492 
NATURE 
[JULY 1, 1915 


sa similar platinum wire in an evacuted quartz tube. 
Six such combined thermometers were made and 
annealed at 1tooo° C. In the subsequent comparisons 
of the resistances of the platinum and iron wires at 
various temperatures the resistances were determined 
to the equivalent of 0:005° C. In all cases the resist- 
ance of pure iron was found to increase regularly to 
about 750° C., the temperature coefficient of increase 
reaching a maximum about seven times that of 
-platinum at that point. At 757° C. the critical point 
A2 is reached, and the coefficient decreases. At 
=894° C. the second critical point, A3, is reached, and 
the resistance decreases over a range of 10° C., to 
“increase again at higher temperatures. On cooling 
the A3 change occurs at 880° C., while the A2 change 
“occurs again at 757° C. 
THE June issue of the Journal of the Franklin 
Institute contains a second paper by Sir Robert Had- 
‘field on sound steel for rails and structural pur- 
poses, the first having been published in February. 
The present paper gives some details of the produc- 
‘tion for the Pennsylvania Railway Company of one 
hundred tons of rail ingots made at Sheffield under 
‘his ‘“‘sound steel’? system. The dimensions of the 
‘ingots were 5 ft. 4 in. by 18 in. square. They were 
fed from sandheads, which permitted an average of 
130 lb. of fluid steel to pass into the ingot, which 
-contracted during freezing, thus continuously “ fol- 
lowing up’’ any pipe that tended to be formed. ‘The 
-average capacity of the cavity on the top of the ingots 
was 3719 per cent. of the total capacity of the ingot. 
The author claims that after cutting off 10 per cent. 
from the top of the ingot the remaining 90 per cent. 
is sound, entirely free from blowholes, segregation, cr 
piping. Ingots sectioned through the long axis and 
photographed appear to bear out this contention, at 
any rate so far as soundness is concerned. In the 
rail ingot, as ordinarily cast, a discard of upwards of 
-40 per cent, is sometimes necessary, and even in the 
sound portion segregation is always present to a 
greater or less extent. It is interesting to note that 
the average carbon percentage in the ingots is 0°63— 
-a considerably higher figure than any English rail- 
way company permits. This gives a harder but more 
brittle rail. The wear in practice of rails rolled from 
these ingots will be watched with considerable interest. 
THE Scientific American celebrated its seventieth 
anniversary on June 5, and the number for this date 
contains an interesting retrospect through the inven- 
tions and scientific discoveries of the past seventy 
years. When the journal was first established, we 
had only Davy’s are and electrolysis, Oersted and 
Ampére’s revelations in electrodynamics, Daguerre’s 
photography, Henry and Faraday’s work in induction, 
and Joule’s mechanical equivalent of heat. ‘The tele- 
graph and the reaper had just been born. Much of 
‘the transformation which has marked the last seventy 
years has taken place within the lives of men still 
with us. Prior to the invention of the telephone, our 
contemporary considers that the decade 1840-50 was 
the most fruitful in invention; during this period the 
‘reaper, the vulcanisation of rubber, the sewing- 
machine, and the telegraph were perfected. The 
NO. 2383, VOL. 95] 

decade beginning with 1880 saw an outburst of inven- 
tive activity that dwarfed all similar periods in the 
history of invention. It seemed that the discoveries in 
electricity during the last three or four years of the 
previous decade had been the signal for the pent-up 
genius of the world to be let loose. In the ’eighties the 
generation, transmission, and utilisation of current, 
the dynamo, the transformer, and the motor were all 
made practical propositions on a large and commercial 
scale for the first time. The electric furnace was per- 
fected in the latter part of this period. The Harvey 
process for hardening armour plate was invented in 
1888; smokeless powder, the Westinghouse brake, the 
transparent film which foreshadowed the moving pic- 
ture and the pneumatic tyre are also contributions 
of the same decade. There are a large number of 
photographs of historical inventions and inventors in- 
cluded in this number, and there is also an interesting — 
autobiographical sketch by Mr. Nikola Tesla. 
In view of the great interest at the present time in 
the Conventions and signed Declarations of the First 
and Second Hague Conferences, and particularly be- 
cause of the need of accurate information as to rati- 
fications of and adhesions to the Conventions and 
Declarations relating to war, the Carnegie Endow- 
ment for International Peace has prepared a series of 
pamphlets in order that the public may learn from 
trustworthy sources the status of these international 
agreements and the extent to which the Powers now 
at war are bound by their provisions, We have 
received copies from Washington of seventeen of these 
pamphlets, and find that among the subjects of vital 
importance considered are: the declarations of 1899 
concerning asphyxiating gases and expanding bullets, 
and prohibiting the discharge of projectiles and ex- 
plosives from balloons; and the conventions of 1907 
relative to the laying of automatic submarine contact 
mines and concerning bombardment by naval forces 
in time of war. 
THE Open Court Company, 149 Strand, W.C., has 
ready for publication ‘A Budget of Paradoxes,’’ by 
Augustus de Morgan, revised and edited, with full 
bibliographical notes and index, by Prof. David Eugene 
Smith, professor of mathematics, Teachers College, 
Columbia University, New York. 
Messrs. G. P. Purnam’s Sons announce for early 
publication :—‘‘ The Alligator and its Allies,’’ by Prof. 
A. M. Reese; ‘‘ Plane Trigonometry,’”’ by Prof. A. M. 
Harding and J. S. Turner; and ‘Field Book of 
Western Wild Flowers,” by M. Armstrong and Prof. 
J. J. Thornber. 
THE announcements of the Cambridge University 
Press include :—‘‘Mimicry in Butterflies,’ by Prof. 
R. C. Punnett; ‘‘The North-West and North-East 
Passages, 1576-1611,”’ edited by P. F. Alexander (the 
first volume in the series of ‘‘Cambridge Travel 
Books’); and ‘‘ Stories of Exploration and Discovery,” 
by A. B. Archer. 
Errata.—In Prof. O. W. Richardson’s Royal Insti- 
tution discourse printed in NaTuRE of June 24, p. 468, 
col. 2, line 12, for ‘“‘twice”’ read ‘half’; p. 469, col. 1, 
table, for ‘‘calories per n”’ read ‘‘calories per gram- 
molecule of electrons,” 


