124 
differ considerably in different portions of the square. On these 
grounds, it would be a mistake, scientifically, to correct the 
averages of the actual observations on the large chart, in the 
present state of our knowledge. These should be printed with 
none except instrumental corrections ; and as we have already 
said, the mean hour of the day and the mean day of the month 
of each average should be given ; for if this be not done, the re- 
sults of the discussion can be turned to no strict scientific use 
whatever. 
But it is quite otherwise in discussing te data entered on the 
large chart, with the view of arriving at some knowledge of the 
distribut’on of pressur2 over this important part of the ocean. 
As we stated before, ‘‘such a discussion necessarily calls for a 
‘preliminary preparation of the results by the application of such 
approximate corrections for range as we are in possession of,” 
and of these corrections Fitzroy’s, to which Mr. Symons refers, 
are among the most valuable. To have attempted such a dis- 
cussion, disregarding the correction for range, is a grave mis- 
take ; and we can scarcely suppose the Meteorological Commit- 
tee will sanction it when they ultimately decide on the method 
of discussion to be adopted. 
Fitzroy recognised the vital importance of range corrections in 
such discussions ; and with this view the monograph above re- 
ferred to was published under his direction upwards of eleven 
yearsago. It would be well if a series of such monographs 
were prepared under the direction of the Meteorological Co m- 
mittee, as necessary preliminaries, which indeed they are, to the 
discussion of the meteorology of each portion of the ocean they 
underiake to discuss, Your REVIEWER 
Rainfall at Barbados 
I po not know whether the following notice is worthy of ad- 
mission into NATURE, but it suggests many interesting conse- 
quences as the effects of heavy rains over continents drained by 
large rivers. 
A very intelligent naturalist, writing to me from Tobago, 
states :— 
“ During August we had an influx of fresh water all alohg our 
southern coast, and throughout the whole extent the sea eggs 
crawled ashore, and died in great numbers. No one has seen 
the like before. I have no doubt the fresh water was the cause 
of the mortality, and that ocher shells also suffered.” 
I have not the means of ascertaining the rainfall of the basins 
drained by the Orinoco and Amazon, but we in Barbados, and 
most of the islands in these seas, have been suffering for many 
months from a protracted drought. Have there been excessive 
rains on the Continent ? 
Tobago is at least 150 miles from the mouth of the Orinoco, 
and 900 miles from that of the Amazon. It is well known that 
the outflows of both rivers sweep round, and form a swift ocean 
current impinging on, and passing by, Tobago, whither they 
carry drift wood, seeds, and other products of the shore. But 
I never before heard of the quality of the water being affected to 
so great a distance. 
] fear that no person had the curiosity to test the density or 
quality of the water. I shall inquire of my correspondent. 
Barbados, Nov. 11 Rawson W. RAwsoN 
Treatise on Probability 
THERE has been no doubt as to the author or authors of the 
* Treatise on Probability,” published under the superintendence 
of the Society for the Diffusion of Useful Knowledge, since 1844. 
In that year the ‘‘ Value of Annuities and Reversionary Pay- 
ments,” by David Jones, was issued in two volumes by Robert 
Baldwin, of 47, Paternoster Row, and the title-page states— 
‘To which is appended a ‘ Treatise on Probability,’ by Sir John 
William Lubbock, Bart., F.R.S., and J. E. Drinkwater Bethune, 
Esq., A.M.” Sir John Lubbock’s name also appears on the 
opposite page, with his first Christian name properly affixed, and 
this is repeated at the end of the volume in a catalogue of the 
works published by that society. The treatise consists of 64 
octavo pages, and was one of the best on the subject at the time 
it was first issued. The late Prof. De Morgan alludes to it in 
the English Cyclopzedia, and Mr. Todhunter quotes ‘‘ Lubbock 
and Drinkwater” no fewer than ten times in his “ History of 
Probability,” published in 1865. T. T. WILKINSON 
NATURE 
' were numerous rivers of liquid light, that as they flowed 
‘e 
|Dee. 19, 1872 
THE HAWAIIAN VOLCANO, MAUNA LOA d 
qa following condensed account of the visit of a 
party to the summit of the Hawaiian Volcano, 
Mauna Loa, at present in a state of fearful activity, ap- 
pears in the Zzses of November 23, from the pen of 
Prof. F, L, Clarke. 
“From Kaalualu, on the southern side of Hawaii, 
where we left the steamer on the afternoon of the 4th, we | 
procured horses and proceeded to Wiohinu, where we re- 
mained for the night, and started next morning; and, © 
after travelling a distance of twenty-five miles over a very 
rough road, although it is considered one of the best, we © 
reached Lyman’s ranch, where we were kindly received, 
and passed the night. The following morning, at day- — 
light, our friends having exerted themselves in procuring © 
the services of an experienced guide, we resumed our 
journey, and after stopping at several ranches for rest 
and refreshment, during the forenoon of the 6th, we 
emerged from the woods, which opened upon an immense 
field of pa-hoe-hoe. The lava fields in this region exceed _ 
in wildness and confusion the most extravagant imagina- 
tion. For miles around, as far as the eye could reach, 
great masses of once molten lava were tossed into a 
thousand grotesque shapes. After travelling several hours 
over the roughest kind of ground imaginable, we reached 
a rude kind of gateway that was formed by gigantic 
columns of lava rock, through which we passed, and 
reached the edge of a rough pali, from whence we were 
able to look out upon the summit. To our sight rose a 
remarkable pillar, towering high up black against the sky, 
and on every hand yawned deep crevices and spentlava _ 
waves which had dashed together in various stapes and 
cooled. y 
“After reaching a favourable spot, where we left our 
animals secured tor the night, we proceeded about 500 
yards over a narrow strip of rugged lava, when we sud- 
denly found ourselves upon the edge of the crater of 
Moku-weo-weo, on the very summit of Mauna Loa, situ- 
ated about 1,400 feet above the sea level. Before us 
yawned a fearful chasm, with perpendicular black walls 
some 800 feet in depth, carrying the eye to where, in the 
darkness of the lower basin, there sprang up in a glori- 
ously brilliant light a mighty fountain of clear molten 
lava, and looking across and below us, at a distance 
probably of three-quarters of a mile, there arose from a 
cone in the south-west corner of the lower basin a mag- 
nificent column of liquid lava, about seventy-five feet in 
diameter, that sent its volume of molten matter to a 
height of nearly 200 feet in a compact and powerful jet. 
The axis of this gigantic fountain inclined somewhat to- 
ward us, so that the descending cascade fell clear and dis- 
tinct from the upward shooting jet, forming a column of 
continuous liquid metal surpassingly bright and beautiful 
to gaze upon. Flowing down the sides of the symmetrical 
cone, which the falling stream of lava was rapidly forming, 
away, spreading and crossing, formed a lake of rivulets 
constantly widening and interlacing, which presented a 
beautiful and unique appearance. 
“When we reached the summit of the mountain, the 
subdued roar of the pent-up gases was fearfully distinct 
as they rushed through the openings which their force had 
rent in the solid bed of the basin, and when we were in 
full view of the grand display our ears were filled with 
the mighty sound as of a tremendous surf rolling in upon 
a level shore, while now and again a mingled crash would 
remind us of the heavy rush of ponderous waves against 
the rocky cliffs of Hawaii.” 
Since the return of the party to Honolulu later advices _ 
state that the crater is increasing in action, and reflecting — 
at night a light of unusual brilliancy, which reaches many © 
miles off shore. The crater in Kilanea, since the present — 
eruption of Moku-weo-weo, has been very irregular in its 
action, which leads to the supposition that the two alter- 
nate, that when one is active the other is passive. 
