336 
NATORE 
[ Fan. 27, 1870 
Cuckows’ Eggs 
WILL you kindly allow me space to thank Prof. Newton for 
the trouble he has taken in replying to my inquiries, although 
I must confess I am still unconyinced ? 
My omission of the name of the eminent odlogist in my last 
letter was entirely accidental, for I had no purpose in concealing 
it, but rather the reverse. My quotation was from a letter of 
Mr. Hewitson’s, in the Fve/d of March 17, 1868. 
Mr, Newton mentions the eggs of the Black Cap Warbler and 
the Tree Pipit, as some indication of the existence of a condition 
which I doubted in my sixth question. I have not found the 
eggs of the Black Cap vary more than this, that in some the 
ground colour was of a warmer tone than in others. The eggs 
of the Tree Pipit, I freely admit, do vary greatly, but their varia- 
tions are all confined to different shades of nearly the same 
colour—viz., purple; ranging from purplish red on the one side, 
to bluish purple on the other, but these variations have, never- 
theless, so much similitude that there is no difficulty in at once 
recognising them, 
Mr, Newton says : “If the eggs in question were not cuckows’, 
what birds Jaid them?” My reply is, simply, that they were laid 
by the birds in whose nests they were found, It seems to me far 
more likely that an egg laid by a certain bird should vary slightly 
from the rest of her eggs in the same nest, than that another 
species should lay eggs varying to the extent mentioned by Dr. 
Baldamus—viz., from vinous red to greenish blue, olive green, 
plain brown, &c., or even pure white, or light blue green, men- 
tioned by Degland and Gerbe, as quoted by Mr. Newton. 
Mr, Newton will excuse me for saying that I did not refer to 
the German authors mentioned by him in the footnote to his 
letter, excepting where quoted by Dr. Baldamus, for unfortu- 
nately I do not possess a knowledge of the German language, 
and am therefore unacquainted with their writings. 
The doubts I have expressed, and still feel, have nothing per- 
sonal in them, but only apply to the theory and the evidence on 
which it is supported. It does seem to me singular that these 
extreme variations of colour in the eggs of the cuckoo should only 
have been remarked in Germany. ‘They do not appear to have 
been observed in Britain. Mr. Newton does not say he has 
found them himself, and admitsthat the evidence on which these 
German eggs are pronounced cuckoos’ might have been more 
satisfactory. Mr. Hewitson says ‘‘few eggs differ less,” and 
Mr. Dawson Rowley has remarked, in a letter to the Me/d, “ I 
believe few men have taken with their own hands so many eggs 
of cuculus canorus as myself ;” and yet his experience does not 
confirm the theory, but the contrary. 
I cannot help feeling that we still want more positive informa- 
tion on this point. Were all the varied eggs alleged to be 
cuckoos’ really laid by that bird? I can easily conceive an en- 
thusiastic naturalist, with a favourite theory to maintain, imagine 
when he takes out of the nest of the hedge-sparrow, or tree 
pipit, an egg rather larger than the rest, but marked and 
coloured in a similar manner, that it is that of the cuckoo, I 
hold, however, that nothing less than fositive proof that it was 
deposited by a cuckoo will suffice. I admit this may be difficult 
to obtain, but it is not the less necessary. A dogma like the 
one in question must be based on evidence that is not only un- 
impeachable, but above suspicion, and this I think the advocates 
of the theory have not yet furnished. 
May I ask you to be good enough to allow my orthography 
of the word ‘‘cuckoo” to remain? With all deference to so 
high an authority as Prof. Newton, I prefer and always use the 
common mode of spelling the word to the one adopted by him, 
as better representing the call-note, from which the name is 
derived. W. J. STERLAND 
January 17 
Dr. Livingstone’s Discoveries 
In the conclusion of a letter which has lately appeared in your 
journal on the subject of Dr. Livingstone’s recent letters, Dr. 
Beke gives the opinion that the river and lake chain which forms 
the main part of the great traveller’s latest discoveries, is the 
head stream of the Nile. Though I am unwilling to differ from 
such an authority as Dr, Beke, yet there appear to me to be 
considerable difficulties in the way of his conclusions. 
Will you allow me to show how it seems equally, if not more 
probable, that Dr. Livingstone, whilst he has ascertained the 
sources of the Nile, has also the merit of being the discoverer of 
the head streams of one of the great rivers which flow to the 
Atlantic, perhaps of the Congo, The Chambeze, the head stream 
of the lake chain in question, has its rise somewhere in the 
eastern part of the great plateau or ridge which skirts the whole 
side of Africa, next the Indian Ocean. Dr. Livingstone crossed 
it in lat. 10° 34’ south; from this it flows first westwards to 
Lake Bangweolo, then north to Lake Moero. The position of 
Lake Moero can only be determined as yet by reference to that 
of Lunda, the capital of the kingdom of the Cazembe, twelve 
miles beyond which town the lake is said to begin. Portuguese 
travellers are the only Europeans who are known to have pre- 
viously visited this town, and the two routes from which we can 
assign it a position on the map, are those of Dr, Lacerda in 
1798, and of Major Monteiro in 1831, These two travellers, with 
their escorts, haye passed over almost the same route from Tete on 
the Zambesi to the Cazembe. From the former traveller there 
remain two astronomically fixed positions in the middle of this 
route, and the latter has published a volume which contains the 
distances and directions of his journey, but no astronomical 
positions. The route of Monteiro then, justified by the now 
ascertained position of Tete at the beginning, and by the positions 
formerly determined by Lacerda for its middle course, gives the 
place of the Cazembe town of Lunda, at its termination, in lat. 
8° 40'S., lon. 28° 20’ E. 
the meridian of Lunda. The centre of Moero would then be in 
the latitude of the south end of Tanganyika, and at about 120 
miles to westward of its longitude. Dr. Livingstone has seen 
the river at its outflow from this lake and also at the point where 
it emerged from the “crack in the mountains of Rua,” when, 
according to his own observation, the river turned to vorth-north- 
west to form Ulenge, a third lake or marsh in the country west 
of Tanganyika. 
‘This north-north-westerly direction would carry this river quite 
out of the line of Tanganyika or of the Albert Nyanza; besides, 
both of these lakes appear to be closed*in on the westem side 
by high mountains. 
The levels of the river also appear to present a great obstacle 
to its joining the Nile lakes. 
Leaving the Valley of the Loangwa, Dr. Livingstone tells us 
that he ascended to a great plateau which extends for 350 miles 
square, southward of Tanganyika. This table-land is at an ele- 
vation of from 3,000 to 6,000 feet above the sea. The valley of 
the Chambeze crosses this plateau from east to west, and the 
river descends from it into the great valley of the Lakes Bang- 
weolo and Moero, not far west from the point where it was 
crossed by Dr. Livingstone. The valley of the Chambeze is no 
doubt one of the greatest hollows in this plateau, and so the 
bed of the river here may be taken to be at the lowest general 
height of the plateau given by Dr. Livingstone—that is, 3,000 
feet, or 200 feet above the Tanganyika. From the point at 
which the Chambeze was crossed, its course is for perhaps 200 
miles westward to Lake Bangweolo, and in this part of its flow 
from the plateau to the valley the fall of the river must be con- 
siderable. Between Bangweolo and Moero the course of per- 
haps 120 miles to northward seems to be through a more level 
part of the valley. Still, here there must be another descent to 
Lake Moero, According to the Portuguese traveller, Monteiro, 
the kingdom of the Cazembe extends on the east and north-east to 
the land of the Auembas, apparently the same as the Luwemba 
of Burton and Speke on the south-east of Tanganyika. His 
country is described as low and flat, and this would seem to be 
confirmed by the absence of current in the marshy rivers visited 
by the Portuguese to the east of Cazembe’s town, and also by the 
Lake Liemba of Dr. Livingstone, which he has found to be the 
termination of a long river-like arm of Tanganyika, stretching 
south-south-east to the north edge of the before-mentioned pla- 
teau. Lake Moero, then, cannot be above the level of Tangan- 
yika, else its outflow would surely be over this level country, 
and not through the mountains to northward. From Lake 
Moero the river flows on through a ‘rent in the Mountains of 
Rua.” In passing through this gorge, it appears certain that 
the river must have a further and rapid descent, lowering its bed 
still more beneath the level of Tanganyika. 
In his letter of 30th May, 1869, from Ujiji, which has the 
brevity of a telegram, Dr. Livingstone says: ‘‘ Tanganyika, Nyige 
Chowambe (Baker’s) are one water, and the head of it is 300 
miles to south of this, The western and central lines of drainage 
