NOVEMBER 23, 1916] 
PROF. PERCIVAL LOWELL. 
B* the death, on November 12, of Percival 
Lowell, who equipped the Observatory at 
Flagstaff, Arizona, and planned its work with 
such conspicuous success, astronomy loses one of 
its most ardent disciples and enthusiastic ob- 
servers. Prof. Lowell was born in Boston on 
March 13, 1855, and took his degree at Harvard 
in 1876. He lived in Japan at intervals from 
1883 to 1893, and in the former year was ap- 
pointed Counsellor and Foreign Secretary to the 
Korean Special Mission to the United States. 
His experiences of Eastern life were described 
in several memorable volumes, namely, ‘“Chosém: 
a Sketch of Korea,” “The Soul of the Far East,” 
“Noto: an Unexplored Corner of Japan,” and 
“Occult Japan.” His other publications include 
“Mars,” published in 1895, “The Solar System,” 
*““Mars and its Canals,” ‘Mars as the Abode of 
Life,” “The Evolution of Worlds,” and several 
fine volumes of “Annals of the Lowell Observa- 
tory.” In 1902 he was appointed non-resident 
professor of astronomy of the Massachusetts 
Institute of Technology, and in 1904 he received 
the Janssen medal of the French Astronomical 
Society for his researches on Mars. He had 
many admirers in this country, and was always 
ready to assist enterprises having the advance- 
ment of knowledge as their object. An illustra- 
tion of this characteristic was the support which 
he gave to the Hill Observatory, Sidmouth; and 
he had the distinction ‘of being the only one out- 
side Great Britain who contributed financially to 
the endowment of this new observatory. 
Prof. Lowell’s energy and confidence were 
infectious; he inspired many amateurs with 
worthy ambitions, and encouraged a wide interest 
in the results of observation. For the last twenty- 
five years he had given undivided attention to 
astronomy, and made a well-recognised reputa- 
tion by his researches on planetary markings and 
by his insistence on the bold deductions that he 
considered his observations warranted. What- 
ever opinion may be held as to the deductions 
and interpretations to which he was led, astro- 
nomical science has benefited by the unflagging 
zeal with which he pursued his investigations, 
the undoubted sincerity which inspired his work, 
and the care he exercised to guard himself against 
self-deception. 
Foremost among these precautions may be 
noted his care in selecting a suitable site for his 
observatory. He planned reconnoitring expedi- 
tions furnished with adequate and identical optical 
equipment to various continental~ and insular 
stations where favourable conditions might be 
anticipated, and worked for some time on the arid 
plains of Mexico before deciding that a somewhat 
inaccessible peak in Arizona, about 7ooo ft. high, 
offered the ideal conditions for which he was in 
search. There he erected a 24-in. refractor, and 
began that series of observations on the surface of 
Mars and of other objects the critical examina- 
tion of which offered great difficulties on account 
of minuteness or lack of definite detail. |The 
NO. 2456, VoL. 98] 
NATURE 
231 
interest awakened by these inquiries has only been 
equalled by the controversies to which they have 
given rise. The study of the surface of Mars in 
particular was rewarded by fhe confirmation of 
Schiaparelli’s discovery of a canal system and 
by the existence of a complicated network of 
watercourses that assumed’ various distinct and 
regularly recurring appearances, depending on the 
seasonal conditions that obtained. Sometimes the 
tracks were duplicated, at others they revealed 
thickened patches, conjectured to resemble the 
fertile spots known to us as oases. A complete 
system of planetary meteorology was worked out, 
the migration of the heat equator was traced with 
great exactness, and the interchange of wind 
between the poles and the equator giving rise to 
cyclonic storms and diurnal effects was discussed 
with unusual fullness of attractive -interpreta- 
tion. 
The ill-defined markings on Mercury and Venus 
were submitted to a scrutiny not less searching 
than those of Mars, and Prof. Lowell not only 
produced substantial evidence that these planets 
rotate once only in the course of their orbital 
motions about the sun, but he also determined 
with some accuracy the position of the axis of 
rotation, and constructed a trustworthy map of 
the topographical features of that hemisphere of 
Venus which is visible to us. The minute discs 
of Uranus and Neptune, as well as of the satellites 
of Jupiter, were alike made subjects of the closest 
study, and much interesting detail was collected. 
These, with other, researches were carried out 
with the 24-in. refractor, but quite recently Prof. 
Lowell added a 4o-in. reflector to his observa- 
tory equipment, and with the larger aperture was 
able to confirm the accuracy of much of _ his 
previous observations. He was one of the most 
successful as well as one of the most indefatigable 
of observers, and we trust that those who have 
been so happily connected with him in the con- 
duct of the Lowell Observatory will be able to 
carry on its activities and add fresh lustre to its 
history. 
LOWELL’s CONTRIBUTIONS TO ASTRO- 
NOMICAL SPECTROSCOPY. 
Tue work at the Lowell Observatory has by no 
PRor. 
‘means been restricted to the planet Mars, as may 
have been popularly supposed. Prof. Lowell pro- 
vided the observatory with an equipment of the 
highest class for spectroscopic investigations of 
the heavenly bodies, and, with the capable co- 
operation of Dr. Slipher, some important con- 
tributions to the advancement of astrophysics have 
been made. Besides taking part in the general 
study of the radial velocities of stars, several new 
and difficult investigations of great interest were 
undertaken. One of the first problems attacked 
—in 1903—was that of the rotation of Venus, and 
although the actual period could not be assigned, 
the evidence was decidedly in favour of a period 
much greater than twenty-four hours. More 
recently the first authentic value of the rotation 
period of Uranus was determined by Lowell and 
