OctToBER 26, 1899] 
NATURE 
621 
Griqualand (about forty-two miles to the north-west of 
the more famous group in the neighbourhood of Kim- 
berley). In this specimen a rather large and irregularly 
shaped pyrope projects from one end of a fragment of 
blue ground : one small diamond is embedded in this 
pyrope, and five others either indent it or are in close 
contact. Fortunately the discoverer was the managing 
director of the company, Mr. G. Trubenbach, who 
appreciated its importance, and so kept a sharp look- 
out for anything remarkable which might turn up during 
the excavations. Accordingly he preserved specimens of 
certain boulders, sometimes over a foot in diameter, well 
rounded and just like stones from a torrent, which oc- 
casionally occurred in the blue ground at various depths 
down to 300 feet. Several of these contained garnets, 
being varieties of eclogite, but diabase was also obtained.! 
Some of these Mr. Trubenbach brought to London, and 
on the outer surface of one a small diamond was detected. 
The boulder was broken, and others were exposed. A 
fragment (rather less than a third) was sent to Sir W. 
Crookes, who entrusted it for examination to the writer, 
and to him Mr. Trubenbach afterwards sent other 
boulders, besides rock and mineral specimens, with the 
permission of the directors. 
In addition to the boulder of diabase, which has no 
special interest beyond the fact of its occurrence, there 
are six boulders of eclogite (one perfect, the rest having 
been broken), all but one (which may have been four or 
five inches long) measuring a foot across, more or less. 
Three of these consist almost entirely of a garnet 
(pyrope) and an augite (chrome diopside), the former 
varying in size from a large pea downwards, and the 
other mineral corresponding. The pyrope is often sur- 
rounded, especially towards the exterior of the boulder, 
by a “kelyphite rim ” consisting mainly of a brown mica. 
This and a few other minerals were present elsewhere, 
but in very small quantities. The remaining three 
boulders consisted of the same two constituents, with the 
addition of a considerable amount of a variety of bastite 
and a few flakes of brown mica. Of the first group of 
specimens two contain diamonds, the first-named having 
at least nine and another certainly one, perhaps a 
second. All are small, the largest being about ‘15 inch 
in diameter. They are well-formed octahedra, with 
slightly stepped faces, perfectly colourless, with an 
excellent lustre. Evidently they are just as much an 
accidental constituent of the eclogite as a zircon might 
be of a granite or syenite. 
This discovery leads to the following conclusions. As 
the diamond is found in boulders of eclogite, and these are 
truly water-worn, that rock is the birth-place, or at any 
rate one birth-place, of the diamond (for its occurrence in 
a more basic species, such as a peridotite, may be ex- 
pected). Hence the diamond is not produced in the blue 
ground, but is present in it as a derivative from older 
rocks, in the same way as the olivine, the garnets, the 
various pyroxenes, &c. Moreover, the blue ground is a 
true clastic rock, and not a serpentinised peridotite of any 
kind, so that the name Kimberlite, proposed for it by 
Prof. Lewis, must disappear from that group. The rock 
is a volcanic breccia, though a rather peculiar one, for 
scoria has not yet been detected in it. Probably it was 
formed by explosions due to pent-up steam, the vents 
being driven through the upper part of the crystalline 
floor and the overlying sedimentaries. These never 
ejected lava, and were soon choked up with shattered 
material. Through this, in all probability, steam or heated 
water continued to be discharged for a considerable time, 
which accounts for the marked changes effected in the 
exterior of the larger fragments and in the more finely 
pulverised material of the matrix. T. G. BONNEY. 
1 The occurrence of boulders in the blue ground at De Beers Mine was 
EY by Stelzner in 1893 (Sztsungber. u. Abhandl. der Isis, 1893; 
p- 71). 
NO. 1565, VOL. 60] 
NOTES. 
WE are informed that copies in bronze of the medal presented 
to Sir G. G. Stokes at his jubilee can now be obtained from 
Messrs. Macmillan and Bowes, Cambridge, price 15s. each. 
AT the opening meeting of the new session of the Institution 
of Civil Engineers, on November 7, an address will be given 
by the president, Sir Douglas Fox, and the prizes and medals 
awarded by the Council will be presented. 
A GOLD medal is offered by the Cercle industriel agricole et 
commercial, Milan, for the description of a method, or the con: 
struction of apparatus, which will assist in the prevention of 
accidents to artizans engaged in electrical work, 
A CONVERSAZIONE of the Geologists’ Association will be 
held in the library of University College on Friday, November 
3. A number of pictures and objects of geological interest wilt 
be on view during the evening. 
TuE Allahabad Pioneer Mail (October 6) states that Mr. 
Douglas Freshfield has started from Darjeeling, with a party of 
friends and Alpine guides, to explore the glaciers and little- 
known passes of the Kanchenjunga range. The exact course 
to be pursued is probably unknown to the party themselves, 
who must be guided by circumstances ; but any addition to the 
scanty and inaccurate information at present extant on the 
subject of the Himalayan giant will be welcome to geographers. 
Ir is stated that another British exploring expedition to 
Abyssinia has been arranged, and will leave England at once. 
The members are Mr. James J. Harrison, Mr. Powell Cotton, 
Mr. W. Fitzhugh Whitehouse (of Newport, Rhode Island) and 
Mr. A. E. Butter. Mr. Donald Clarke will go as surveyor and 
geographer, and a taxidermist will also accompany the party. 
The objects of the expedition are scientific and sporting, and it 
is expected that the journey will occupy about nine months. 
THE thirty-eighth annual general meeting of the Yorkshire 
Naturalists’ Union is to be held at Harrogate to-day, and an 
address upon the evolution of plants will be given by Mr. 
William West, the retiring president. The Union is a model 
of a well-organised local society, which not only serves to 
develop interest in science, but also assists in the extension of 
natural knowledge. The membership is not in any way com- 
mensurate with the importance of the work carried on, and we 
are glad to see that efforts are to be made during the forthcoming 
winter to bring the claims of the Union for support before the 
naturalists and the public of the County of York. 
THE Sritish Central Africa Gazette, published at Zomba, 
always contains several items of scientific interest, and the latest 
number received, dated August 24, is not deficient in this 
respect. We learn from this source that Mr. J. E. S. Moore 
has been taking soundings at the north end of Lake Nyasa. Off 
Ruarwe a depth of 418 fathoms was found, and off the higher 
parts of Livingstone Range bottom was reached at 210 fathoms. 
—Mr. Poulett Weatherley describes in a letter a difficult journey 
up the Luapula, and through its innumerable rapids. The 
Luela is regarded as the second most important tributary of the 
Luapula, but there is little to choose between the Luombwa, 
the Luela, the Mwyangashe and the Luongo, though the 
Luombwa is the largest and most delightful of the four. 
REUTER’S correspondent with Major Gibbons’ trans-African 
expedition reports from Lialui (Barotsiland), in a despatch 
dated August 5, that much valuable exploring work had been 
done by the members of the expedition, The routes traversed 
by the travellers since last January amount in the aggregate to 
3500 miles, mostly through unknown or unexplored districts. 
