The Providence news. (Providence [R.I.]) 1891-1906, 1901-12-10
ELECTRICAL NOTES.

Tests have recently been carried out
upon three 22o-volt, 2OO-watt Nernst lamps
in Germany. The lives were severally
recorded as l2i, sss and 9se hours All three
lamps were destroyed because the glover
feeding wire melted close to the inca ndes-
cent body, The voltage was continually
220 volts. The candle power dropped from
LAG candles at the start to 90 after 100
hours. ST after 220 hours, Ga after 800
hours and IS after $50 hours. the watts
consumed per candle being 1.S3, 1891. 2l9
2.sS and 2.S9 respectively.
According 10 the eighth edition OF the
list OF cables just published by the In
ternational Telegraphc bureau OF Bern. the
Gummi Ieitung says. there exist 1880
government-owned cables of combined
length of S9,s5l kilomters. and $40 cables
owned by private companies OF total
length of 3ls,2S6 kilometers. The prin-
cipal company, which dispOses OF % cab
les of total length OF 70, 223 kilometers. is
the Eastern Telegraph company of Lon
don. The longest cable Is the one connectln z
Deolen. near Brest with Cape Cod, Mass.
laid down In lS9S by the Compagne Fran
caise, OF Paris, IL measures 5sls kilomet-
ers.
A recent number OF the Bulletin de la
Coclete lnternation des Electricians
says Insurance Engineering, contains a
paper read before that society by Janet,
I'm which he gives the results OF a num-
heI OF laboratory experiments made TO
determine the insulation resistance of
various types OF gloves worn by electric
workmen when handling live wires. The
experiments were performed with the
gloves first dry, then wet. the testing
voltage being los I'm each case. In the dry
test the gloves were nlled with mercury
and suspended In a bath OF mercury; In
the wet test fine sand. dampened with
aciduated water was substituted for the
mercury. The resistance I'm megohms ran
from zero tn 520oo dry and from zero TO
40 wet. ON test by high tension alter
rating currents three samples broke down
ar very low voltage, while three others
broke down at 100, 300 and n 90 respect
lively. The sentiment expressed I'm the
discussion which followed the reading OF
the paper was. that Insulating gloves cam
not be generally relied upon az an effect
I've protection and that wlremen with
gloves should not touch bare conductors,
but only such parts as are already insu-
lated
The contracts for the conversion OF the
tramways OF London 10 electric traction
are exciting keen interest I'm the electrical
world. They will be among some of the
largest known, since the Wofk Will repre-
sent total expenditure of approximate
| ~ SIS 600 000. The ordinary track and slot
rails. fastenings, tie bars are TO he Of
| English manufacture, but there is no
| such stipulation Ia connection with the
| electrical plant and the cross-overs
| since Il IL thought that the British man
ufacturers cannot supply these special
! lines on equal terms with the German
| or American manufacturers The con-
| dult system has been selected. and N
| Is estimated that the cost viii be from
\ $1,000 90 $4,000 per double mile. Sew
eral difficulties will be encountered IN
laying the Conduits, which will consid
! erahly retard the progress Of coustruc.
| ton owing TO the labyrinth OF pipes n
! few inches below the surface OF IN,
| street. 10 II doubtful whether any othei
| city Ia the world possesses such an in-
| tricate underground network of pipes and
| cables a. does the city OF london. 10 is
| confidently expected. however, that th,
electric tramways will be open FOR tram,
| in January 1SoG.