582 
NALOEKE 
[APRIL 21, 1904 
several this 
purpose. 
A small weight is suspended by an iron wire constituting 
a torsion pendulum. Direct current is sent through this 
suspending wire and through a magnetising coil which 
surrounds it. This direct current is reversed in the 
magnetising coil (or in the suspending wire) in rhythm with 
the free oscillations of the pendulum. This causes the out- 
side portions of the suspending wire to be magnetised 
successively along right and left helical lines, and the 
accompanying changes of length along the lines of magnet- 
isation cause the wire to twist slightly to right and to left 
with the reversals of current. After several reversals of 
current the oscillations of the torsion pendulum become 
easily perceptible. W. S. FRANKLIN. 
Physical Laboratory, Lehigh University, South 
Bethlehem, Pa., April 6. 
years used the following arrangement for 
Wawo and Palolo Worms. 
Ix your interesting note on the palolo worm of Samoa 
(Nature, March 31, p. 523) an error has crept in about 
the wawo of Rumphius, which is said to be doubtless the 
same as the Pacific palolo. Thanks to the kindness of 
Prof. Max Weber, the head of the Dutch Siboga Expedition, 
that explored the seas of the Malay Archipelago during the 
years 1899-1900, I had the opportunity of examining a 
cluster of these worms from Banda, where they are called 
oelie by the natives; especially in the months of March and 
April, the second and third nights after full moon they 
are swarming there in great numbers at the surface of the 
sea. 
In the * Rumphius-gedenlkboek,’’ consecrated to the 
memory of the eminent naturalist of Amboyna, who aied 
two hundred years before, which was edited by the Koloniaal 
Museum at Haarlem in 1902, I published a short descrip- 
tion and some figures of this interesting worm. Though, 
like the, Pacific palolo, a member of the family of 
Eunicida, the wawo or oelie belongs to the genus Lysidice, 
and is a rather small worm, measuring akout 65 milli- 
metres in length. Nearly all the specimens were in a state 
of sexual maturity, their bodies crammed with sperm or 
ova, but without showing any epitokal characters; the 
number of males and females appears to be nearly equal. 
In our preserved specimens nearly all the colour has 
vanished, but during lifetime males and females un- 
doubtedly are differently coloured, probably green and red, 
as stated by Mr. van Hasselt, the assistant-resident, 
who collected the worms. R. Horst. 
Museum of Natural History, Leyden. 
[Tue writer of the notice merely followed the original 
author, Mr. Woodworth, in identifying the ‘ wawo’’ with 
the palolo. On referring again to Mr.: Woodworth’s article, 
he finds the mode of expression somewhat. ambiguous, so 
that it might possibly bear another interpretation.—EDp1ToR. | 
The Base of Napier’s Logarithms. 
Ix your issue of March 3 (p. 409) I read :—‘‘ The base of 
Burgi’s logarithms is nearly e, and that of Napier’s nearly 
e—*.”’ In the “* Encyklopadie der Elementaren Algebra und 
Analysis,’’ by Heinrich Weber, Leipzig, 1903, p. 108, I 
read :—* Die Basis der Neperschen Logarithmen stimmt 
also sehr nahe mit der Zahl e iiberein.”’ 
Can your reviewer kindly explain on which side lies the 
truth ? ADOLFO BOsseETtI. 
Turin, Italy. 
Wuat Napier actually 
natural sines with a 
which diminish as the 
logarithm is considered to be 
opposite to which it stands, the base is approximately e—'; 
but we may, if we like, regard the logarithms as logarithms 
of cosecants, and the base is then approximately e. Or 
uin (as in “‘ Encycl. Brit.,’’ xvii., 179) we may take 
Napier’s sines as actual integers, and use log Nap n for the 
logarithm placed opposite ” in the table; then we have 
approximately 
gives in his table is a series of 
sponding series of logarithms 
increase. If a Napierian 
the logarithm of the sine 
corr 
sines 
log Nap n=10’ log, (10'/n). 
NO. 1799, Vol. 69] E r 
Thus opposite 5000000, which is entered as the sine of 
30° to radius 10°, we have a logarithm which, read as an 
integer, is approximately 107 log,2. Inspection of Napier’s 
table gives more information than any brief description can . 
do; as will be seen from what has been said, the definition 
of a Napierian logarithm and of its base depends to some 
extent upon how we translate his phraseology into modern 
notation. G: Boie 
BORINGS INTO A CORAL REEF. 
HE work before us consists of a series of reports 
by different authors in connection with the three 
expeditions tha were sent to Funafuti in 1896, 1897 
and 1898. Their object was to obtain by boring a 
vertical core of at least 100 fathoms from the rock of 
a typical atoll, to settle, if possible, the vexed question 
of its formation. Naturally the different parts 
of the work are of unequal value. Indeed, all must be 
regarded as of quite subsidiary importance to that on 
the core, and are of interest mainly in so far as they 
throw light on its composition. 
Little modern scientific work shows a better record 
of determination and thoroughness than this. The 
first expedition under Prof. Sollas was a failure, but 
the experience gained in its two borings of 105 and 72 
feet made possible the subsequent success of the later 
expeditions, and the reports of its members threw a 
flood of light on the atoll itself, its fauna and flora. 
The most valuable direct result was the production of 
a chart giving a more thorough and detailed survey of 
an atoll than had ever before been attempted. The 
great care exercised by Captain Field and the officers 
of H.M.S. Penguin in this work has-made feasible, 
by a re-survey of the atoll in a few decades, a com- 
parison to show the changes that are at present in 
progress. To it we owe the possibility of the detailed 
geological survey of the atoll by Prof. David and Mr. 
Sweet (Section v.), which will be of material assistance 
for the same purpose. The magnetic survey, too, 
worked out by Captain Creak (Section iii.), by point- 
ing out in the areas of greatest disturbance the prob- 
able positions where magnetic rocks might nearest 
approach the surface, suggested the idea of driving a 
boring down through the bottom of the lagoon, sub- 
sequently brilliantly carried out by Mr. Halligan with 
the aid of the captain and officers of H.M.S. Porpoise 
(Section vii.), Fig. 1. 
The second expedition carried the bore to 698 feet, 
but was unsatisfactory in view of the small amount 
of core obtained. It, however, completed the geo- 
logical survey of the islets. Finally, the third expedi- 
tion drove the same boring beyond 1100 feet, the greater 
part of its core being aimost continuous, and put down 
a second in the lagoon to a depth of 245 feet from the 
surface. Collections were also made from the outer 
slopes to 200 fathoms, and the biology of the atoll 
was studied by Mr. Finckh (Section vi.). 
The latter section is, perhaps, the least satisfactory 
part of the whole report, mainly because the examin- 
ation of the core suggests so many questions to which 
no answer is given. Its most interesting observations 
are those on the rates of growth of various organisms, 
a mass of Halimeda three inches in height and thick- 
ness in six weeks being quite remarkable. Attention 
is directed to the barrenness of the eastern or wind- 
ward reef as compared with the western or leeward 
reef. No explanation beyond that of an ‘‘ epidemic ”’ is 
afforded, though whether any is necessary beyond the 
known effects of sediment on coralline ‘life and the 
undercurrents on exposed reefs, both far more im- 
portant to windward, is doubtful. The section gives 
1 “The Atoll of Funafuti.” Being the Report of the Coral Reef Com- 
mittee of the Royal Society. Pp. xiv+428; illustrated, and with 19 
geological maps. (Published by the Royal Society. ) 
