Royal Society (Great Britain).

The Philosophical transactions of the Royal society of London, from their commencement in 1665, in the year 1800 (Volume 8) online

. (page 9 of 85)
Online LibraryRoyal Society (Great Britain)The Philosophical transactions of the Royal society of London, from their commencement in 1665, in the year 1800 (Volume 8) → online text (page 9 of 85)
Font size
QR-code for this ebook


be reduced to a very small quantity. However, for this reason, and also be
cause the instrument seemed to be attended with greater inconveniencies, both
in its construction and use, than the other, Mr. Hadley did not think it neces-
sary to give any more particular description of it.

Of a large Bony Substance found in the fVomb. By Edward Hody, M. D.,

F.R.S. N°440, p. 189.

In examining the pelvis of a woman, 57 years of age. Dr. H. found a large
bony substance, contained in the womb, and so strictly united to it, that they
seemed to be one and the same body. On cutting the substance asunder, he
observed, that the ossification went no farther than the thickness of a shilling;



VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. fl/

the part immediately under the ossification was like firm flesh, and this flesh
was softer and softer the nearer to its centre.

He thinks it unnecessary to remark, that the woman never had but 1 child,
of which she was delivered about 1^ years before she died.

Her chief complaints, for some years, were a short cough, great difficulty in
breathing, frequent uneasiness in making water, or in going to stool, and a
constant weight, or bearing down, on the parts of generation.

But the immediate cause of her death was an asthma; for she had only one
lobe of the lungs left that was perfectly sound ; the rest adhered firmly to the
pleura, were very much contracted, and in some places scirrhous. i

Experiments concerning the Impregnation of the Seeds of Plants. By James

Logan, Esq. N° 440, p. iQ2.

As the notion of a male seed, or the farina foecundans, in vegetables, is now
very common, Mr. Logan only mentions such observations concerning it, as
may have some tendency to that subject. And first it appears, from Miller's
dictionary, that M. GeofFroy, from the experiments he made on maize, was
of opinion, that seeds may grow up to their full size, and appear perfect to the
eye, without being impregnated by the farina, which possibly may in some cases
be true ; for there is no end of varieties in nature. But in the subject he has
mentioned Mr. L. believes it is otherwise, and that Mr. G. applied not all the
care that was requisite in the management.

In the spring Mr. Logan resolved to make some experiments on the maize,
or Indian corn. In each corner of his garden, he planted a hill of that corn,
and watched the plants when they grew up to a proper height, and were push-
ing out both the tassels above, and ears below ; from one of those hills, he cut
off the whole tassels, on others he carefully opened the ends of the ears, and
from some of them cut or pinched off all the silken filaments ; from others he
took about half, from others ^ and ^, &c. with some variety, noting the heads,
and the quantity taken from each : other heads again he tied up at their ends,
just before the silk was putting out, with fine muslin, but the fuzziest or most
nappy he could find, to prevent the passage of the farina; but which would
obstruct neither sun, air nor rain. He fastened it also so very loosely, as not
to give the least check to vegetation.

The consequence of all which was this ; that of the 5 or 6 ears on the first
hill, from which he had taken all the tassels, from whence proceeds the farina,
there was only one that had so much as a single grain in it, and that in about
480 cells, had but about 20 or 21 grains ; the heads, or ears, as they stood on

VOL. VIII. I



58 PHILOSOPHICAL TRANSACTIONS. [aNNO 1 736.

the plant, looked as well to the eye as any other ; they were of their proper
length, the cores of their full size, but to the touch, for want of the grain,
they felt light and yielding. On the core, when divested of the leaves that
cover it, the beds of seed were in their ranges, with only a dry skin on
each.

In the ears of the other hills, from which he had taken all the silk, and in
those that he had covered with muslin, there was not so much as one mature
grown grain, nor other than as mentioned in the first : but in all the others,
in which he had left part, and taken part of the silk, there was in each the
exact proportion of full grains, according to the quantity or number of the
filaments left on them. And for the few grains found on one head in the first
hill, he immediately accounted thus : that head, or ear, was very large, and
stood prominent from the plant, pointing with its silk westward directly to-
wards the next hill of Indian corn ; and the farina, he knew, when very ripe,
on shaking the stalk, will fly off in the finest dust, somewhat like smoke. He
therefore judged that a westerly wind had wafted some few of these particles
from the other hill, which had fallen on the styles of this ear, in a situation well
fitted to reieive them, which none of the other ears, on the same hill, had.

Mr. Logan is positive, by his experiment on those heads, that the silk was
taken quite away, and of those that were covered with muslin, none of the
grains will grow up to their size, when prevented receiving the farina to im-
pregnate them ; but appear, when the ears of corn are disclosed, with all the
beds of the seeds, or grains, in their ranges, with only a dry skin on each,
about the same size as when the little tender ears appear filled with milky juice
before it puts out its silk. But the few grains that were grown on the single
ear, were as full and as fair as any ever seen ; the places of all the rest had only
dry empty pellicles, as described ; and probably the same holds generally in the
whole course of vegetation ; though it may not be safe to pronounce absolutely
upon it, without a great variety of experiments on different subjects. But there
are few plants that will afibrd so fine an opportunity of observing on them, as
the maize, or Indian corn ; because its styles may be taken off or left on the
ear, in any proportion, and the grains be afterwards numbered in the manner
abovementioned.

^Some Observations of the Eclipses of Jupiter s Satellites, made by Geo. Lynn,
Esq. at Southwick, Northamptonshire. N° 440, p. 1Q6.

The account of these eclipses is of no use now.



VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. 5Q

Concerning the High Tide in the River Thames, on Feb. J 6, 1735-6. By Mr.

Tho. Jones N" 440, p. IQS.

Mr. Jones having in a former Number given an account of the tide's flowing
on the 8th of March, 1725-6, which then flowed 20 feet 5-j- inches, as he
took it by a level from that high water mark to low water the next morning,
and was 4 inches higher than had been known for 40 years before. He now
adds, that having marked that high tide on a post, on Monday the l6th instant,
(Feb. \(), 1736) the tide rose at the same place 6^ inches above that mark, and
flowed near 2 feet the last half hour but one before high water.

If the tide had flowed its full time, it would have flowed half an hour longer,
and would have drowned the whole level.

A Singular Cutaneous Affection, By Ahr. Vater, M. D. Professor of Anatomy
and Botany in the University of fVittemberg and F.R.S. An Abstract from
the Latin. N° 440, p. IQQ.

In the Phil. Trans. N^ 424,* a history is given of a very uncommon case of
diseased skin, occurring in a young labourer. A case parallel to this occurred
in Germany in a young girl, who had been previously affected not only with
swellings of the limbs and body (to which various domestic and empirical reme-
dies had been applied) but also with a large, hard tumor between the shoulders,
which was removed by discutient applications. But after the discussion of these
tumours, a dry and hard crust or scab began to form, on the feet and hands,
especially in the soles of the feet and palms of the hands, and this incrustation
projected so much from the ends of the fingers and toes, that the patient could
neither lay hold of any thing nor walk. The incrustation scaled off at intervals,
especially after the use of various ointments ; but at such times the girl was
always ill, being swelled in her body, and troubled with a sense of oppression,
and griping pains of the bowels, which symptoms continued until the incrusta-
tion was removed. She was at length cured by laxative mercurial medicines,
and decoctions that purify the blood. Examined by the microscope, the in-
crustation appeared to be nothing more than the cuticle expanded and in-
durated. Dr. V. was informed of another similar case occurring in a young wo-
man, likewise a German, whose hands and feet, with the fore-arm, were
covered with a crust or scab, which scaled ofl^ twice a year, and resist'^d all the.
remedies which had then been tried. This patient laboured under an ob-

* Vol. vii, p. 543 of these Abridgments.
I 2



60 PHILOSOPHICAL TRANSACTIONS. [aNNO 1736.

struction of the menses, which was supposed to give rise to the diseased state
of the skin.

Experiments on the Vibrations of Pendulums. By the late W. Derham, D. D.

F.R.S. N°440, p. 201.

The account Mr. Bradley gave in Philos. Trans. N°432, of observations made
at Jamaica by Mr. Campbel, with a nice pendulum-clock of Mr. Graham's
making, brought to mind some experiments Dr. Derham made some years be-
fore, which may be of use in observations of this nature.

The first he notices are some experiments made in the year 1 704, with ex-
cellent instruments, on the vibrations of pendulums in vacuo ; which were
published in the Philos. Trans. N° 294. The sum of which is, that the vibra-
tions in vacuo were larger than in the open air, or receiver unexhausted : also
that the enlargement or diminution of the vibrations, was constantly in pro-
portion to the quantity of air, or rarity, or its density, left in the receiver of
the air-pump. And as the vibrations were larger or shorter, so the times were
augmented or diminished accordingly, viz. 2 seconds in an hour slower, when
the vibrations were largest, and less and less, as the air was re-admitted, and
the vibrations shortened.

But notwithstanding the times were slower, as the vibrations were larger, yet
he had reason to conclude, that the pendulum really moved quicker in vacuo,
than in the air, because the same difference, or enlargement of the vibrations,
as -^ of an inch on a side, would cause the movement, instead of 2 seconds in
an hour, to go 6 or 7 seconds slower in the same time ; as he found by nice
experiments.

The next experiments he made at several times, in 1705, 1706, and 17 12, by
the help of a good month-piece, that swings seconds. The weight that then
drove it, was about 12 or 13 pounds, and it kept time exactly by the sun's mean
motion : but by hanging on 6 pounds more, the vibrations were enlarged ; but
yet the clock gained 13 or 14 seconds in a day.

And as the increase or diminution of the power that drives the clock, ac-
celerates or retards its motion, so doubtless does cleanness or foulness affect it,
as also heat and cold ; for all have the same effect on the jiallets and pendulum.

The last experiments he made in 1716 and 17 18, to try what effects heat
and cold had on iron rods of the same length, or as near as he could to those
that swing seconds. He made many experiments with round rods of about a
quarter of an inch diameter, and with square rods, of about three quarters of an
inch square. The effects on both which were the same.



/



VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. 6l

At first he took the exact length of the rods, in their natural temper. Then
he heated them well in a smith's tire, from end to end, nearly to a flaming
heat; by which means they were lengthened -i^ o( an inch. Then he
quenched them in cold water; which made them y^ of an inch shorter than in
their natural state.

Then he warmed them to the temper of his body; by which means they were
about -j-i-5- of an inch longer than in their natural temper.

Afterwards he cooled them in a strong frigorific mixture of common salt and
snow, which shortened them -pf-j- parts of an inch.

Afterwards he measured these rods, when heated in a hot sun, which length-
ened them -T-*Tr parts of an inch more than their natural temper.

All these experiments seem to concur in resolving the phenomenon of pen-
dulum clocks going slower under the equator than in the latitudes from it; but
yet he has too good an opinion of Sir Isaac Newton's notion of the spheroidal
figure of the earth, easily to part with it; and therefore he leaves it to the con-
sideration of others, how far the figure of the earth, and how far heat and
cold, and the rarity and density of the air, are concerned in that pheno-
menon.

The Construction and Use of Spherical Maps, or such as are delineated on Por-
tions of a Spherical Surface. By Mr. John Colson, M. A. F. R. S. N° 440,
p. 204.

Geographical maps, and hydrographical charts, though representations of a
convex spherical surface, were first delineated on planes, as being the most easy
and obvious, though not the most natural and accurate representations; and
they are sufiiciently near the truth, when the part of the earth or seas described,
is not of a very large extent. Such as these have been usually called chorogra-
phical and topographical maps ; but when the map is any thing general, or is to
contain any large tract of the earth or seas, suppose, for instance, one of the
four quarters of the world, then, when they are projected, or represented on a
plane, the parts must necessarily be distorted, one way contracted beyond the
truth, another way dilated, so as to give no just idea of the whole. Nor can
this distortion be possibly avoided, when any considerable part of a spherical
surface, by any projection whatever, is to be represented on a plane. This
distortion is indeed always regular, and according to certain laws; so that
knowing the nature of the projection, it may tolerably well be allowed for.
But to do this scientifically, requires much skill and accuracy in the maker, as
well as proficiency and experience in the peruser; and therefore not so proper
for an introduction to learners, in the rudiments of geography. Young minds



62 PHILOSOPHICAL TRANSACTIONS. [aNNO 1736.

are apt to receive wrong notions and prejudices from them; at least they cannot
be rightly and easily instructed by them.

To obviate this inconvenience, geographers have contrived the terrestrial
globe, on which they endeavour to delineate all the parts of the earth's surface
in their natural state, as to longitude, latitude, distance, bearing, magnitude,
&c. which being a true and genuine representation of the whole superficies of
the earth, as far as it is yet known, is the best adapted for conveying just no-
tions to young minds, and for preventing all false conceptions and preposses-
sions. After the first rudiments of geography have been imbibed from hence,
they will be then prepared for the use of plain maps; and they will afterwards
find, that large projections of particular countries, kingdoms, and provinces,
in piano, will be of excellent service for their further improvement in this useful
and necessary science. Nor will they now be in any danger of being misled
by such maps, though they are not so just and niatural representations of the
terrestrial globe.

Now the same conveniencies that may be derived from the whole globe, may,
in proportion, be had from any notable portions of it; as a hemisphere, a
quadrant, a sextant, an octant, or other part. But with this advantage besides,
that these partial spherical maps will not only be much less cumbersome, and
more manageable than a whole globe, but may be made much more accurate
and particular, as they are capable of being formed to a much larger diameter,
than a globe can conveniently be made to. The maps may first be printed on a
plane, as is usual in the common globes, and then pasted on thin convex shells
of pasteboard, formed to the intended radius. The forming of these spherical
coats of pasteboard will be a matter of no great difficulty, even to as large a
diameter as shall be desired ; but the chief art will be required in projecting
the maps in piano, after the simplest and exactest manner, so as they may adapt
themselves, with as little error as possible, to a spherical surface. For a
plane surface cannot be converted into a spherical surface without some error.
The best method of doing this, with the least possible error, may be as
follows.

Instead of the usual slips or gussets, as is the manner of globe-makers, which
are comprehended between two meridians at some distance, and are formed only
tentatively and mechanically, without the help of any just theory, we may divide
the whole spherical surface into parallel portions, or zones; that is, into parts
terminated by two parallels to the equator, at the distance suppose of 10 degrees.
As if the first of these portions, or zones, were at the equator itself, and ex-
tended to 5 degrees of latitude on each side of that circle; the second zone
would be at the parallel of 10 degrees of latitude, and would extend to 5 de-



VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. GA

grees of latitude on one side, and to 15 degrees of latitude on the other side of
that parallel ; and so of the succeeding zones.

Now we may conceive the first of these portions, or zones, to e converted
from a spherical surface to a plane in this manner, without sensible error; let
the middle line of this zone, that is the equator, continue in its situation, and
let the segments of the meridians on each side be conceived to unbend them-
selves gradually, till they are extended into right lines perpendicular to the
equator; then will that which was before a zone, or portion of a spherical
surface, with a small alteration become a portion of a cylindrical surface, cir-
cumscribed about the sphere; whose breadth is every where equal to 10 degrees
of the sphere, and whose circumference is equal to the equator. And thus
every parallel to the equator, as far as that of 5 degrees of latitude on each
side, will be stretched and extended into a circle as large as the equator; but
they will all keep the same distance from one another, and from the equator,
that they had before. This extension, or alteration, will be every where regular
and uniform, and will be but very little, even where it is most; for the least of
these circles, which is the parallel of 5 degrees of latitude, has the same pro-
portion to the circle it is stretched to, or the equator, as the sine of 85 degrees
has to the radius, or as 996 1 947 to 10000000; which approaches very near to
a ratio of equality. And now it will be easily conceived, that without under-
going any other alteration, or distortion, this portion of a cylindrical surface
may be rectified, or extended into a plane parallelogram, whose length will be
equal to that of the equator, and whose breadth will be equal to an arch of 10
degrees of the same equator.

Consequently, by an operation that will be just the reverse of this, if on a
plane we delineate such a parallelogram as this, we may then lay down all the
places that are contained in it very exactly, in their proper situation of longi-
tude and latitude, and then apply its middle line, or equator, to that of a globe
of a due magnitude, which will then become a portion of a cylindrical surface,
circumscribed about the globe. Then by pressing it close to the body of the
globe, we shall cause it to contract itself a very little, but regularly, which
contraction will be only according to longitude, and not at all according to lati-
tude; and then the cylindrical surface will be changed into that of a sphere, and
will become the first spherical zone before described, with all its delineations in
their due position, without sensible error.

In like manner in the second spherical portion, or zone, comprehended be-
tween the parallels of 5 and 15 degrees, whose middle line is the parallel of
10 degrees, we may conceive the segments of the meridians to unbend gradu-
ally on each side, and to extend themselves into tangent right lines, which



64 PHILOSOPHICAJ. THANSACTIOX8. [aKNO IJSO.

therefore will form a s^ment of a conical surface, still touching the globe in
the parallel of lO degrees of latitude. The axis of this cone will coincide with
the prolonged axis of the globe, and the side of the cone, which is to be esti-
mated from the vertex to the circle of contact, will be the co-tangent of the
latitude, or the tangent of 80 degrees. Now this portion of a conical surface
may easily be conceived to be unrolled, or to be expanded into a plane surface,
without undergoing any other alteration, and then it will become a portion of
a sector of a circle ; which portion will have for its length, or middle line, an
arch of a circle described with the said tangent, as a radius, whose length will
be the same as the parallel of contact, and its breadth will be equal to an arch
of the equator of lO d^rees, as before. This s^ment of a sector of a circle,
so produced, may therefore be easily described in piano, and within it may be
inserted all the places belonging to it, according to their longitude and latitude.
Then it must be applied to the globle, so as that its middle line shall coincide
with the parallel of JO d^rees; then by pressing it may be bent to the surface
of the globe, every meridian to its respective representative, by which it will
imiformly contract a little according to longitude, but not at all according to
latitude. And thus the globe will be covered as ^r as 15 d^rees of latitude.

The next zone, or that belonging to the parallel of 20 degrees, may be thus
constructed a priori. On a plain paper, with radius equal to the tangent of JO
degrees, describe an arch, whose length is equal to that of the parallel of 20
d^ees; as also two other concentric arches on each side, at a distance from
the middle arch equal to an arch of 5 degrees. This will be the required s^-
ment of the circular sector, in which are to be inserted all the places belonging
to it, according to their longitude and latitude. Then the middle line or arch
is to be applied to tlie parallel of 20 d^rees on the globe, and the segment of
the conic^ surface thence arising, is to be duly contracted as before, or pressed
close to the globe ; by which means this zone will also be completed. And in
the same manner we are to proceed to the succeeding zones, till the whole globe
is covered. And the method will not differ in any material circumstance, if
instead of a whole globe, we are to construct any part of it only, or what is
here called a spherical map.

^ Copy of an anderu Chirograph, or Conveyance of Part of a Sepulchre, cut
in Marble, lately brought from Rome, with sotne Observations on ii by Roger
Gale, Esq. r. P. S. N»44l, p. 211.

Tliis marble lately arrived from Rome, and dqxjsited in the noble museum of
Sir Hans Sloane, is a most valuable piece of antiquity, exhibiting a complete
formula of a chirograph, or conveyance of one part of a burying-place from one



VOL. XXXIX.] PHILOSOPHICAL TRANSACTIONS. 65

family to another, but neither of them of any note, seeming by their agnomina
to have been only liberti, or descended from such. Agricola indeed is a
Roman name, but those of his wife Lacena, and his son Protus, are both
Greek.

By this chirograph Herennius Agricola obtains from Titus Flavins Artemi-
dorus, a right to 4 ollaria, which were niches or repositories, where they placed
cineraria, urns, or vessels of stone or earth, containing the ashes of the dead,
and were here 53 in number.

This monument was situated on the left side of the Via Salaria, which ran to
the north-west of Rome from the Porta Collina. It stood in the ground of
Volusius Basilides, and the consideration for the conveyance of it is one Sesterce.
It is very usual in sepulchral inscriptions to find the monument of one family in
the field of another, the prpprietor of the monument reserving the right of
that to himself when he sold the ground; or purchasing so much ground from
the owner as was suflicient for erecting the monument. All sepulchres, when
once a body was interred therein, were esteemed as religious and sacred, and
were not to follow the possession of the field.

The stone is turned with an arch at top; the whole length of it is 17\ inches;
the breadth at the bottom is lOj^ inches, and at the base of the arch 12^, as it
widens gradually upwards. The letters are cut in a small indifl^erent character;
that of the E and the F are remarkable, being always formed in this manner
E,/. It was probably placed over or between the four niches, or ollaria, granted
to M. Herennius Agricola, in this monument, by T. Flavius Artemidorus, to de-
clare and assert the right and possession of them to the former, and his family,



Online LibraryRoyal Society (Great Britain)The Philosophical transactions of the Royal society of London, from their commencement in 1665, in the year 1800 (Volume 8) → online text (page 9 of 85)