NATURE 
{Jfay 4, 1871 


9. Pentlands Cable length 11 nauts. 
10. Scilly Islands Cable ‘ 0 3 on 27 a 
11. Swedish-Russian Cable F . AEROS. 495 
12. Moen Bornholm Cable. 6 5 ee op 80 ,, 
13. Hong-Kong-Shanghae Cable . 9 © NBFEEEZOO! 55 
14. Shanghae-Possiette Cable 3 é 5 Co" 55 
These two latter cables have recently been completed, 
and the Shanghae-Possiette cable is now in course of 
submergence ; the Hong-Kong-Shanghae cable was suc- 
cessfully laid last month. These lines give a total 
distance of over 3,978 nautical miles of submarine cable 
with Hooper’s indiarubber insulation. The following 
observations as regards the electrical conditions of these 
cables as compared with well-known gutta-percha insu- 
lated cables is remarkable. The electrical tests of 
well-known cables with both the gutta-percha and the 
Hooper core are taken at the temperature of 75° Fahr., 
and in terms of British Association (B.A.) units, the 
standard measure now most generally adopted in England 
for comparison : 
Gutta-percha. 
England and Hanover Cable, laid 1866 . 239 million B. A. units 
Persian Gulf Cable a », 1864. 190 ;, A 
Atlantic Cable a 5 a5 1865 6840) tees 5 
Atlantic Cable c 5 “0 1866 Be ee og * 
Vacentia Bay Cable a A 1866 a Gy ss 
Cuba and Florida Cable . », 1807. 464 ;, es 
Hooper Core, 
Ceylon Cable (Hooper’s Core) ,, 1865 HG) 55 3 
India Cable . : 6 », 1865. 8064 ,, 3 
India Cable. : 5 5) 1866. 8526 5, i. 
Wanish-English Cabl : aa) S08). OL23) iy, _ 
Scotch- Norwegian Cable Ape aesicley 7923» a 
Scilly Islands Cable 6 », 1870. 7819 _ ;, 4 
With such results, it is not to be wondered at that the 
relative speed of two cables of similar length and con- 
struction, the one employing a gutta-percha core and the 
other a Hooper core, should be found’ greatly in favour of 
the latter, in the proportion of 130 to 100; that is to say, 
in any given time the Hooper core, from its superior insu- 
lating properties, will transmit thirty per cent. more words 
than a gutta-percha core, a most important circumstance 
when it is considered that the earnings or dividend upon 
each cable is dependent upon the work it can perform in 
a given period. As regards the apparatus employed for 
transmitting the currents through submarine conductors, 
the “Wheatstone” automatic recording system is the 
most successful. By this apparatus an average speed of 
over thirty words a minute is regularly maintained upon 
the Danish-English cable, a distance of 363 nautical 
miles, exclusive of a further land circuit of over 140 miles, 
yaaking a total distance of about 500 miles. This speed 
must be compared with that of seventeen words per 
minute, the highest result recorded over the same circuit 
by the most improved Morse system. From the 
vesults of the “Wheatstone” apparatus working over 
this circuit since September 1868, it appears that 
to obtain maximum speed, the currents through a 
submarine cable require to be transmitted of equal 
duration, at equal intervals, in alternate directions, and 
the line discharged to earth between each successive 
reversal or current to neutralise the charge, all of which 
conditions are fulfilled in the ‘ Wheatstone” Automatic 
Jacquard arrangement, which can only be compared to a 
loom weaving the currents into the line, the sequence of 
the currents representing the pattern on the cloth. This 
apparatus is now organised as the transmitting and re- 
cording register upon the vast system of submarine cir- 
cuits belonging to the Great Northern Telegraph Com- 
pany, and the extensions from Possiette Bay (Russian- 
Chinese frontier) to Nagasaki, Shanghae, and Hong-Kong. 
The subject of high speed transmission through insulated 
conductors, both by land and sea, is one which demands 


special attention, now that the telegraph is daily encroach- 
ing upon the postal service, a service in which both speed 
and accuracy are more than ever demanded by the public. 
NATH. J. HOLMES 
PFLUGER’S;NERVE2ENDINGS IN GLANDS 
N his “ Archiv ftir die Gesammte Physiologie” (Bonn, 
1871), E. Pfliiger gives a short and summary answer 
to those many observers who have thrown doubt on the 
accuracy of his remarkable discoveries as to the conti- 
nuity of nerves with the secreting cells of the salivary glands 
and liver. Pfliiger’s opponents in this matter have been 
Mayer, Hering, Krause, Henle, and Schweigger-Seidel. The 
objections which have been made are divided by him into 
three heads. 1st. It was said that the nerves he had seen 
were capillary vessels. 2nd. That they were threads of 
mucus. 3rd. They were disintegrated fat. These objec- 
tions are successively shown to be groundless, and 
Pfliiger stoutly maintains his original position. What is 
far more important in this short paper than these answers 
to objections is that the professor at length publishes an 
account of some of his methods as to which he has so 
long left every one in the dark. They are certain to be in- 
teresting to some of our readers. Salivary glands. A 
fresh submaxillary gland from the ox must be taken, and 
very fine sections made ; these must be at once teased 
out in perosmic acid sp. gr. 1003, and covered with a thin 
glass in a shallow cell. A great many preparations should 
be made, and the best picked out. They will be suf- 
ficiently stained in 24 hours. As the water dries up it 
may be replaced by glycerine. Zzver. A great number of 
very fine sections must be made from the fresh liver of a 
dog or pig. These sections must be placed Io or 12 
together in watch-glasses filled with Beale’s carmine solu- 
tion, and thus kept ina moist chamber 14 days. The 
sections must then be taken out, washed one by one ina 
drop of perosmic acid, sp. gr. 1003, transported to a fresh 
drop of the same on a slide, and carefully teased out, 
covered, and examined. 


NOTES 
St. BARTHOLOMEW’s HospPITAL has, we lear from the 
British Medical Fournal, sustained a great loss in the resignation 
by Mr. Paget of his active duties as Surgeon to the Hospital. 
Mr. Paget will, of course, receive the appointment of Ceonsult- 
ing Surgeon to the Institution which he has served long and 
faithfully, and on which he has conferred lustre. 
THE following excursions have been arranged by the Geologists’ 
Association to take place in May :—To Oxford on Friday, 12th 
May. On arriving at Oxford the New University Museum will 
be visited. Subsequently the party, accompanied by the Presi- 
dent, Prof. Phillips, and Prof. Morris, will walk to Shotover 
Hill, where the Middle and Upper Oolites are well exposed. To 
Grays, Essex, on Saturday, 20th May. Exposures of the 
Mammaliferous beds of the Thames Valley, and afterwards 
sections of the Upper Chalk will be visited, under the guidance 
of Prof. Morris. A four days’ excursion to Yeovil, Weymouth, 
and Portland is proposed for Whitsuntide. Particulars of 
arrangements will be duly announced. 
THE Edinburgh Naturalists’ Field Club, which has since its 
formation carried on active operation only from April to July 
inclusive, held its adjourned annual meeting and conversazione 
on Saturday, the 22nd April, when Mr. Robert Scot-Skirving, 
the president, delivered an introductory address, enlarging 
mainly on entomology as a fit summer field study. The business 
meeting was held in November last, when, in addition to the 
