore 5 to a house, I believe, is as much as ought to be allowed, taking the nation all together. Now if the number of houses, taken in Queen Anne’s time, be any thing near the right, with one fourth more allowed for cottages, according to Dr. Brackenridge’s computation, we shall make the people in England, allowing 5 to a house, to be only 4,556,550. which appears, at first sight, to be too small a number. However, of Shefford I would beg leave to observe, (and it is far from being the poorest of villages) that more than two thirds of all the houses are downright cottages, and must be excluded, one as much as another, from any proposed assessment. Upon this foundation we must grant, that at least half the houses in England, take towns and all together, must be cottages, and plead an exemption from taxation all alike. And thus the number of houses will be 1,458,096. which, multiplied by 5, will give us the number of people, 7,290,480. If to this we add the proposed increase, 789,558. we shall have 8,080,038 for the number of people now alive in England.
The fifth and last thing I would observe from my numbers is, that we may hence guess at the number of people in the whole kingdom: for if 1871, the good acres in Shefford, demand 425 persons for their cultivation, then will 25,300,000 good acres in England require 5,704,168 for the cultivation of the land only. Now supposing one third part of the people only to live in towns, above what is necessary for the cultivation of the land belonging to such towns, then we must add 2,852,084 to the above sum, which gives us 8,556,252 for the number of people in England. It may probably here be said, that this is but little better than reckoning at random. Indeed I allow it is so. But then I must beg leave to observe, that it has full as good a foundation to stand upon, as any calculation, that I have seen hitherto advanced. It has one _datum_, viz. a certain number of persons to a certain number of acres. It ought to be noted at the same time, that we are an inland place, have no sort of manufacture carried on, and consequently no accession of strangers. If we examine the calculation arising from the consumption of wheat, we shall see some reason to suspect, that the number of inhabitants in England is not short of eight millions. I am persuaded I do not exaggerate, when I affirm, that three fourths of the people north of Trent, and in Wales, do not eat wheat: and as this is near a third part of England, it will follow, that one fourth of the whole is left out of the calculation, and that we must add near two millions to it to make it complete.
Again, I compute, that in my parish there are killed annually 160 fat hogs, _viz._ above one to three persons; and that this humour of pig-killing prevails over half of England at least, and is in some measure indulged in all parts. Now we will suppose, that there are but six millions of people in the nation, and that what is killed in the northern half makes up for what is deficient by reason of towns in the southern half; we must from hence conclude, that a million of fat hogs are killed in England every year. Now one hog with another takes two quarters of corn, sometimes barley, sometimes pease: if we put half barley, we shall be under the truth. And here we shall have a million quarters of barley, not only to balance the exportation of wheat, but also to be equivalent to, as much bread-corn as will maintain a full million of people.
Farther, it is well known, that the greatest part of the corn-trade is, of late years, got into the hands of millers: and it has been whispered about for a considerable time, and, I think, now the millers do not deny it, that _some_ whiting is carried to all the great mills. The excuse alleged for it is, that it makes the flour _wet_, and consequently _bake_, the better. I am rather inclined to be of opinion, that it is to give a colour to something that wants colour. And indeed, who-ever tastes the common bakers bread against a piece of genuine wheat-bread, will have some reason to suspect, that all is not gold, that glitters. Every body knows, that the millers buy large quantities of barley and pease, they say, to fat hogs: but then they have pollard, middlings, _&c._ to fat them with; and so may possibly mix the barley and pease with wheat to grind. But as this is all surmise, I would have no more weight laid upon it than it deserves. The next article is of the same nature; I mean, something of a mystery in trade; and therefore to be touched very gently. What I would hint is, that it is the opinion of many very intelligent persons, that a good deal of malt is made, which does not pay the excise. I do not pretend to ascertain the quantity: perhaps one eighth may not be an extravagant supposition. And if this be the case, we shall find as much barley, as will weigh against bread for half a million of people.
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