494 
NATURE 
[Océ 20, 1870 
commenting on certain alleged facts quoted in an ethnological 
article in Cussel’'s Popular Educator, from Dr. Theodor Waitz’s 
“Introduction to Anthropology,” translated by Mr. Colling- 
wood. Mr. Field justly remarks that facts of such a character, 
“if substantiated, would introduce Accidental Distortion as a co- 
worker with Natural Selection in the modification of species.” 
But he puts the question—‘‘ Do these stories rest on a good 
foundation?” Personally, Ido not know. All I can say is, 
that Dr. Waitz, whose scientific authority is unimpeachable, 
published them without expressing any doubts of their accuracy. 
They may be found with some alleged facts of analogous charac- 
ter, at pp. 83 to 85 of his first volume, as translated by Mr. 
Collingwood. Speaking of animals, he says :— 
“‘Mutilations also are sometimes transmitted. Williamson* 
saw in Carolina dogs which have been deficient in tails for three 
or four generations, in consequence of one of their ancestors 
having accidentally lost it. A cow, three years old, which had 
lost by suppuration her left horn, produced three calves, which, 
instead of the left horn, presented only a small protuberance on 
the skin. Dogs and horses whose tails or ears are clipped, as 
the draught dogs in Kamtschatka, often transmit these deficiencies 
to their offspring.” (p. 83.) : 
Referring next to man, he considers that there are “‘ cases in 
which deformities have shown themselves hereditary ” (p. 84.) 
He says :— 
«Instances of hereditary blindness and deafness, and of alter- 
nating dumbness, so that every second or third child was deaf, 
are given by Lucas. Harris communicates a case of hereditary 
blindness in one eye, and of a double thumb on the right hand.” 
I omit other instances. He continues again :— 
‘‘Instances are not wanting of mutilations that have been 
transmitted from parents to children ; such, however, occur less 
frequently. According to Blumenbach, the children of an 
officer, whose little finger had been cut across and become 
crooked, possessed an analogous defect. Gosse cites the case 
of an officer wounded in the battle of Eylau, who transmitted 
to his offspring a scar on the forehead. Other instances of 
hereditary deformities are found in Wagner” (p. 85). 
As Waitz, it will be perceived, quotes Blumenbach, it may be 
mentioned that the last-named author has a paragraph headed, 
‘Problem proposed. Can mutilations and other artifices give 
commencement of native varieties of. animals?” After showing 
that some have answered the question in the affirmative and 
others in the negative, he adds, ‘‘I have not at present adopted 
as my own either the affirmative or negative of these opinions.” 
See p. 203 of his Anthropological Treatises, translated by 
Mr. Bendyside. 
New facts, capable of being severely tested, would be of great 
value. 
“cc 
THE WRITER OF THE ETHNOLOGICAL PAPERS 
IN ‘*CASSELL’s PopULAR EDUCATOR” 
The Stability of Turret Ships 
SincE the loss of the Caf/aiz an opinion has rapidly gained 
ground, not only amongst unscientific men, but even amongst 
those who from their education should have acquired some of 
the most simple laws of statics, that that noble ship toppled 
over on account of her being ‘‘ top-heavy ”—that the Captain, 
an armour-plated ship with a low freeboard, was more ‘‘ top- 
heavy” than a broadside ship, with more than twice as much out 
of water! The fact is, that her weights were lower and not 
higher than those of other vessels, and therefore that her fault 
was not ‘‘ top-heaviness.”’ 
In looking at the stability of a vessel we take two points—the 
“*centre of gravity” and the ‘‘ centre of buoyancy ;” the former 
being a certain point at which, if the attraction of gravity im- 
pressed a single force equal in intensity to the sum of all its 
separate actions on the component parts of the body, the ulti- 
mate effect would be the same as it is under the system of 
separate actions which really exists. The latter is the centre of 
gravity of the volume of water displaced by the ship, and may be 
regarded as the pivot on which she would turn on heeling over. 
The vessel being in a vertical position, the centre of gravity is 
immediately over the centre of buoyancy, and she is in a state of 
unstable equilibrium, ze. she is in the same fix as a walking- 
stick standing on end. So far in favour of ‘‘top-heaviness.” 
* More specific reference to the authorities on which Waitz rested may be 
found in the foot-notes to his work. Some of the, volumes he quotes are 
foreign, and not to Le found inthe british Museum Library. 
Suppose now that she heels over to one side, what will the 
effect on our centres be? Immediately she begins to heel over 
the centre of buoyancy travels outwards to the side towards which 
she heels, and the centre of gravity being fixed, there will come 
a point when it will exert a force to overcome the heeling over 
pressure. This travelling outwards of the centre of buoyancy 
depends wholly on the shape of the vessel, and will appear per- 
fectly plain by drawing sketches of a ship lying at different 
angles. ‘The more a vessel heels over, the further outwards does 
the centre of buoyancy travel, and the greater is the resistance 
offered to the heeling over pressure until she approaches a certain 
point, then the centre of buoyancy moves out at an increasingly 
slower rate, and finally reaches the position corresponding to that 
of her maximum statical stability. 
Before this, if by any disturbing cause, such as the alteration 
of the wave slope, the ship were inclined beyond her position of 
maximum stability, the resistance to heeling would become less 
the farther she went, until she reached a position at which her 
moment of stability would be the same as before the disturbing 
force began to act. And in this position she would remain in 
unstable equilibrium if the disturbing forces were removed. 
But if she should pass this position before the disturbing forces, 
and the angular velocity caused by them, cease, the ordinary 
movement of the heeling over force would then be greater than 
the resistance offered by the stability, in any position through 
which she would pass, and she would be turned over. 
Now the difference between a high and a low freeboard ship 
as regards stability under sail is this :—The position of maximum 
stability is reached soon after the immersion of the edge of the 
deck ; and as a high freeboard ship does not immerse her deck 
until she has attained a large inclination, while a ship of low 
freeboard will immerse hers at a very much less angle, it follows 
that, in the latter case, the position of maximum stability and 
then of unstable equilibrium is reached at a comparatively small 
angle of heel, and a ship of this construction is much more likely 
to be capsized than one with a high freeboard. Of course, in 
a low-sided ship, the-centre of gravity may be brought so low 
as always to be on the right side of the centre of buoyancy, but 
this is not practicable in an armour-plated turret ship. 
From what we have here stated it will be seen that the error 
in design that made-the Caféazz so much heavier than was ex- 
pected, and draw six fect instead of eight, was not adding so 
much to her stability but was in reality lessening it, and, 
perhaps, was the cause of her loss ; and that if we are to have 
armour-plated turret ships, they must either be built of low 
freeboard, to be propelled by steam alone, or of high freeboard 
sufficient to give stability for sails. 
The feud between naval architects and the advocates of the 
turret system has been going on for ten years back—the former 
contending that a high side was necessary in a rigged sailing 
ship, and the latter, that if they put their guns in turrets, they 
could have low-sided ships, or, in fact, ships with no sides at all, 
after a certain arnount of inclination. : 
That the loss of the Caféazz has resulted from a preventible 
cause is quite evident, and we have shown what that cause is ; 
it, therefore, only remains that if we are to have sailing turret 
ships, we must have high freeboard for the sake of stability. 
T. Bert Licurroor 
Newcastle-upon-Tyne 
The New Postal Act 
AT page 474 Mr. Reeks complains as to the working of the 
new Postal Act. It seems intended to obliterate the old parcel 
post. He says, ‘* Herbarium specimens are not excluded.” 
Perhaps so ; but they are not included. ‘The provisions of the 
new Act are limited to books, written and printed matter, 
genuine trade samples and patterns, so far as regards the 
two ounces for a halfpenny. All parcels other than books, &c., 
as described above, go at the letter rate of one penny for each 
half-ounce. 
The postal card is the thin end of the wedge that will hereafter 
open tous a regular letter rate of a quarter of an ounce for a half- 
penny. For instance: we may now send ordinary business commu- 
nications up to two ounces, thus embodying the matter of twenty 
postal cards, for the halfpenny, if folded in a paper wrapper. 
An ordinary business communication of half-ounce weight goes 
for the halfpenny, if folded as a letter but ieft unsealed. 
Task, If Government will now take an open letter for a half- 
penny, why not take it closed at the same rate? Common sense 
