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ent this person's rubric is from the others. these well-known Spanish settlers have found How very forcibly this reminds one of one their way into the hands of collectors of autoof those old fashioned metal door-plates. It graphs, particularly those containing these is completely surrounded by graceful scal- peculiarly characteristic and interesting rulops. Without doubt this person must have brics. The reason is that the documents held quite a high opinion of himself, and de- thus inscribed formed a part of the governsired those who chanced to see him attach ment archives and did not fall into the hands the rubric to his signature or to observe it of private individuals. What a feast they afterward, to regard him as of someone of would all be for some of our expert graphimportance. Very few of the signatures of ologists to ponder over!
By permission of McClure's Magazine M. JANSSEN'S OBSERVATORY AT THE SUMMIT OF MONT-BLANC
BY EDWARD S. HOLDEN
HEN Galileo invented the might be better in the pure air of high
telescope in 1609 his only mountains. He says:
"If the theory of making telescopes could at length
be brought fully into practice, yet there would be cerpossible. When it was
tain bounds beyond which telescopes could not perperfect all the condi
form. For the air through which we look upon the tions of observation stars is in a perpetual tremor, as may be seen by were satisfactory. New
the twinkling of the fixed stars. The only remedy is ton (in 1717), whom nothing
a most serene and quiet air, such as may perhaps be
found on the tops of the highest mountains above the escaped, saw that vision
Sir Isaac Newton's statement is admir- air. Two conditions of good vision are imperable in its concise completeness. To under- atively required; a pure atmosphere, free stand the question of the advantage of from dust; and a quiet air permitting the mountain observatories we have simply to use of high magnifying powers. The latter interpret and expand his suggestions. The condition is far more important. Perhaps, air must be serene and pure; that is, free says Newton, perhaps these conditions may from the dust and smoke and vapors of the be found on the tops of the highest mounlower levels. It must be quiet; that is, the tains. He is not certain. He has not tried higher levels must be arranged in parallel the experiment. He offers the suggestion. strata of something like equal temperature, Perhaps it may be true. so that the rays from the fixed stars may Newton's proposal remained unfertile for pass in smooth curves through the atmos- more than a century. In the mean time telphere to the eye, and not in broken, jagged escopes were being improved beyond his lines such as are indicated by intermittent most sanguine hopes. In the year 1852 Mr. twinkling. If one looks at a twinkling star William Lassell of Liverpool took his powwith a magnifying power of one thousand erful two-foot reflector to Malta in the hope diameters, not only is the star magnified (and with the result) of obtaining better one thousand times, but the twinkling, also, views of the planets. In 1856 Professor is so magnified. High magnifying powers Piazzi-Smyth, Royal Astronomer for Scotcan not be employed except in a most quiet land, made his famous expedition to the
peak of Teneriffe, where he established telescopes at two stations of 8903 and 10,702 feet, respectively. The whole question of good vision was thoroughly studied during a two months stay. The effects of fogs, local clouds, wind, dust, moisture, etc., were noted. The general conclusion was extremely favorable to that particular mountain station. The results of the expedition were printed in scientific journals and also in a popular book which had a wide circulation "Teneriffe, Astronomer's Experiment."
Lassell's expedition of 1852 was, however, the first practical recognition of the fact that a large telescope can only do its work well under conditions especially favorable. These conditions may be found on a high mountain, or (for some work) they may be found at sea-level, as at Malta. If the necessity for a specially favorable site be once recognized, the search for the proper conditions is a matter of detail.
The American Association for the Advancement of Science was the first scientific body to take up the matter. In its meetings of 1868 and 1870 the question was discussed
and a special committee was apFrom a painting by T. Moran
pointed to memorialize Congress on MOUNTAIN CAMP, MT WHITNEY, CALIFORNIA— (12,000)
the importance of an astronomical
observatory at some point on the Pacific a long stay in the Rocky mountains of ColRailroad at as high an altitude as possible orado and reported adversely on the suggeswhere the clearness of the atmosphere and tion to move the twenty-six-inch telescope the great number of cloudless days would to the region examined. The skies were ensure unsurpassed opportunities for astro- clear, but the stars were most unsteady. nomical observation."
No high magnifying powers could be emIt is noteworthy that the clearness of the ployed, and no delicate observations made. atmosphere was the only point spoken of. The eclipse expeditions of July, 1878, to the Nothing was said of the steadiness - by Rocky mountains of Wyoming and Colorado far the most important factor.
familiarized many astronomers with the quesCongress granted an appropriation and tion, and the general verdict on these reexpeditions were sent in 1872 under Mr. gions was that the skies were extraordinCutts and Professor Davidson to points in arily clear, while at the same time the stars the Rocky mountains and in the Sierra were so unsteady as to preclude refined obNevada. Professor Young accompanied the servations. Professor Langley's famous former expedition and his remarkable suc- expedition to Mount Whitney in Southern cess in solar spectroscopic observation at California (1881) showed, on the other hand, his elevated station was soon widely known that this particular station combined both
. In the years 1872-73 the question of a suit- the requisites of a pure and quiet air. able site for the twenty-six inch refractor The plans for Mr. Lick's observatory on of the United States Naval Observatory Mount Hamilton (4209 feet in height) were (then building) was frequently discussed made in 1874, and the observations made among astronomers.
there in 1879, 1881, and 1882, called attenIn the summer of the latter year I made tion to the excellence of the selected site. The observatory on Etna, built in 1881, sixty thousand dollars. Again, such estabbut proposed by Professor Tacchini as early lishments are very expensive to maintain. as 1871, performed the same service for Transportation to the summit of Mont-Blanc Europe. It may fairly be said that the costs about fifty-two cents per pound, many mountain observatories now built or for example. There are difficulties in building in all parts of the world are the arranging for an adequate food and water children of the observatories on Etna and supply (though melted snow is always availMount Hamilton.
able on the higher peaks). In the United In the choice of the Mount Hamilton sta- States (owing to our deplorable policy in the tion the principle was clearly laid down that matter of forest-conservation) bush fires no site should be selected until it had been which fill the air with haze, are very troublepreviously tested, and until the test had
some. On the highest peaks snow-blindness shown a marked improvement over condi- is a constant danger. Mountain-sickness tions at the level of the sea. This is the (giddiness, nausea, great discomfort and essence of the whole matter, It is neces- disorder) is almost always felt. The experisary to test the conditions before establish- ments of Mr. Whymper and others, in the ing the station, because experience has high Andes and elsewhere, show that long shown that only a few out of many avail- residence at high levels may enable one to able mountains are suitable for astronomi- resist acute attacks of mountain-sickness. cal observations.
But no amount of habitude, apparently, There are many objections to mountain can counteract the "diminished living' stations. The cost of building is very large. which results from an insufficient supply of M. Vallot's Observatory on the flanks of air for breathing. Observers at extreme Mont-Blanc (14,321 feet), cost seventy-four altitudes must always be subjected to great dollars per cubic metre. The cost of M. discomfort, and their abilities must be corJanssen's small observatory building on the respondingly decreased. De Saussure, in summit (15,781 feet) is said to have been his expedition to Mont-Blanc, remarks that
From a negative by Joseph Le Conte, Jr., reprinted from the Bulletin of the Sierra Club