Thermometers have hitherto been defective for meteorological purposes, in so far as they only point out the degree of heat at the moment of inspecting them, but do not show what the difference of temperature has been, from the time of one observation to that of another: Nor has any instrument been yet constructed, so far as I have been able to learn, which will record the intermediate degrees of heat.

The ingenious Robert Hook, in the end of the last century, mentions his intention of making a thermometer for the above purpose ; but it does not appear that it was ever executed: Neither does he explain how it was to have been done.

In August last, I read to this Society the Description of an Air Thermometer intended to record the various degrees of heat at every instant; and mentioned my intention of constructing a barometer, which would, in the same manner, record the variations of the weight of the atmosphere: Both which I proposed to adapt to one piece of clock-work.

This piece of machinery appearing too complicated and expensive for general use, I contrived a thermometer, which marks the extreme points of heat and cold from any two times of observation. Of which instrument I also lately read an account, and produced the machine itself.

The life of which I am about to give some account to this Society cannot be called a literary one; of literary lives only it is perhaps the proper business of the Royal Society to record the particulars; but it has been in the practice of allowing a wider range to this customary notice of its deceased Members. Of the lives of such as were eminent in station or in usefulness, in abilities or in virtue, it has been accustomed to hear a narrative, which, though not important to learning, is interesting to humanity. Under this title, it will indulge me with a short account of the life of Lord Abercromby.

The Journal of the Weather, of which an abstract is here communicated, has been kept in a house in Windmill Street, on the south side of Edinburgh. The latitude of Edinburgh College, as deduced from a series of astronomical observations made at Hawkhill, is 55° · 57ʹ · 5″ nearly. Windmill Street is about 500 yards farther to the fouth.

The barometer used in these observations is a portable one, of the construction invented by Dr Lind, physician at Windsor; the mercury was boiled in the tube, and the scale is divided into the five-hundredth parts of an inch. The place where it stands is 265 feet above the level of the sea, or of the mean high-water mark at Leith. The height of it is marked every morning at 10 o'clock, as well as that of a thermometer, in the same room, which gives the temperature of the mercury.

The custom which this Society has established, of giving some account of the lives of its deceased members, is in every case gratifying to friendship, in many interesting to curiosity, but in those which serve to record the pursuits and occupations of men of letters, it is more strictly and properly an object coming within the views of a literary institution. The history of the authors is always in a great degree the history of the literature of a country; and even exclusive of an immediate relation to their works, the narrative of their private and domestic habits is often, in a moral point of view, useful and interesting to the scholar and the author. In both these respects, I may claim the attention of the Society to the following short account of the life and writings of our late worthy colleague, Mr William Tytler.

In writing the life of a person who himself published nothing, it is extremely difficult to satisfy the expectation of his particular friends, without incurring the charge of adulation from the rest of the public. How far I have succeeded in doing justice to Mr Hamilton's merit, without insensibility or exaggeration, must be determined by those who knew him, and by those who can appreciate the worth of such professional remarks as I shall lay before them in the sequel. Mr William Hamilton was born in Glasgow July 31. 1758. Having finished the usual course at the Grammar School, he went to Glasgow College in 1770, and continued there studying with great diligence till 1775, when he became Master of Arts at the age of seventeen.

Long after the arts of ancient Greece and Rome had been lost, and before any effectual attempt was made to revive them, a style of building, known among us by the name of Gothic Architecture, began to appear in Europe.

At first, a few only of its peculiar forms were employed, which, in some old buildings, are to be met with, intermixed with the remains of a still more ancient style. Afterwards, rising by degrees into favour, it supplanted, in all the departments of architecture, every other species of design, and maintained an unrivalled dominion during three hundred years.

Doctor John Roebuck was born at Sheffield in Yorkshire, in the year 1718. His father was a considerable manufacturer and exporter of Sheffield goods, who, by his abilities and industry, had acquired a competent fortune. John, his eldest son, the subject of this memoir, was intended, by his father, for carrying on his own lucrative business at Sheffield; but was, from his early youth, irresistably attached to other pursuits, more calculated to gratify his ambition, and give fuller play to his powers. Notwithstanding this disappointment in his favourite object, his father had liberality enough to encourage his rising genius, and to give him all the advantages of a regular education.

As the Members of this Society afforded to M. Chevalier an early and warm encouragement and patronage, and readily gave his Tableau de la Plaine de Troye a place in their Transactions, as well as admitted the author to a seat among their number; and as that paper, since the time of its publication, has excited a good deal of interest and speculation, they will, no doubt, hear with pleasure, that it has now received, at least in all its material circumstances, a most ample and satisfactory confirmation.