SEPTEMBER II, 1902] 
Prof. Pickering suggests the use of the charts of the Bonn 
Durchmusterung for this work—and their recent republication 
renders them accessible to all—but he adds that the star images 
are too small to use at the telescope ; in order to overcome this 
difficulty, photographic enlargements, ona scale 1’=o"I cm., of 
the regions for 3° around sixty-nine of these variables, have been 
prepared, and will be forwarded free of cost to experienced 
observers who are willing to cooperate in this work (Czrcu/ar 
No. 53, H.C.O.). 
To render these observations really valuable, they must be 
made systematically and each object must be observed once a 
month, or better still, once a week, by someone amongst the 
cooperated observers. Then again, the observations must be 
recorded on a uniform system of magnitudes, and for this pur- 
pose it is suggested that the combined observations of the Lick, 
Yerkes, McCormick and Harvard observatories for the past 
twenty-five years should be used. When finally reduced and 
brought together, it is expected that these will embrace all stars, 
down to the sixteenth or seventeeth magnitude, for the whole 
of the sky. To facilitate matters further, the whole of the 
magnitudes on Hagen’s charts are being reduced to the photo- 
metric scale, so that all that will then be necessary will be to 
select a star slightly fainter and one slightly brighter than the 
variable, and record the catalogue numbers, with the date. 
Further improvement may be made in the observations if the 
magnitude intervals, and the minute and second of the observa- 
tion, are also recorded, although the latter are not essential in 
the cases of long-period variables. Prof. Pickering concludes 
with the assurance that ‘‘if such observations, for which no 
apparatus but an ordinary telescope is required, are made 
systematically, results of great value will be obtained.” 
THe Lick PHoroGRApHs.—In Sulletin No. 20 of the 
Lick Observatory, Prof. Pickering announces that, as so many 
legitimate requests have been made for the Lick photographs of 
the moon, comets, nebulz, &c.,-it will be possible in the future 
to purchase lantern slides, copies and prints of these objects on 
application to the director of the Lick Observatory. The 
prices and details of these objects may be obtained by teachers, 
lecturers, &c., on application. 
THe Dark Spor ON Jupirer.—In a letter to the Odser- 
vatory, Herr Leo Brenner refutes the idea that the dark spot 
which Messrs. Phillips and Denning observed in the neighbour- 
hood of the Great Red Spot on June 28, is the same spot that 
he recorded, and named the “‘ pyramid-spot” during the oppo- 
sition of 1901. He states that the movement of the pyramid- 
spot during last year was 48° in 85 days, therefore it is im- 
possible for it to have moved the same distance in eight days 
this year, as it must have done if it is the same spot that was 
recorded as being under 19° on June 28. 
we 
THE IRON AND STEEL INSTITUTE. 
MALT ORLE 
THE autumn meeting of the Iron and Steel Institute was 
held at Diisseldorf on September 3 and following days, and 
was attended by an unusually large number of members. 
Mr. | 
William Whitwell, the president, was in the chair, and he was | 
supported by Sir Lowthian Bell, F.R.S., Sir James Kitson, 
M.P., Mr. Snelus, F.R.S., Sir J. J. Jenkins, M.P., Mr. J. 
Walton, M.P., Mr. E. Parkes, M.P., and numerous other 
prominent members from various parts of the world. Addresses 
of welcome were delivered by Mr. von Holleuffer, the governor 
of the Diisseldorf district, on behalf of the Prussian Govern- 
ment, by the Mayor of Diisseldorf on behalf of the city, and 
by Mr. H. Lueg on behalf of the exhibition authorities and the 
local reception committee. Nine papers were then dealt 
with. 
exhaustive account of the progress in the manufacture of pig 
iron in Germany since the Institute last met in Diisseldorf in 
1880. A similar paper dealing with the progress in the manu- 
facture of steel was read by Mr. R. M. Daelen, and Prof. H. 
Wedding read a paper on iron and steel at the Diisseldorf 
exhibition. Prof. Heyn, of Berlin, then read an elaborate 
paper of great scientific and practical interest on the overheating 
of mild steel. The principal conclusions drawn from the 
author’s researches were as follows :— 
When low-carbon mild steel is annealed at temperatures 
above 1000° C., there is an increase in the degree of brittleness if 
the annealing period is sufficiently long. This increase is more | 
considerable, and manifests itself the sooner, the higher the | 
temperature of annealing. | 
NO. 1715, VOL. 66] 
Mr, W. Briigmann read the first paper, which gave an | 
| Brough. 
Prolonged annealing, say uninterrupted-for fourteen’ days, at 
temperatures between 700° and 890’, produces no increase in 
the brittleness. In such cases where the brittleness of the 
material in its initial state was not yet at the lowest degree 
possible, by this treatment the lowest degree of brittleness 
will be attained. Between r1oo° and goo” there exists a tem- 
perature limit, above which, if annealing is carried on for a 
longer period and at an increasing temperature, the degree of 
brittleness increases. Below this limit, however, this is not the 
case. Overheating does not only occur at most extreme white 
heat, but manifests itself at considerably lower temperatures, 
which must, however, exceed the temperature limit just 
referred to. By suitable annealing, the brittleness of over- 
heated low-carbon mild steel can be eliminated. If annealing 
is carried out at above goo° C., a short period of about 
half-an-hour is sufficient. Longer annealing must be the 
more carefully avoided, the more the temperature limit 
between 1100 and goo” is exceeded, otherwise the signs 
of overheating reappear. Below 800° an annealing 
of even five hours is not sufficient to eliminate the 
brittleness in overheated low-carbon mild steel, but by annealing 
of several days’ duration, at temperatures between 700° and 
850°, this object can be attained. If low-carbon mild steel, 
which has been annealed for a longer period at a high enough 
temperature, so that after undisturbed cooling it would show 
extreme brittleness, is rolled or forged during cooling to bright 
red-heat, it will exhibit no brittleness when cold. The fracture 
of overheated low-carbon mild steel generally shows a coarse 
grain, although this is not necessarily always the case. The 
single crystal grains of which the structure of the iron is built up, 
which can be detected under the microscope by suitable etching, 
are often of considerable dimensions when in the state of over- 
heating. Nevertheless, this is not to be considered as proof 
positive that overheating has taken place, since the method of 
cooling also exercises a great influence on the size of the ferrite 
grains. Rapid cooling from the temperature causing over- 
heating produces fine ferrite grains, without reducing the brittle- 
ness appreciably. Moreover, it is possible, by heating low-carbon 
mild steel for days together at between 700° and 890° C., to 
bring the material into such a condition that it will show 
exceedingly coarse ferrite grains, and yet not exhibit brittleness. 
An interesting discussion followed the reading of this paper. 
Mr. J. E. Stead took exception to some of the conclusions. 
Prof. Tschernoff, of St. Petersburg, described his early re- 
searches on the same subject. Mr. Saniter and Mr. Lange 
supported Mr. Stead. 
The first paper dealt with on September 4 was on the com- 
| pression of steel during solidification in the ingot mould, by 
Mr. A. Harmet, of Saint-Etienne. This paper, which covers 64 
pages, was read in abstract by the secretary, Mr. Bennett H. 
Compression with a static pressure acting on the top 
of the ingot is the principle involved in the Whitworth process. 
In the Harmet process the upper portion of the ingot is left 
exposed, and pressure is applied to the base, causing the steel to 
rise in the conical mould as though being forced through a draw- 
plate. The process has been introduced with great success and 
economy at the Saint-Etienne steelworks. In the discussion, 
favourable opinions of the invention were expressed by Mr. 
Beardmore, Mr. Windsor Richards, Mr. Snelus, Prof. Howe, 
of New York, Mr. Vaughan Hughes, Mr. Saniter and Prof. 
Tschernoff. 
Mr. D. Selby-Bigge next read a paper on the application of 
electric power in the iron and steel industries, and Mr. F. 
Kylberg, of Benrath, near Diisseldorf, read a paper describing 
some developments of the use of electricity in ironworks based 
on American experience and adapted to European requirements. 
An interesting discussion followed in which Sir Lowthian Bell, 
Mr. W. H. Massey and several leading continental electrical 
engineers took part. 
Prof. E. D. Campbell and Mr. M. B. Kennedy, of the 
University of Michigan, communicated a paper on the probable 
existence of a new carbide of iron, Fe,C; and Mr. L. F. Gjers 
and Mr. J. H. Harrison gave a report of the results obtained in 
equalising the temperature of hot blast. The proceedings con- 
cluded with the usual votes of thanks to the local reception com- 
mittee and to its hon. secretary, Mr. E. Schrédter, who had 
planned a most attractive programme of visits and excursions. 
The works visited included the Krupp establishment at Essen, 
the Union, Hoerde and Hoesch steelworks at Dortmund, the 
Pheenix works and the Rheinische Stahlwerke at Ruhrort, the 
