- 
FEBRUARY 29, 1884. ] 
be produced by evaporation, which, although too 
small to be observed, may yet be integrated over the 
surface of the earth into a large sum. 
In looking back over the electrical year, we do not 
find any great discoveries. We notice, however, great 
activity in the process of refining old methods. The 
electrical exhibition at Vienna showed a host of ap- 
plications of electricity to the arts. There was, how- 
ever, no striking new invention like the telephone. 
In all civilized countries, the year has brought forth 
innumerable modifications of telephones and tele- 
phonic apparatus. When it had once been shown 
that even an imperfect sentence could be transmit- 
ted by electricity, the dullest inventor could discover, 
among the débdris of his laboratory, magnets and elec- 
tromagnets which needed buta slight twist here and 
there to be made into telephones. A touch of genius 
was necessary for the first twist; and then the whole 
electrical world had the seed of the invention. It is 
rumored that long-distance telephoning will soon be 
attempted with wires of low resistance. 
Electric lighting continues to attract great atten- 
tion; and more correct calculations are daily made, 
which will soon enable us to judge of the relative 
economy of incandescent lighting compared with gas. 
In an address to the Society of arts in London, the 
lamented Dr. Siemens — whose sudden death last 
December has been such a loss not only to electrical 
science, but to science in general — made an elabo- 
rate calculation of the cost of lighting large areas in 
cities, taking the parish of St. James in London as 
an example and also as a unit. He estimated that 
to light London to twenty-five per cent of its total 
lighting-requirements would require an expenditure 
of capital of fourteen million pounds, without includ- 
ing lamps and fittings; making an average capital 
expenditure of a hundred thousand pounds per dis- 
trict. Siemens estimated the cost of lighting by in- 
candescence as twenty-one shillings and nine and a 
half pence per lamp per year; while to produce the 
same luminous effects in a good Argand burner costs 
twenty-nine shillings per year. This apparently shows 
that incandescent lighting is cheaper than lighting 
by gas, at the present price of gas. 
Electric lighting seems to gain in the estimation of 
the public. Even the argument that if the electric- 
light companies were compelled to put their wires 
under ground the companies could not pay their ex- 
penses, and consequently that the public would lose 
the benefits of the electric light, has a strong influ- 
ence upon many who prefer light to darkness in our 
city streets. The public, however, are only beginning 
to realize the dangers from the present method of 
running electric-light wires. A heavy storm at night 
might cause at any time disastrous conflagrations, 
from the electric-light wires coming in contact with 
other wires and with wood-work. The bulletins pub- 
lished by the Edison electric-light company show the 
great extension of his system. His plants are to be 
found in almost every civilized country; and the com- 
pany are paying great attention to village plants. 
The writer of this article is informed that the cost 
of lighting the great steamboat, The Pilgrim, is not 
SCIENCE. 
261 
far from that of gas, with a far better quality of 
light than gas could give. Lighting by incandescence 
is a great luxury; and, as soon as the public imagina- 
tion has been sufficiently stimulated, it promises to 
become a necessity in many quarters. Other systems 
besides that of Edison are competing for the field 
opened for enterprise. 
The practical applications of the storage of elec- 
tricity, so called, have not been numerous during the 
year. It is maintained that it is more economical to 
use electrical accumulators than to light directly from 
dynamo-electric machines. There is still a whole- 
some fear of having several tons of lead left on one’s 
hands in a disintegrated condition. Further experi- 
ments are necessary on an extended scale, with especial 
reference to a large factor of time, before electrical 
accumulators can be pronounced a practical success. 
JOHN TROWBRIDGE. 
BIOGRAPHIES OF NATURALISTS. 
Heroes of science : botanists, zodlogists, and geologists. 
By Prof. P. Martin Duncan, F.R.S., F.L.S., 
etc. (London society for promoting Christian 
knowledge.) New York, E. & J. B. Young & Co. 
348 p. 12°. 
THE plan of the several volumes designated 
by the common title ‘ Heroes of science’ is 
worthy of much commendation. It is a fre- 
quent and irritating experience of those who 
have become interested in scientific men’s lives 
to find that they have a scant place in biographi- 
cal encyclopaedias, and that even the greatest 
figures in that line of human activity are dis- 
missed with epitaphal brevity of description. 
The proper way to meet this difficulty would 
be by preparing an encyclopaedia containing 
only the names of those who had contributed 
something to the store of science. ‘ Heroes 
of science’ has a far simpler aim. Twenty- 
one names from the great muster-roll of men 
who may be termed naturalists are all that 
appear in this book. The first is that of 
Aristotle; the last, that of Lyell. The aim 
of the author is clearly to show how these 
men have played their parts, and something of 
the way in which they turned the course of sci- 
ence in their time. In this aim it seems to 
the present writer that Professor Duncan has 
attained a very substantial success. Within 
the slender space of two hundred and fifty small 
pages it is, of course, impossible to do any thing 
that can be called justice, to more than a score 
of very notable men, mostly of rich and varied 
lives; yet the reader will get a sense of their 
value to the world from the book, that he will 
not obtain elsewhere. Take, for instance, the 
life of Lamarck : though all too briefly told for 
true proportion, it is the best short account of 
