observer draws away the movable part, which readily rolls on a railway. The extremity of the telescope bearing the mirror of the objective is thus left uncovered, while the astronomer, ensconced in his fixed part as in his own room, and sheltered from all inclemencies of weather, studies the infinitely great in conditions as comfortable as those of the naturalist who examines under his microscope the infinitely little.

Seeing it is but just that those who bear the burden should also enjoy the honour, we again state that the optical part of this instrument has been executed by the Brothers Henry, and the mechanical part by MM. Eichens and Gauthier.

THE INSTITUTION OF MECHANICAL
ENGINEERS

THE
HE Institution of Mechanical Engineers have held
their autumn meeting this year in Birmingham-a
town which for many years was the headquarters of the
Society. The returning to their former seat was specially
opportune, because the first paper on the list related to
one of the greatest of Birmingham worthies, viz. James
Watt. The title of the paper was 66
On the Inventions of
James Watt, and his Models preserved at South Kensing-
and Handsworth." The author is Mr. Edward A. Cowper,
who, from his long connection with engineering both per-
sonally and through his father and uncle, is perhaps as
well fitted as any man in England to trace out the course
of Watt's inventions. This he has endeavoured to do,
using as his main guide the numerous models preserved
partly at the South Kensington Museum, partly at the
Patent Office Museum, and partly at James Watt's house
at Handsworth in Birmingham. Some of the models at
South Kensington were in danger of falling altogether to
pieces from dry rot and decay, but owing to the exertions
of Mr. Sandham, the curator of this department, they
have, as far as possible, been repaired; whilst, in addi-
tion, a complete set of photographs has been taken,
which, even if the models themselves should cease to
exist, would preserve their appearance and construction
to future ages.

The sequence of James Watt's inventions with regard to the steam engine is stated at the end of Mr. Cowper's paper as follows:

Firstly, in 1769 he made an invention (the separate condenser) which was practically an improvement on the Newcomen engine, the effect of which was to work pumping engines more economically and quickly.

Secondly, in 1781 he produced rotative power for driving factories, obtaining it in a manner by having a heavy balance weight to act one way whilst the steam acted the other way; however, the obtaining rotative motion by steam was an enormous advantage, far greater in its effect, in the author's opinion, than the improvement in the pumping engine.

Thirdly, the crowning invention of 1782 made the steam engine the one useful motive power, by making it double-acting and fit to drive cotton mills, flour mills, and all other machinery requiring regular rotative motion.

These various stages are illustrated by the models above mentioned. It is indeed doubtful whether there exists at present any model embodying the first idea of the separate condenser; but there is a most interesting model at South Kensington showing the condensation of steam in a separate surface condenser, composed of a large number of vertical tubes and provided with an air pump. This form of condenser, which in many cases, such as marine engines, has superseded all others, is thus proved to have been invented by James Watt, and not only invented, but brought to a high degree of perfection. The arrangements in this model, according to Mr. Cowper (than whom there can be no better authority), are in

points equal to the best modern examples of surface condensation.

The only model actually exhibited was an engine of the character of Watt's patent of 1771. It is single acting, and has an open-topped cylinder, air pump, and condenser. There is a heavy bob on the connecting rod, which is used to help the piston up, while the vacuum formed below it causes it to descend on the return stroke, thus obtaining rotative motion. This engine, however, has a crank, and it is known that for many years Watt was afraid to use the crank in his engines, as it was supposed to be barred by another patent: it is true that his patent of 1771 shows a crank composed of a pin in a disk, but this is carefully termed "the point of attachment of the connecting rod." In practice, however, he used other methods, chiefly the well known sun and planet motion. Of this there are several different forms, which are illustrated by models at South Kensington. There is also a device consisting of a long rack or ladder fixed to the end of the connecting rod and digging into the teeth of a spur wheel on the engine shaft; the rod being guided by means of rollers running in a guide plate, so as to keep it in gear throughout the revolution. Turning now to the 1782 patent, we find what Watt describes as "the new improved engine, the piston of which is pressed forcibly both upwards and downwards by the power of steam," that is to say, the engine is no longer single-acting, but double-acting. Here the chain hitherto used between the piston-rod and beam is replaced by a parallel motion, and the engine takes very much the form which was still common for shop engines within recent years. A good model of such an engine exists in the South Kensington Museum.

Some variations of this engine, probably made subsequently, are also illustrated by models, such as the Bull engine, in which the piston-rod passes out through the bottom of the cylinder, and takes hold of a beam placed lower down.

Still more interesting are Watt's proposals to make use of the expansion of steam for the saving of fuel; a diagram in one of his specifications shows that he fully understood this action, and he gives several methods by which the load upon the piston may be varied so that when the pressure is least it shall have least work to do. One of these is to mount a weight high up above the beam, which would be lifted when starting from either end of the stroke, and fall after passing the centre; this has been used even in recent times with good results. Several miscellaneous inventions of high interest are also described; one of these is the well-known invention of the steam indicator in probably its earliest and rudest form. Another is a counter for telling the revolutions of an engine, of which an actual specimen in good preservation remains in the Patent Office Museum.

There is also an arangement for obtaining rotary motion in opposite directions out of the same engine by means of two connecting rods starting from a cross-head at one end of the beam, but working opposite ways. Another model shows two hammers worked by a single engine, the one lifted from the belly like an ordinary forge hammer, and the other by depressing the tail like a tilt hammer. A yet more curious device is a semi-rotary engine, of which an unfinished model remains in the Watt Room at Heathfield Hall. Here there is a piston fixed in a radial line to the shaft, within a large disk or cylinder. Inside this cylinder, at one part, is a fixed support, against which the steam presses each way as it acts against the piston, in either one direction or the other. The reciprocating shaft was made to act by a spur wheel on two racks attached to the pump rods. Watt also invented a very simple form of rotary engine, which, as Mr. Cowper states, has probably been reinvented at least fifty times since 1782, the year of his patent.

that of the ridges on the border of the glaciers, as well as in equal quantity on the top of the ice-knolls as on their sides or in the hollows between them.

2. That neither had it been distributed over the surface of the ice by running water, nor been pressed up from the hypothetical bottom "ground" moraine.

3. That the clay must therefore be a sediment from the air, the chief constituent of which is probably terrestrial dust spread by the wind over the surface of the ice.

4. That cosmic elements exist in this substance, as it contained molecules of metallic iron which could be drawn out by the magnet, and which under the blowpipe gave a reaction of cobalt and nickel.

Under these circumstances the remarkable dust which I have named "kryokonite," i.e. ice dust, obtained a great scientific interest, particularly as the cosmic element, viz. the matter deposited from space, was very considerable. Even later students who have visited the inland ice have observed this dust, but in places surrounded by mountains from which it might with more probability have been washed down. They have, therefore, and without having examined Prof. Berggren's and my own researches of 1870, paid little attention to the same, while the samples brought home by Dr. N. O. Holst from South Greenland in 1880 were not very extensive.

But now Dr. Berlin brings home from a great variety of places ice algæ, which, I feel convinced, will contribute fresh materials to our knowledge of the flora of the ice and snow. For my own part I have re-examined my first researches of the kryokonite, and they are fully corroborated. Everywhere where the snow from last winter has melted away, a fine dust, gray in colour, and, when wet, black or dark brown, is distributed over the inland ice in a layer which I should estimate at from o'i to I mm. in thickness if it was evenly distributed over the entire surface of the ice. It appears in the same quantity in the vicinity of the ice border surrounded by mountains as a hundred kilometres inland, but in the former locality it is mixed with a very fine sand, gray in colour, which may be separated from the kryokonite. Further inland this disappears, however, completely. Gravel or real

sand I have never, in spite of searching for them, discovered in the kryokonite. The kryokonite always contains very fine granular atoms, which are attracted by the magnet, and which, as may be demonstrated by grating in an agate mortar and by analysis under the blowpipe, consist of a gray, metallic element, viz. nickel iron In general the dust is spread equally over the entire surface of the ice; thus it was found everywhere where the snow from the previous year had melted away, while, to judge by appearances, there seemed to be little difference between the quantity found near the coast and in the interior. The dust does not, however, form a continuous layer of clay, but has, by the melting of the ice, collected in cavities filled with water, which are found all over the surface. These are round, sometimes semicircular, one to three feet in depth, with a diameter of from a couple of millimetres to one metre or more. At the bottom a layer of kryokonite one to four millimetres in thickness is deposited, which has often, by organisms and by the wind, been formed into little balls, and everywhere where the original surface of the ice has not been changed by water-currents the cavities are found so close to each other that it would be very difficult to find a spot on the ice as large as the crown of a hat free froin them. In the night, at a few degrees below freezing point, new ice forms on these hollows, but they do not freeze to the bottom even under the severest frost, and the sheet which covers them is never strong enough to support a man, more particularly if the hole is, as was the case during half our journey, covered with a few inches of newly-fallen snow.

The kryokonite cavities were perhaps more dangerous to our expedition than anything else we were exposed to. We passed, of course, a number of crevasses without

bottom as far as the eye could penetrate, and wide enough to swallow up a man, but they were open," i.e. free from a cover of snow, and could with proper caution be avoided, and the danger of these could further be minimised by the sending of the two-men sledges in front, and if one of the men fell into the crevasse he was supported by the runners and the alpenstock, which always enabled him to get up on the ice again. But this was far from being the case with the kryokonite hollows. These lie, with a diameter just large enough to hold the foot, as close to one another as the stumps of the trees in a felled forest, and it was therefore impossible not to stumble into them at every moment, which was the more annoying as it happened just when the foot was stretched for a step forward, and the traveller was precipitated to the ground, with his foot fastened in a hole three feet in depth. The worst part of our journey was four days outward and three days of the return, and it is not too much to say that each one of us during these seven days fell a hundred times into these cavities, viz. for all of us 7000 times. I am only surprised that no bones were broken, an accident which would not only have brought my exploration to an abrupt close, but might have had the most disastrous consequences, as it would have been utterly impossible to have carried a man in that state back to the coast. One advantage the kryokonite cavities had, however, viz. of offering us the purest drinking-water imaginable, of which we fully availed ourselves without the least bad consequences, in spite of our perspiring

state.

On July 16 we covered thirteen, on the 17th eighteen and a half, and on the 18th seventeen and a half kilometres. The country, or more correctly the ice, now gradually rose from 965 to 1213 metres. The distances enumerated show that the ice became more smooth; but the road was still impeded by the kryokonite cavities, whereas the rivers, which even here were rich in water, became shallower, but stronger, thus easier of crossing. Our road was, besides, often cut off by immense snow-covered crevasses, which, however, did not cause much trouble.

On the night of the 18th, when arrived at camp No. 14, the Lapp Anders came to me and asked if he might be permitted to "have a run," viz. to make a reconnaissance on "skidor," to see if there was no "land" to the east. This granted, he started off without awaiting supper. He came back after six hours' absence, and reported that he had reached 27 kilometres further east, that the ice became smoother, but was still rising, but there was no sign of "land." If his statement was true, he had, after a laborious day's journey, in six hours covered about sixty kilometres! At first I considered his estimate exaggerated, but it proved to be perfectly correct. It took us thus two whole days to reach as far as he had got, as shown by the track in the snow. I particularly mention this occurrence in order to show that the Lapps really did cover the estimated distance of their journey eastward, of which more below.

During these days we passed several lakes, some of which had the appearance of not flowing away in the winter, as we found here large ice blocks several feet in diameter, screwed up on the shore, which circumstance I could only explain by assuming that a large quantity of water still remained here when the pools about became covered with new ice. The lakes are mostly circular, and their shores formed a snow "bog" which was almost impassable with the heavy sledges.

On July 19 we covered seventeen and a half, on the 20th sixteen and a half, on the 21st, seven, and on the 22nd seven and a half kilometres (15th to 18th camp). The ice rose between them from 1213 to 1492

[The Swedish "skidor" and Norwegian "Ski," are long strips of pinewood slightly bent at the top, polished and as elastic as if they were of the finest steel, with a strap for the feet in the centre, on which the Lapps and Scandinavians run on the snow with remarkahle agility at a tremendous pace.-ED.]

metres. The distances enumerated fully show the nature of the ice. It was at first excellent, particularly in the morning, when the new snow was covered with a layer of hard ice; but on the latter days we had great difficulty in proceeding, as a sleet fell with a south-east wind in the night between the 20th and the 21st. The new snow, as well as that lying from the previous year, became a perfect snow bog in which the sledges constantly stuck so that it required at times four men to get them out. We all got wet, and had great difficulty in finding a spot on the ice dry enough to pitch the tent. On the 22nd we had to pitch it in the wet snow, where the feet immediately became saturated on putting them outside the indiarubber mattresses. A little later on in the year, when the surface of the snow is again covered with ice, or earlier, before the thaw sets in, the surface would no doubt be excellent to journey on.

When we, therefore, on July 21, were compelled to pitch the tent in wet snow, as no dry spot could be discovered, and it was impossible to drag the sledges further, I sent the Lapp Lars Tuorda forward on "skidor" to find a dry road. He came back and stated that the ice everywhere was covered with water and snow. For the first time in his life he was at a loss what to suggest. It being utterly impossible to get the sledges further, I had no choice. I decided to turn back.

I wished, however, to let the Lapps go forward some distance to the east to see the country as far as possible. At first I considered it advisable to let their journey only last twenty-four hours, but as both Anders and Lars insisted that they were most eager to find the "Promised Land," and said they could do nothing towards discovering it in that short period, I granted them leave to run eastwards for four days and nights, and then return. On leaving I gave them the following written orders :"Instructions for Lars and Anders's 'skid' run on the inland ice of Greenland, viz. :

66

Lars and Anders have orders to proceed on skidor eastwards, but are allowed to alter the course, if they may deem it advisable, to north or south.

"At the end of every third mile the barometer shall be read and the direction run noted.

"The absence is to be four days, but we will wait for six days. After that, viz. on the morning of July 28, we return. If not returned, we leave behind in a sledge provisions, brandy, mattresses, &c.

"Lars is warned not to be too bold. Should land be reached, you are to collect as much as you may gather of

blossoms and grass, if possible several kinds (specimens)

of each.

"Given on the inland ice in Greenland, July 21, 1883, "A. E. NORDENSKJÖLD"

They were allowed to select what provisions, &c., they desired, and were furnished with two compasses, aneroid barometers, and a watch.

At 2.30 a.m. on July 22 they started. The days we waited for them were generally spent in the tent, as water surrounded us everywhere. The sky was covered with a thin veil of clouds, through which the sun shone warmly, at times even scorchingly. From time to time this veil of clouds, or haze, descended to the surface of the ice and hid the view over the expanse, but it was, remarkably enough, not wet but dry, yes, so dry that our wet clothes absolutely dried in it. We have therefore, I consider, witnessed a phenomenon on the inland ice of Greenland which is related to the "sun-smoke" phenomenon of Scandinavia, viz. what Arago has described under the name 66 'brouillard sec."

On the 24th, after an absence of fifty-seven hours, the Lapps returned. It was the want of drinkingwater and fuel which compelled them to return. The surface had been excellent for their journey, and they had covered a distance out and back of 230 kilometres, an

estimate which I consider perfectly reliable. During the march forward the barometer was read every third hour. It gave the point of return a height of 2000 metres.1 As to the run, Lars rendered the following report: When they had reached thirty miles from the camp no more water could be found. Further on the ice became perfectly smooth. The thermometer registered -5° C. It was very easy to proceed on the "skidor." At the point of return the snow was level and packed by the wind. There was no trace of land. They only saw before them a smooth ice covered by fine and hard snow. The composition of the surface was this-first four feet of loose snow, then granular ice, and at last an open space large enough to hold an outstretched hand. It was surrounded by angular bits of ice (crystals). The inland ice was formed in terraces-thus, first a hill, then a level, again another hill, and so on. The Lapps had slept for four hours, from twelve midnight on July 23, in a hollow dug in the snow while a terrific storm blew. They had till then been awake for fifty-three hours. On the first day there was no wind, but next day it came from the south, and lasted thus until twenty-four miles on the return journey, when it changed to west. On the return journey, when forty miles from our camp, two ravens were seen. They came from the north and returned in the same direction. The Lapps had for a moment lost the track of the "skidor" in the snow. The ravens flew at first, they found, parallel with the track, and then turned to the north.

On July 25 we began the return journey. It was high time, as the weather now became very bad, and it was with great difficulty we proceeded in the hazy air between the number of crevasses. The cold, after the sun sunk below the horizon at night, also became very great; and on the morning of July 27 the glass fell to -11° C.

As to the return journey I may be very brief. The rivers now impeded us but little, as they were to a great extent dried up. The ice-knolls had decreased considerably in size too, and lay more apart, but the glacial crevasses had greatly expanded, and were more dangerous, Even the cavities and the being covered with snow. glacial wells, of which many undoubtedly leave a veritable testimony of their existence behind them in the shape of corresponding hollows in the rock beneath, had expanded and increased in number. On a few occasions, on the return journey, we saw flocks of birds, most probably water-fowl, which were returning from the north.

On July 31 we again sighted land, which was reached Harbour," where Esquimaux were, as arranged, waiting on the afternoon of August 4, and proceeded to "Sophia

for us. For convenience sake I now divided our party into two, one of which sailed in the lifeboat of the Sophia to Egedesminde, where the steamer was to take us on board, and the other, in which was myself, marched to that place across the low but broad promontory which separates Tessiusarsoak and South-East Bay, and then in two Esquimaux "Kone" boats to Ikamiut and Egedesminde. On August 16 the Sophia arrived from the north, embarked us, and made for Ivigtut, where we arrived on the 19th.

Of the expedition carried out under Dr. Nathorst during my absence he will himself make a report, and I have no doubt that the results of the same will prove very important. Particularly will the very rich collections of fossil plants, which he has made with the greatest regard to the geological condition of the strata, be of great value to science, as they will furnish us with many new materials and detailed illustrations of the flora of the Far North during the epoch when forests of fig-trees, cycadi, ginko, magnolia, and tulip-trees Dr. Forsstrand and Herr covered these regions.

I have as yet been unable to verify the barometer calculations, and the figures stated here may suffer some modification. 2NATURE, vol. xxviii. p. 541.