‘ 
we, ae OF me 
584 
by south, the Eastern Bay affords good shelter to vessels of all 
classes in, from 4 to 12 fathoms, and upon pretty good holding 
ground,” 
The last edition of the ‘‘ Admiralty Channel Pilot” says :— 
“* Off the pitch of the Ness, near the lighthouse, it is steep-to, 
there being 4 fathoms at 100 yards, and 15 fathoms at 330 yards 
from the beach. . . . The roads on either side of Dungen2ss 
afford excellent and extensive anchorage, according to the state 
of the wind, with good holding ground, consisting of fine ‘sand 
over clay and mud.” 
The Chesil bank, to the West of Portland, ina deep embay- 
ment, away from the current of tide, is a remarkable example 
of the heaping-up power of the wind-waves from the south-west, 
as itis piled up at the leeward or eastern end, next Portland, 30 
feet above high water, or treble the normal height above the sea 
of such formations. 
The Harbour Commission of 1840 reported against Dungeness 
as a site for a refuge harbour of artificial formation, on account 
of the continued increase of the spit, as indicated by the necessity 
for altering the position of the lighthouse, which at its re-erection 
in 1792 was 100 yards from the sea, and at the period of a then 
recent survey was 218 yards distant, showing an increase of 118 
yards in 47 years. The orizinal lighthouse was, at the erection 
of its successor in 1792, 640 yards from the shore. The Har- 
bours of Refuge Commission of 1844 also reported on it, referring 
to its excellent anchorage, and the danger of interfering with 
nature in such a spot. The changes in this remarkable forma- 
tion have been so extraordinary, as fully to endorse these official 
conclusions, and the various vicissitudes it has undergone de- 
mand more careful consideration than is usually afforded by 
those who advocate artificial works, the effect of which on these 
nicely-balanced movements would possibly be as problematical 
as the turning of these shingle “fulls” into quarries for building 
purposes would be suicidal, and either course might result in a 
baneful interference with one of the finest natural breakwaters 
on our coasts. J. B. REDMAN 
Dispersaljof Bivalves 
REFERRING to the fact mentioned in Mr. Darwin’s letter, that 
mussels are sonetimes brought up on the point of a hook, it is 
common, in shell collections, to find ‘‘ Heart Cockles” (Zsocardia 
cor), which look exactly as if they had been drilled each with a 
small hole, centred at some point in the opposed edges of the 
two valves. 
These specimens have been taken by the long-line fishermen 
on the Irish coast, and the apparent puncture is caused by the 
animal having closed upon the shank of an accidentally intrusive 
fish-hook with such force as to crush the edges of the shell 
against the steel wire. 
Numbers of this comparatively rare species have been thu; 
procured, for Isocardia will allow itself to be drawn in with the 
line rather than open its doors to new possibilities of danger 
while the hook is within. D, PIDGEON 
Holmwood, Putney Hill, April 12 
The Yellow River and the Fei-ho 
As bearing on the subject of my paper on the hydrology of 
the Chinese rivers, which was published in NATURE (vol. xxii. 
p- 486), I take it upon myself to forward the substance of some 
observations made by Mr. T. W. Kingsmill—president of the 
North-China branch of the Royal Asiatic Society—at a meeting 
of the Society in September, 1880. 
Having made measurements of the cross-section of the Yellow 
River, and having obtained the most reliable information he 
could gather regarding the depth of water and the speed of the 
current at different seasons, Mr. Kingsmill roughly estimates the 
discharge as follows :— 
Extreme low water 18,000 cubic feet per second. 
Ordinary 55 36,030 oe 49 
Flood discharge ... . 112,000 30 » 
The average discharge he is inclined to estimate at about three- 
fourths of the single estimation supplied in Sir George Staunton’s 
narrative ; and he places it at, or rather surmises that future 
careful observations will estimate it to be, 300,000,090 cubic feet 
per hour, or about 83,000 cubic feet per second, 
With reference to the Pei ho, Mr. Kingsmill, from an obser- 
vation made in the summer of 1879, estimated its water-discharge 
at 9000 cubic feet per second. My own estimate was confined 
NATURE 
” [April 20, 1882 
to the winter months; but for reasons given in my paper I con- 
sidered it fairly typical of the whole year, viz. 7700 cubic feet 
per second, That I was justified in so doinz, this independent 
observation of Mr. Kingsmill sufficiently proves. 
H.M.S. Zark, Auckland, February 28 H. B. Guppy 
Table of the Appearance of Rare Lepidoptera in this 
Country in Connection with the Sun-Spots 
THE following table is a numerical abstract of the records re- 
lating to the capture of certain rare lepidopterous species in the 
United Kingdom, condensed from a larger table presenting an 
abstract of the pages of the Magazine of Natural History, Zoo- 
logist, Entomological Magazine, Entomologist, The Entomologist’s 
Weekly Intelligencer, Naturalist, The Entomologist’s Annual, 
The Yorkshire Naturalist, Newmans British Butterflies, and 
other works. It will show the relation existing between the sun- 
spot cycles and the appearance of the species, yet not quite so 
di-tinctly as my larger compilation, since, in order to adapt it to 
the pages of NATURE, it has been necessary to equalise the sun- 
spot cycles, which has caused, I fear, a certain overlapping of 
the cycles of capture, which really are well defined. I was not 
aware until quite recently that any one had been before me in 
this branch or entomolozy, but I now find my remarks in the 
Fournal of Science for August, 1881, corroborated in a previous 
publication (Dr. F. G. Hahn, ‘‘ Ueber die Beziehungen der 
Sonneofleckenperiode zu meteorologischen Erscheinungen,” pp. 
155-157, Leipzig, 1877). This pamphlet is noticed (E. D. 
Archibald, NATURE, vol. xix. p. 145, article, ‘‘ Locusts and 
Sun-S pots”). 
FE Eiht 
roe - | ae 2 . 
|e Sle Je S/Es\E|ealad 22/9 sa 
Years. [Eo/SS/8E/85/S'5)S S/S 63/8.6/5% 
Bele B12 S| 25/22 ]9 OS mo) bos | SS re, 
AEB zE RS PASI Ba S am a 
| oA AAS fa} | \sa q) 
as | | | | 
— —— — —_|— — |} — |—_—_ — — 
1832, 43, 54, 65 I I 4 | 25 2 |309 62) 16) 13) — 433) 
1833, 44. 55, 66] 1] 2 5) |B 2.1382 pa a3} I} — 404 (77 
18 5, 50, 67 | 23 | 14] 11 | 16] 6 |c17 18 10} 5 I | 221 
34, 45. 5! 3 | i 
1835, 46 37 oF 735 | 314) 40) 714) 4 449 r109 138 79 2 |2583/7 
1836, 47, 58, 69 |r2r 7 yes I |r 6 4 14 | 325 
1837, 48, 59, 70 |x62 |233 | 30 | 3] 2] 95| 13,10] 3] 9 | 560 kat 
1838, 49, 69, 71 | 20 3] 20 | xr] I 1345 Gt ic tol pee | 8 | 419) 
1839, 50, 61, 72 | 5 | — 5 Si | 80} 47308} 7| 3) 457 
1840, 51, 62, 73| 9) 3 Vile 2) | 051) ab 20 alae sa — 
1841, 52, 63, 74|—|—|—] 2|--| 9|—|27|5| 4) 8 
1842, 53, 64, 75 |162 | — ae 1] 67 213) 49)|) ==") ia 465 
| | | 
The numbers give the amount of captures in the years speci- 
fied ; but in the case of C. Zdusa and C. Hyalea 10 has been 
placed for every notice of ‘‘abundant,” a 5 for every notice of 
common, the number of captures not being often stated. 
Abbreviations employed + maximum appearance, — minimum 
of appearance, 7 minimum of sun-spots Wolf, M maximum of 
sun-spots Wolf. A. H. SWINTON 
Binfield House, Guildford, March 23 
THE APPLICATION OF ELECTRICITY TO 
SATPS’ LOGS 
HESE are days of rapid scientific progress, and the 
great interest so recently excited by the application 
of electricity, in a new and startling way, to transmit 
information, has been almost eclipsed by the attention 
which its use for lighting and the transmission of power 
has attracted. Though no longer confined to signalling, 
yet this is still its most important use, and one for which 
its employment is being extended in many directions, 
always with the most satisfactory results. It is with the 
| application of electricity this fleet messenger for giving a 
constant record of the rate of a ship, that this article is 
concerned. Before, however, dealing with this matter, it 
will be well to say a few words about logs generally. 
Ordinary ships’ logs are of two kinds, called respectively 
harpoon and taffrail logs. Harpoon logs, which are the 
more extensively used, consist of a cylinder, on one end 
of which works a fan or screw, registering the number of 
revolutions by means of clockwork within the cylinder, 
the dial being visible through a glass face. To the other 
