DEN 
near it are remarkable and magnificent ruins, fuppofed 
of an ancient temple of Serapis. Mr. Browne, who palled 
through this place in October 1792, defcribes the temple 
as the moll perfect remain of Egyptian architecture It is 
in the form of an oblong fquare, 200 feet by 150. Many 
of the mafiive columns are yet (landing. The infide of 
the prcnaos, and of the gallery, is covered with painted 
hieroglyphics in all their original frefhnefs : 242 miles 
loirth of Cairo, and forty eight fouth-fouth-ealt of Girge. 
DENDERBEL'LE, a town of Flanders: one league 
fouth of Dendermond. 
DENDERMO'ND, or Termond, a town of Flanders, 
fituated at the union of the Dender and Scheldt, in a 
very fertile country, and furrounded with meadows well 
watered by thofe two rivers, and which, by means of 
fluices, will in a fhort time produce water enough to in¬ 
undate all the neighbouring country. It has two pa¬ 
rties, aud feveral religious houfes. In 1667, LouisXIV. 
attempted to make himfelf mafter of this place, but was 
obliged to retire with precipitation, to prevent his army 
of 50,000 men being dedroyed, the inhabitants having 
begun to open the lluices. In 1706, general Churchill 
befieged it; it had been a long time blockaded, but be¬ 
ing a very dry feafon, the befiegers found means to drain 
off the water, attacked the city, and compelled it to fub- 
mit, the 15th of September, (lx days after tire trendies 
had been opened ; the garrifon, with the governor, the 
marquis del Valle, furrendered prifoners of war. The 
Dutch put in a garrifon of their troops, till the year 
1715, when it was agreed with his imperial and catholic 
majefty, by the barrier treaty, that for the future the 
Dutch fiiould furniih one part of the garrifon, and that 
the other part fiiould be of imperial troops, or of tiie 
country ; and that the governor fiiould be appointed by 
the emperor, taking an oath of fidelity to the dates ge¬ 
neral ; fourteen miles ead of Ghent, and feventeen north- 
wed of Brudels. Lat. 51.T.N. Ion. 21. 39. E. Ferro. 
DENDERWYN'DEKE, a town of Flanders: one 
league fouth of Ninove., 
DENDRACHA'TES, f. [from a tree ; and 
the agate. ] A fpecies of agate-done, with drealts 
in it refembling the branches of trees. 
DEN'DRITES, f. in natural hidory, a kind of done, 
the veins of which appear like trees. 
DENDRO'LOGY,/. [of kvfyoV, a tree ; and *070?, of 
Myu, Gr. to fay or treat.] A treatife or difeourfe on 
trees ; the natural hidory of trees. 
DENDRO'METF.R, f. An indrument invented by 
Mefiirs. Duncombe and Whittel; fo called, from its ufe 
in meafuring trees. The fame name has been recently 
given, by William Pitt, efq. of Pendeford, near Wolver¬ 
hampton, to an indrument propofed by him for meafur¬ 
ing didances by one obfervation. To accomplilh this 
purpofe two methods may be propofed, founded on dif¬ 
ferent principles ; the one on the fuppofition of the ob- 
ferver being in the center, and the objedt in the circum¬ 
ference, of a circle ; the other, on the contrary fuppofi¬ 
tion, of the obferver being in the circumference, and the 
objedt in the center. To determine the didance of any 
objedt on the fird fuppofition, the bulk or dimenfions of 
fuch objedt mud be known, either by meafure or eftima- 
tion, and the angle formed by lines drawn to its extre¬ 
mities being taken by an accurate indrument, the didance 
is eafily calculated. This new method of meafuring dif- 
ta.nces, the author illudrates by the following example : 
Suppofe A, fig. x. in the following diagram, the place 
of the indrument ; B C an afliftant’s dad, with a perpen¬ 
dicular pin at D, to enable the aflidant to hold it in its 
right pofition; now, if the angle BAG could, by the 
help of a micrometer, be afeertained to parts of a minute, 
the didance from A to B, or to C, might be eafily cal¬ 
culated by the rules of plain trigonometry. But this 
Method of afeertaining didances cannot be applied to 
macceflible objects, and it is moreover fubjedt to the in- 
«onvenience of an adiftant being obliged to go to the ob- 
D E N 719 
jedt whofe didance is required, (an inconvenience almod 
equal to. the trouble of adtual admeafurement;) there¬ 
fore the perfedtion of the feepnd method propofed is 
principally ;o be defired ; namely, that of conceiving the 
obfervation made on the circumference of a circle, whofe 
center is in the objedt whofe didance is to be afeertain¬ 
ed ; and, none of our indruments now in ufe being adapts 
ed to this mode of obfervation, the following principles 
of condrudtion are propofed, which may, perhaps, be 
further varied and improved. O, fig. 2. the objedt of 
whofe didance is required ; ABCDE the indrument in 
piano ; BC a telefcope, placed exadtly parallel to the 
fide A E ; C E an arch of a circle, whofe center is at A, 
accurately divided from E in degrees, &c. A D an index, 
moveable on the center A, with a nonius fcale at the end 
D/graduated to apply to the divifions of the arch; alfo 
with a telefcope, to enable the obferver to dilcriminate 
the objedt, or any particular part or fide thereof, the 
more accurately. The whole fiiould be mounted on three 
legs, in the manner of a plain table, or theodolite, and 
furnifhed with fpirit tubes to adjud it to an horizontal 
pofition. The indrument being placed in fuch pofition, 
the telefcope BC mud be brought upon the objedt O, 
or rather upon fome particular point or lide thereof; 
when, being there fadened, the index A D mud be moved 
till its telefcope exadtly drikes the fame point of the ob¬ 
ject; then the divifions on the arch ED mark out the 
angle DAE, which will be exadtly equal to the angle 
BOA, as is demondrated in the fifteenth and twenty- 
ninth propofitions of Euclid, book i. and the fide B A, as 
well as the angles ABO, and B A O, being already known, 
the didance BO, or AO, may be eafily determined. As 
the perfection of this indrument depends altogether upon 
its accuracy in taking fmall angles, fo that accuracy mud 
depend, not only upon the indruments being properly 
fitted with a micrometer, but alfo in fome meafure upon 
the length of the line B A in the figure. That line, there¬ 
fore, might be extended, by the indrument being cor- 
ftrudted to fold or Hide out to a greater length when in 
ufe ; upon which principle, connected with the applica¬ 
tion of a micrometer, an accurate and ufeful indrument 
might certainly be condrudted. To adjud fuch indru¬ 
ment for ufe, let a daff be held up at a didance, in the 
manner of fig. 1. exactly equal in length to the didance 
of the two telefcopes, and the index A D being brought 
exadtly upon the fide AE, if the tw r o telefcopes accu¬ 
rately drike either end of the daft', the indrument is pro¬ 
perly adjuufted. 
The condrudtion of a fimilar indrument, on the prin. 
ciples of Hadley’s quadrant, for naval obfervations, would 
alfo be an acceptable objedt in navigation, by enabling 
the mariner to afeertain the diftancqs of (hips, capes, and 
other objedts, at a fingle obfervation ; and that, perhaps, 
with greater accuracy than can be done by any method 
now in ufe. For this purpofe, the following condruc- 
tion is propofed; ABCDE, fig. 3, the indrument in 
plant ; 
