Fan. 19, 1871] 
NATURE 
ios) 
ios) 

about forty-five in each group, will be allowed to come to 
London for the six weeks’ course of training. They will receive 
their travelling expenses, namely, second-class railway fare, and 
30s. a week while in London. The results of the teachers’ 
examination will not be published. Each candidate will be 
informed of the position in which he would have been flaced 
had he been examined as an ordinary candidate for honours. 
If he wish his success recorded, it will be done in the ordinary 
way. The Biology course will commence on the 14th June, and 
the course on Experimental Physics on the 5th July. It must be 
understood that no teachers, except such as come up under the 
foregoing rules, will have travelling allowances under § lxviii. 
of the Science Directory. No persons are eligible to receive 
the allowances granted in this minute except those who have 
been engaged in science teaching under the Science and Art 
Department during the session 1870-71. 
It appears from Mr. Glaisher’s Meteorological Tables, that 
while December 25 was the severest day of the recent frost in the 
neighbourhood of London, it was still more intense in other 
localities on January 1, falling as low as 4°9° at Wolver- 
hampton, 5’0° at Hull, 6°7° at Bradford, 7‘0° at Leeds, and 9°7° at 
Leicester, the minimum at Blackheath on that day being as high 
as 19°2°, although at Twickenham, as reported by Mr. Hall last 
week, the thermometer fell as low as 673°. As on Christmas 
Day the severest cold was again in the Midland and North Mid- 
land counties, and we have once more to record the phenomenon 
to which we have had occasion to allude more than once recently, 
that the frost was considerably more intense in England than in 
Scotland. Forthe week ending January 7, no lower temperature 
was recorded at any of the Scotch stations than 21 ‘o°, at Dundee ; 
the mean temperature for all the English stations was 29°6°, while 
for all the Scotch stations it was 355°, or more than 6° higher. 
From the 20th of December to the 13th of January, when the frost 
finally broke up, the temperature in London was only even 
slightly above the mean of the last fifty years on three days. 
Tue Rey. Mr. Gribble, F.R.S., reports from Constantinople 
that after a fine morning the disc of the sun in the late eclipse 
was obscured for some time, so that it was not well seen until 
3 26™ mean time, when there was only about one-eighth of the 
disc clear. A large solar spot then became uncovered ; clouds 
coming on again, this was all that was seen clearly. At 32 26™ 
the light was considerable. 
THE Scottish Naturalist, to which we referred some weeks 
since as a new periodical proposed to be issued under the auspices 
of the Perthshire Society of Natural Science, has made a good 
beginning. Opening with a short programme of future opera- 
tions, in which the editor, Dr. Buchanan White, wisely states 
his intention of restricting the contributions to papers and 
notes especially bearing on Scottish Natural History ; we then 
have an article by Dr. Lauder Lindsay ‘‘On Natural Science 
Chairs in our Universities,” to which we may possibly take oc- 
casion againto refer. The writer deals with a bold hand with 
the evils which are said to prevail more especially in the election 
of Professors in our northern Universities. He refers to the manner 
in which these appointments are stated often to be regulated by 
political influence or religious belief rather than by possession of 
qualifications to teach Natural Science, and is especially severe 
on the system of personal canyass and the ‘‘ testimonial nuisance.” 
Mr. J. A. Harker contributes a paper ‘‘ On the Work and In- 
fluence of Local Natural History Societies ;” Mr. George Nor- 
man a List of the Noctuze occurring in Morayshire ; the editor 
some hints on Sugar'ng, how, when, and where to do it ; and 
an anonymous contributor, a paper “* On the Mollusca of the 
North-east of Scotland,” illustrated with a map. Some shorter 
articles and notes with reports of proceedings of Scottish Natural 
History Societies, make up the number, which we commend to 
the notice of all interested in natural history across the Border. 

HENDERSON'S PATENT PROCESS FOR 
REFINING CAST-IRON 
A® article was furnished a short time ago, and published 
in NATURE (No. 57, p. 94), respecting a new process 
| for the production of steel by the partial decarburisation of 
| cast-iron, invented by the writer. It was then stated that 
a description of a new process for refining cast-iron would 
soon follow. 
This process supplies a more effective and economical 
process than the English finery or the German reverbe- 
ratory furnace processes for refining cast-iron. It is very 
simple, and does not require any fuel, labour, or expensive 
apparatus; and there is no loss of weight of iron, as the 
impurities go off in vapour. The cost of refining is less 
than one-twentieth of that of the English and German 
processes ; and its effect is more thorough than is possible 
by those systems. 
The agents used are fluorine and oxygen combined. 
The fluorine is derived from any fluoride, and the oxy- 
gen from any substance containing or capable of evolving 
oxygen, which is adapted to use in the manufacture of 
wrought-iron and steel. Fluorspar and pure rich iron 
ores are the most available and economical substances 
for producing these agents, and are applied finely 
powdered and mixed, and placed in receptacles, pre- 
ferably, so as to act from the under side upwards upon 
cast-iron in its molten state. 
The most economical mode of application of this pro- 
cess is to treat the cast-iron in the condition in which it 
flows from the blast furnaces, with fluorspar and iron 
ore, applied in the “chills” or pig moulds used at blast 
furnaces, by being spread over the bottom of the moulds. 
The iron, when tapped from the blast furnace, flows 
into the mould thus prepared ; the heat of the iron causes 
fluorine and oxygen to be liberated, and, by reason of the 
affinities of these substances for silicon and phosphorus, 
these impurities are removed in the form of vapour. The 
reactions in the “ chills” are similar to those of the boiling 
puddling process, and last about five minutes. The metal 
during this period is covered with jets of flame and smoke. 
The resulting metal, with respect to silicon and phos- 
phorus, is as pure as wrought-iron. 
It is preferable to use iron ores containing the largest 
amount of oxygen and the least of silica and phosphorus. 
These conditions exist in “ washed iron sands,” and the 
red hematites of Cumberland and Lancashire. When 
using the hematite ores, varieties that are the easiest to 
reduce to powder are preferred; and the ordinary edge 
running apparatus, with cast-iron rollers revolving in a 
pan, is an excellent one for the purpose. 
The fluorspar and fine ore are passed through a sieve 
of not less than four hundred meshes to the square inch, 
and afterwards mixed so thoroughly as to appear to be 
one substance, in the proportion of one part of fluorspar 
to two parts by weight of iron ore, and are spread one- 
fourth to three-eighths of an inch deep over the “chills,” 
then the iron is run upon them so as to form slabs one 
inch thick. 
The former article gave analyses of refined cast-iron 
produced in the reverberatory furnace. It will be seen by 
comparing the analysis of the refined metal of this pro- 
cess with the analysis of that of the reverberatory furnace 
process, that they are analogous, except that the latter 
contains no silicates or graphite. The refined metal of 
the pig-mould process saves the fuel and time taken for 
refining by the reverberatory furnace process, and shortens 
the time of producing steel or wrought-iron by that process 
fully forty minutes. When using the refined metal of 
this process two workmen can take charge of five ordinary 
boiling puddling furnaces making steel, and six furnaces 
making wrought-iron, as the only labour necessary is 
“balling” and removing it from the furnace. Whenhigh 
| carburised steel is made, “balling” is not required, as 
