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 49 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 49 of 85)
Font size
QR-code for this ebook

Paris and Dunkirk, he owns that they cannot be much out of the way ; being
in some measure confirmed by M. de la Hire, in the year l683, and by M.
Cassini himself. Yet Mr. Celsius observes, that the basis on the sandy plain
shore, near Dunkirk, when measured again, differed three feet from the for-
mer measurement ; which is a much greater difference than that M. Celsius and
the other gentlemen found, in measuring a much longer line twice over, which
was but 4 inches.

As to the astronomical observations taken by the 6-foot sector, whose limb
of 12 degrees was divided only at every 20" ; it is true, M. Cassini examined the
instrument several ways, at Paris, after his return thither ; but that a correc-
tion, owing to the change of centre, might be safely applied to the observations
at Dunkirk, the examen of the centre should also have been taken at Dunkirk ;
it being uncertain, whether this alteration or aberration of the centre, was caused
by the journey to or from Dunkirk.

The difference of 41" between the observations taken to settle the true mea-
sure of the arc of the heavens, seems to be enormous. Perhaps the stars were
not lucid enough to be well observed by the 3-foot tube ; but might they not,
for a due degree of accuracy, have been viewed through the 9 or 10-foot te-
lescope ?

Our author prefers the observations of 1719} made after the return to Paris,
to those made before ; because made at the same time of the year with those of
Dunkirk, and so not standing in need of Mr. Bradley's correction : though this
caution perhaps may be thought not necessary here, where the errors of the


observations are greater than the correction itself. Mr. Celsius remarks fur-
ther, if the difference of latitude between Dunkirk and Paris be supposed to be
2° 12' 12V'. which is a mean between 4 others he mentions, the length of a
degree will amount to but 56,395 toises. And if the observations at Malvoi-
sine and Amiens, be counted according to Mr. Bradley's theory, for the inter-
val of a month between the observations, the length of a degree will come out
to be 56,926 toises : which is 135 toises less than the length of a degree, found
by measuring the whole length of France ; and 134 less than that of Mr. Picard,
so highly approved of by Mr. Cassini, as confirming his own.

Mr. Celsius having finished his remarks on the observations made in the
north part of France, extending from Paris to Dunkirk, proceeds to examine
those taken in the south, from Paris to Collioure, near the borders of Spain,
and the Pyrenean mountains. By the former, a mean degree was found to
consist of 56,960 toises, by the latter 57,097; and consequently the earth is
an oblong spheroid.

Mr. Celsius, in examining these observations, which were taken under the
conduct and direction of the late M. Cassini, in 17OO, first considers the struc-
ture and goodness of the instruments used ; then the accuracy of the astronomical
observations for finding the difference of latitude ; and, in the last place, the
trigonometrical operations for determining the distances of places ; especially
the two extremes under the same meridian.

The principal instrument M. Cassini carried with him, was, a limb of 12
degrees, whose radius was indeed 10 feet, but divided only into degrees and
minutes ; the other parts were added to it at Perpignan. Here Mr. Celsius
observes, that the finding the true centre of this limb was, and still is, a very
difficult and troublesome problem to a good artist ; that no mention is made,
whether the position or place of this centre, and the divisions of the limb, were
ever examined at Paris or Collioure, though the carriage of the instrument
through so long and rough a way, could not but make some alteration in the
place of the centre.

It is true, the zenith distance of Capella, taken by it at Paris, was confirmed
to be right by another instrument ; but it cannot be concluded that the zenith
distance of the same star, taken at Collioure by this instrument, and not con-
firmed there by another instrument, must be true also. For the point of di-
vision, answering to this distance in the limb, was not examined ; and a centre
wrong placed may by accident give the true zenith distance, viz. when the
true and erroneous centre happen to lie in the same perpendicular to the

The exceptions taken to the astronomical observations, for finding the dif-



fereiice of latitude between Paris and CoUioure, are, in tlie first place, that
though 5 stars were observed at Collioure and Paris, yet one only was made use
of, viz. Capeila. That the difference of latitude by Capella is 6° 18' 57". If
Lucida Lyra had been used, the difference would have been but 6° 17' T' ; but
by the right shoulder of Auriga, 6° 1 9' 25". Hence arises the uncertainty or
difference oil' 18" between the greatest or least of their observations ; that
the late M. Cassini makes the difference 37" less than M. Cassini, who accounts
for this difference from the observations being taken by an ordinary instrument ;
but the instrument is the same which was used to take the altitude of the pole
of Amiens, which was very near that found by Mr. Picard.

As to the trigonometrical operations for finding the distance of places, M.
Celsius thinks they labour under considerable uncertainties ; not only on ac-
count of the many difficulties they met with, viz. the mountainous countries,
want of proper signals, &c. so that convenient triangles could not be formed ;
but add to all these, that several of the triangles had but two angles observed,
and some of these angles too acute ; whence, as M. Cassini himself very justly
observes, in his examination of Snellius and Riccioli's observations, great errors
may arise. M. Picard thinks all angles less than 20° ought to be avoided ; as
also that the triangles should be contrived so as to have sides of a due length,
neither too great nor too small. Then follow 16 triangles, wherein one or more
of these inconveniencies are to be found.

It may be said, the whole of these observations and measures of M. Cassini
seem to be sufficiently confirmed, if not ascertained ; since the principal base
in Roussillon was found, when computed, to differ but 3 toises from the same
as it was actually measured ; and that, after some due corrections, it was made
to agree with the greatest exactness. M. Celsius replies, why are we not told
what those corrections were, that we may see whether they were really neces-
sary or no? Why were they not taken notice of in the calculations of each
triangle ? Besides, the real length of the base, or the fundamental line in
Roussillon, is not fully ascertained, it not being measured more than once ;
whereas that at Dunkirk, and that of M. Picard, were measured twice ; and
there was more reason for doing so here than at Dunkirk, on account of the
uneven and almost ever-changing shore in Roussillon, from the restless over-
flowing sea.

The great number of the triangles, joined with the numerous small errors
of the angles, is another ground of uncertainty; for the errors in the angles,
though small, may make the distance of the parallels, of the two extreme
places, greater than it ought to be; and yet the principal sides, that is, those
that are made bases to the following triangles, continue the same. This made


it necessary to verify the sides, at least at every second degree, by measuring
the principal base twice over with due care; which might have been done, and
therefore should have been done, in a matter of so much nicety, as an attempt
to find the difference between 2 degrees so near one another, under the same

To show what bad consequences may arise from small errors committed in
observing the angles of several triangles, Mr. Olaus Hiorter, a curious and
ingenious friend of Mr. Celsius, has taken the pains to form the triangles of
M. Cassini between Bourges and CoUioure; so that the distance between their
parallels shall be considerably lessened; and yet the base in Roussillon, found
by computation, shall not, after due correction, differ sensibly, if at all, from
the same actually measured. In consequence of this, Mr. Celsius concludes
with observing, that the distance between the Royal Observatory, and the
perpendicular to the meridian of Collioure, deduced from the triangles of Cas-
sini, corrected after Mr. Hiorter's Method, &c. will amount to but 358,980
toises. This, divided by the mean difference of their latitudes, 6° ig' 1 1'',
will give 56,803 toises, for the length of a degree, one with another, between
Paris and Collioure, which is less than the length of a mean degree found by
M. Picard, and pretty near the truth : so that the degrees decrease as you go
towards the equator ; and consequently the earth is higher at the equator than
at the poles, as Sir Isaac Newton and Mr. Huygens believed.

The distance of the parallels of Paris and Collioure, by this method, is in-
deed less than that computed by M. Cassini; but this cannot reasonably be
complained of, since these computed measures of M. Cassini seem very capa-
ble of being lessened ; and it is no more than what M. Cassini himself has
done to the measures published by his father, which he has shortened by 325-^
toises. But however that matter be, whether this particular correction of M.
Cassini's distance, and consequently length of a mean degree, be admitted or
not, Mr. Celsius is fully persuaded, on the whole, that he has made it plain to
every unprejudiced reader, that these two sets of observations in France, are
not taken with such a degree of exactness, as to be depended on, in deter-
mining so nice a matter, in dispute for 50 years, as the true figure of the earth;
which was the thing proposed to be done by them.

Concerning a Place in New- York Jbr measuring a Degree of Lalittuie. By
Mr. J. Alexander. N° 457, p. 383. >

The mention of the French endeavours, to discover the figure of the earth
by observation, put Mr. A. in mind, that a very exact observation for that

3h 2


purpose might be made here, because Hudson's river is frozen over, from
New- York, up to Albany, and its course is very straight, almost due north,
and the distance between New- York and Albany is above 150 miles; New-
York is in latitude of 40° 40', nearly ; so that the length of above 2° of lati-
tude on the earth might be measured here, with much more exactness than it
was possible in England or France, because of the ascents and descents, and
curved lines, which they would continually be obliged to make allowances for.
From all which difficulties the mensuration here on the ice would be entirely

On the Antiquities of Prussia. By James Theodore Klein, Seer, to the Re-
public of Dantzic, and F. R. S. N° 467, p- 384. From the Latin.

This paper relates chiefly to a kind of antique, copper bracelet, dug up in
Prussia, and supposed to have been buried with its owner, some noble person-
age. It consists of twisted elastic copper wire, coiled into the form of a heli-
cal spring, of about 7 coils or rounds.

This opinion is confirmed by the learned Bartholin, who gives a figure of a
bracelet, composed of several rings connected together, from the museum of
Olaus Wormius; and calls it a monument of stupendous antiquity, worthy the
memory of posterity.

On account of affinity with the bracelet, M. Klein adds a silver ring, found
about a year before in a Prussian urn. It had threads twisted together in like
manner, to form the jewel ; the rest running out into two ends, not joined,
but only lying close together, and forming a circle ; so that it would, by its
elasticity, fit either a larger or smaller finger.

Observations and Experiments ivith Madder-Root, which has the Property of
tinging the Bones of living Animals of a red Colour. By M. Du Hamel du
Monceau,* F. R. S. &c. N" 457, p. 3Q0.

The fact of the bones of hogs and fowls coloured very red, by feeding on

• Henry Louis du Hamel du Monceau may be numbered aniong the most active and useful mem-
bers of the French Academy of Sciences during the 18th century. The subjects to which he par-
ticularly directed his attention were, 1. Agriculture; including the cultivation of trees, the manage-
ment of forests, and the preservation of timber; the preservation of com, &c. 2. The Arts, in the
descriptions of which, published under the superintendence of the Parisian Academy of Sciences,
and illustrated by an expensive set of engravings, he bore the principal part. 3. Naval Architecture
and the fisheries, with other matters relative to the marine, of which he was inspector. He died
in 1782, aged 82. His treatises on the various subjects abovementioned, amount to a great number
of volumes, most of them adorned with plates.


food mixed with the juices of madder-root, as related in the Philos. Trans.
N° 442 and 443, having been communicated to the Royal Acad, of Sciences at
Paris, M. Du Hamel du Monceau undertook to make a variety of experiments
of the same nature, which he did with the same effect, on many animals.

This however it seems is not a new discovery ; for Mizaldus, in a work pub-
lished in J 566, with this title, Memorabilium, utilium ac jucundorum Cen-
turiae novem. Cent. 7> has these words : ** Erythrodanum, vulgo Hubia tinc-
torum dictum, ossa pecudum rubenti et sandycino colore imbuit, si dies aliquot
illud depastae sint oves, etiam intacta radice, quae rutila existit, &c."

First, M. Du H. took 4 strong pullets, which he shut up in coops; and
fed them with a paste made of wheat-meal and powder of madder-root ; and
gave them an infusion of the same root to drink. The first days they eat
their paste pretty well ; but afterwards disliked it much, and eat always less
and less. As to the infusion of the rubia tinctorum, they never would drink
it, and he was obliged to give them pure water, which they drank plentifullv ;
for this root made them thirsty. At the end of some days they could not
relish the mixture, of which they eat but very little, and wasted away visibly.

On the lOth day, one of them died; and another 2 days after: and both of
them had their bones tinged of a rose-colour. To prolong the lives of the
other two, he diminished the dose of the madder, and sometimes he gave them
the paste without it. The root had already produced its effect ; for notwith-
standing the new regimen, they continued to waste; which obliged him to kill
the third 5 days after the death of the first 2. The colour of its bones was not
different from that of the 2, which died 5 days before. As to the 4th pullet,
which seemed not quite so sick, he set it at liberty. It recovered by degrees,
by choosing food to its taste in the yard. But at the same time the tincture its
bones had received, went off gradually, and almost entirely disappeared in a
month's time.

He next chose some strong young pigeons. Two of these had no other
food given them but wheat-meal, others were fed with the meal and madder
mixed and made into pellets, of a convenient size, given them 3 times a day
till their crops were full. But they could never be made to drink the infusion
of the madder. The two young pigeons fed with the meal alone were lively
and fat, digested their food, and throve as well as if fed by the old ones. But
on the contrary, those that were fed with the paste of meal and madder, took
this food only by force, digested ill, were dull and very thirsty. And though
care was taken to keep their crops constantly full, as well as the others, yet
they grew leaner daily. They were always shivering, and endeavouring to get
into the sun, or near the fire, to warm themselves : and the strongest of them


was very sick by the lOth clay, and the bones of their wings were already turned
red. By a change of diet however, the red colour gradually decreased and

All these creatures, that had been fed with the mixture, were dissected ;
and the following observations made on them. Neither the feathers, the horn
of the bill, nor claws, had changed their colour, even where they are inserted
into the skin. The skin of the whole body had preserved its natural colour.
The brain, nerves, muscles, tendons, cartilages, epiphyses, and membranes,
showed nothing contrary to the usual state of these parts. But the long bony
tendons, that run along the great bone, which is improperly called the leg of
fowls, were red about the middle of their length, which is their hardest part.
All the true bones, even to the very thinnest of them, were as red as carmine;
and in some places this red was so deep, that they appeared almost black.

In these young birds, all the bones do not take the red tinge alike. The
hardest are generally more coloured than those that are tenderer. A difference
of this kind is perceivable even in the same bone ; for the middle, which has
more solidity than the ends, is almost always the reddest. Not but there are
sometimes found little pale spots in the part where the red is deepest; and
sometimes spots of a very deep red in those parts which have taken but a car-
nation tinge.

The great bone of the foot, which is commonly called the bone of the leg,
was visibly less red than the others. The little bones of the larynx and of the
apophyses tinged of a fine red; though these are as small as a thread in young
pigeons. The rings of the trachea, which are entirely cartilaginous, had not
taken the least tinge; but the ring nearest the division of the trachea was red
in these pigeons; and even the first ring of each branch of the bifurcation
had in several taken the tincture, in the middle at least of its outside.

There was nothing remarkable in the thorax or the viscera; but the inner
membrane of the crop and intestines, especially the large ones, appeared red.
Having washed pieces of these crops and intestines, their outer membrane
continued white, and the inner, or tunica villosa, only was tinged by the
madder. At first sight it appeared as if injected; but on examining it with a
glass, it distinctly appeared, that it was not a coloured liquor that was contained
in vessels, as in parts injected; but that it was only a sort of faecula detained in
the villose part of these membranes. It is doubtless the adhesion of these
tinging particles of the root to the small villi of the inner membranes of the
organs of digestion, that is the source of all the distempers with which these
creatures appeared to be seized, while fed with the madder. Their crop espe-
cially was relaxed and flabby, as if it had been macerated several months in


water; it was easily torn, and its inner or villose metrtbrane adhered so little to
the others, that it was detached from them in pieces. A certain quantity of
this fascula, being accumulated there, retarded digestion, and those animals
died hectic, though with a full stomach.

The eyes of these animals, while alive, seemed as red as those of some parrots.
The capsula of the crystalline, and that of the vitreous humour, were of a
crimson red, though neither the vitreous humour nor the crystalline were dyed.

The tinged bones being broken, while fresh, or before drying in the air,
seemed somewhat larger and fuller of marrow; but also more spongy, or of a
looser texture, and easier to break, than the white bones of the pigeons fed
with meal only. The parts of these bones that had the least degree of hard-
ness, broke between the fingers, which remained coloured from them ; and this
tincture does not come from the marrow, which continues in its natural state,
like all the other soft parts. The same parts in the white bones were not to be
broken in this manner.

On viewing these bones with a good glass, their smoothest surface appears
bored with a vast number of small holes, in which the colouring faecula is per-
ceived. And with a microscope that magnifies still more, there appears a sort
of net- work of fibres, which divide, and reunite, to form this net. Under
the first order of this net-work, which appears white, another is seen some-
what red, and under this a third and a fourth, still deeper coloured ; in fine,
the ground under all these reticular strata is of a very deep red; and the whole
may be justly enough compared to a piece of wood stripped of its bark.

In other experiments, some young pigeons, fed with the paste mixed with
madder, died the third day ; yet all that had the consistence of bone in their
skeletons, was become as red as scarlet. Mr. Belchier was surprised to see the
bones of his cock tinged red in 1 6 days, yet here are bones so coloured in 3 days.
But all that should in course of time have turned to bone in one of the young
pigeons, and as yet was but cartilage, as the epiphyses, the great apophysis of
the sternum, &c. had not taken the least colour. In the other, there were some
spots of a very weak red on the cartilage of the sternum, which probably began
to ossify. Other experiments, since tried, have taught with greater certainty,
that the cartilages in general are not tinged red by the madder, except when
they begin to acquire the consistence of bone.

It appears that the bones of animals that are still growing, are dyed better
and quicker than those of full- grown animals. Two turkeys had the same
ailments with the pullets of the first experiment, they fell into a decay like
those, and they were obliged to be killed in 15 days.

Here we see young pigeons, whose bones were dyed of a fine carmine-red


in 3 days, which is nearly the time they must have for acquiring this degree of
tincture. By other experiments on young pigeons of the same age, in 36
hours their bones were of a lively rose-colour, and in 24 hours they were at
least of a flesh-colour.

These last experiments prove with what expedition the distribution of the
nutritious juice is performed in animals of this kind, which acquire all their
growth in a few months; and how rapid the distribution is, even in those parts
where the blood's circulation meets with the greatest obstacle, as in the sub-
stance of the bones.

The rubia probably is not the only vegetable substance that can change the
colour of the bones; and yet the log-wood, the anchusa and curcuma, have
been tried without success. Probably it must be a substance less susceptible of
alteration; and it is well known, tliat the rubia is of that sort, seeing that
clothes dyed with this root bear very well the action of the air, and of boiling.

M. du H. put the coloured bones of the animals to several proofs; first, as
Mr. Belchier, to that of boiling water, and of spirit of wine, without the least
change of colour. It also resisted soap-suds. A strong lixivium of salt of
tartar discharged a little of the colour, and made it look brighter. Vinegar
made it take a yellowish brown and obscure tinge. In fine, alum-water dis-
charged the colour pretty considerably, and the water remained somewhat
vinous. Thus these bones perfectly well resist the same boilings as the clothes
dyed with the same root; but the air acts on them much sooner than on these
clothes; for the bones of the pullets in the first experiment, those of the turkeys
in a third, and those of the young pigeons, that had eaten of the madder but 3
days, became entirely white in less than a year, and the reddest bones lost much
of their colour. And he thinks, that the dew, to which he exposed some of
them for a few days, will finish the blanching of them.

yi Catalogue of fifty Plants from Chelsea Garden, presented to the Royal Society
by the Company of Apothecaries, for the Year 1739, pursuant to the Direc-
tion of Sir Hans Sloane, Bart. By Isaac Rand, F. R. S. N" 457, p- 406.

This is the 18th presentation of this kind, completing the number of 900
different kinds of plants.

A Physico-mathematical Demonstration of the Impossibility and Insufficiency of
Vortices. By M. de Sigorgne. N° 457, p- ^OQ.

M. de S. here takes great pains to refute the existence, and even the possi-
bility of the Cartesian vortices. He undertakes to prove, 1 . That the mecha-


nical formation of a vortex is impossible ; 2. That a vortex, though once formed,
cannot be lasting ; 3. That it is not sufficient for explaining the celestial phaeno-
mena. After labouring these points, at great length, in the details of which it

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 49 of 85)