or NILOSCOPE, an instrument used among the ancients to measure the height of the water of the river Nile in its overflows.

The word comes from Νείλος, Nile (and that from νειλος, "new mud," or as some others would have it, from νευ, "I flow," and ιος, "mud,") and μέτρον, "measure." The Greeks more ordinarily call it, Ναλομετρεύσιον.

The nilometer is said, by several Arabian writers, to have been first set up, for this purpose, by Joseph during his regency in Egypt: the measure of it was 16 cubits, this being the height of the increase of the Nile, which was necessary to the fruitfulness of Egypt.

From the measure of this column, Dr Cumberland * Scripture deduces an argument, in order to prove that the Jewish and Egyptian cubits were of the same length.

In the French king's library is an Arabic treatise on nilometers, entitled Nil fī almal al Nil; wherein are described all the overflows of the Nile, from the first year of the Hegira to the 875th.

Herodotus mentions a column erected in a point of the island Delta, to serve as a nilometer; and there is still one of the same kind in a mosque of the same place.

As all the riches of Egypt arise from the inundations of the Nile, the inhabitants used to supplicate them at the hands of their Serapis; and committed the most execrable crimes, as actions, forsooth, of religion, to obtain the favour. This occasioned Constantine expressly NIM to prohibit these sacrifices, &c. and to order the nilometer to be removed into the church; whereas, till that time, it had been in the temple of Serapis. Julian the Apostate had it replaced in the temple, where it continued till the time of Theodosius the Great.

The following is Mr Bruce's account of the nilometer. "On the point of the island Rhode, between Geesza and Cairo, near the middle of the river, is a round tower enclosing a neat well or cistern lined with marble. The bottom of this well is on the same level with the bottom of the Nile, which has free access to it through a large opening like an embrasure. In the middle of the well rises a thin column of eight faces of blue and white marble; of which the foot is on the same plane with the bottom of the river. This pillar is divided into 20 pecks, of 22 inches each. Of these pecks the two lowermost are left, without any division, to stand for the quantity of fludge which the water deposits there. Two pecks are then divided, on the right hand, into 24 digits each; then on the left, four pecks are divided into 24 digits; then on the right, four; and on the left another four: again, four on the right, which completes the number of 18 pecks from the first division marked on the pillar, each peck being 22 inches. Thus the whole marked and unmarked amounts to something more than 36 feet English."

On the night of St John, when, by the falling of the dew, they perceive the rain water from Ethiopia mixed with the Nile at Cairo, they begin to announce the elevation of the river, having then five pecks of water marked on the nilometer, and two unmarked for the fludge, of which they take no notice. Their first proclamation, supposing the Nile to have risen 12 digits, is 12 from 6, or it wants 12 digits to be 6 pecks. When it has risen three more, it is nine from fix; and so on, till the whole 18 be filled, when all the land of Egypt is fit for cultivation. Several canals are then opened, which convey the water into the desert, and hinder any further stagnation on the fields. There is indeed a great deal of more water to come from Ethiopia; but were the inundation suffered to go on, it would not drain soon enough to fit the land for tillage: and to guard against this mischief is the principal use of the nilometer, though the Turkish government makes it an engine of taxation. From time immemorial the Egyptians paid, as tribute to the king, a certain proportion of the fruit of the ground; and this was anciently ascertained by the elevation of the water on the nilometer, and by the mensuration of the land actually overflowed. But the Saracen government, and afterwards the Turkish, has taxed the people by the elevation alone of the water, without attending to its course over the country, or the extent of the land actually overflowed; and this tax is sometimes cruelly oppreive.