944 
of the American Institute of Electrical Engi- 
neers on Standardization. The inclusion of 
this matter is certainly to be commended, and 
it increases the value of an already valuable 
technical treatise. 
The chapters on electric arcs and are lamps 
will be found to embody the later knowledge and 
developments, such as have only appeared in 
separate scientific papers or technical publi- 
cations. Likewise the section on incandescent 
lamps is fully modern, as could not fail to be 
the case, as it has been revised by Mr. John W. 
Howell, whose authority on the subject is be- 
yond dispute. 
The work has so much calling for commenda- 
tion that it would be surprising if a few slips 
of the pen did not occur. In dealing with such 
a large amount of technical matter it is difficult 
to avoid occasional use of phrases a little crude, 
but if the meaning is clear no harm is done. 
Exception may be taken to some things stated 
as facts, which are still undetermined. For 
example, on page 322, ‘the retention of the 
heat by the bulb’ in inclosed ares is involved 
to save this type of are from inefficiency as com- 
pared with the open air are. Also, just follow- 
ing, it is stated that ‘‘ Evidently a large bulb 
will be less efficient than a small one and 
will also tend to produce a carbon deposit by 
chilling the vapor on its cooler surface.’’? This in- 
volves the inadmissible idea that carbon vapor 
can exist away from the arc flame as such, when 
in fact carbon would be condensed as soot un- 
less burned before leaving the are flame. If we 
deprive the inclosed are too completely of air a 
small bulb is more rapidly rendered opaque by 
soot deposits than a large one. 
There is a manifest inconsistency seen in 
comparing paragraph headed ‘Current and 
Voltage,’ page 312, with paragraph ‘ Efficiency,’ 
page 325. Here the inclosed are is made to 
appear by tests accredited to Freedman, at 
least as efficient as the open air arc, in contra- 
diction to the opening sentence under ‘ Effi-- 
ciency,’ page 322. The fact is that there are 
other measurements of arcs extant which are 
far less favorable to the inclosed are than those 
used in the book, and the former are probably 
nearer the truth. 
The author has, in several instances, wisely 
SCIENCE. 
[N. S. Von. XIII. No. 337. 
availed himself of publications issued by the 
manufacturing companies, and many chapters 
are followed by references to papers and publi- 
cations which have been consulted, though the 
chapters dealing with ares and are lamps are an 
exception. This brings to notice what may 
appear to some as a defect of the work. It is 
evidently not intended to be historical, yet 
names and sometimes dates are used, but there 
appears throughout no consistent policy in that 
respect. Names occur sometimes in connection 
with relatively unimportant suggestions, though 
in other more important connections they are 
omitted. Credit is even given, sometimes, to 
the same worker for certain things and with- 
held at other times, though the objects in the 
latter case may be of the greater practical value. 
Few instances appear to exist in which the 
credit given is misplaced, as with the trans- 
former figured on page 174. Notwithstanding 
this, the work gives ample evidence of the 
ability and industry of its author, and must be 
welcomed as a valuable addition to electrical 
literature. It is well printed, admirably illus- 
trated, and the figures are clear and well chosen. 
ELInu THOMSON. 
Chemical Technology. Edited by BE. CHARLES 
Groves and WiLuiAmM THorpP. Vol. III. 
Gas Lighting, by CHARLES Hunt. Published 
by P. Blakiston’s Son & Co., Philadelphia. 
Large 8vo. Pp. 312. Price $3.50. 
This work deals very fully and satisfactorily 
with the manufacture of gas for the purposes of 
illumination, the various forms of retorts, set- 
tings, condensers, scrubbers, governors, etc., 
being carefully and minutely considered. The 
methods of chemically testing and measuring’ 
the gas are clearly and concisely explained. 
More than one-eighth of the book is devoted 
to oil and water gas, nearly every important 
process for their manufacture being detailed. 
The treatise closes with an excellent chapter on 
burners, all the principal ones being described ; 
no mention is made of the ‘bee Feron,’ a 
French mantle burner of high power using a 
mixture of gas and air under pressure. 
In view of the extended use of inclined re- 
torts, the reviewer considers the treatment of 
this subject too brief; this remark applies also 
