1g2 
NATURE 
perature, near the melting point of the alloy, so that it 
is “burnt,” a number of blowholes, looking like bubbles 
of gas, make their appearance (see Fig. 4, which repre- 
sents commercial brass, containing 30 per cent. of zinc, 
after it has been annealed at 820°). As the temperature 
rises, these blowholes increase in number, and at the 
same time fissures develop round the crystals and 
eventually form a complete network. It appears that an 
alloy, not easily fusible, forms round the crystals, and, 
becoming liquefied, rounds off and corrodes them, thus 
giving the appearance of fissures. These effects are 
more readily produced if traces of lead and tin are pre- 
sent, as is usually the case in commercial brass, and the 
network round the crystals doubtless contains these 
metals. Under these circumstances the test pieces are 
of little tensile strength, and are not malleable. 
M. Charpy prepares the alloys for examination with 
the microscope by etching the polished surface by 
electrolytic attack He points out that the fracture is 
useless as a guide to the mechanical properties of any 
metal or alloy. It has usually been supposed, owing to 
the appearance of the fracture, that a highly crystalline 
metal is necessarily fragile ; but this is far from being 
the case. Brass may be mainly composed of crystals as 
much as-one millimetre in diameter without any inter- 
stitial matter, and yet may have an elongation of 60 
Fic. 4.—Commercial brass, containing traces of lead and tin, 
““burnt”’ by being annealed at 820°. 
per cent. The only deduction that can be drawn from 
the appearance of the fracture is that if the crystalline 
structure is revealed in this way, the metal is brittle and 
of little tensile strength. 
The microscopic structure revealed by etching polished 
surfaces enables the alloys of copper and zinc to be 
divided into three classes—those containing less than 
35 per cent. of zinc, those containing from 35 to 45 per 
cent. of zinc, and those containing more than 45 per cent. 
of zinc. It enables the observer to determine whether 
the metal has been cast, and, according tothe size of the 
grain, whether the casting has been made at a high or a 
low temperature, and what is the nature of the mould. 
It shows the effects of hardening, of annealing at various 
temperatures, and, lastly, shows whether or not the metal 
has been burnt. 
M. Charpy infers, from the identical appearance of 
the alloys containing less than 35 per cent. of zinc, 
that these all consist of isomorphous mixtures of copper 
with the compound Cu,Zn, which contains about 66 per 
cent. of copper. He also confirms the existence of the 
compound CuZn, containing 67°2 per cent. of zinc, which 
forms a perfectly homogeneous alloy under all conditions, 
and finds that if more zinc than this is present, it remains 
in the free state soluble in potash. On the other hand, 
M. Charpy expresses no opinion as to the form in which 
the metals are present in the alloys containing more than 
34 and less than 67 per cent. of zinc. T. K. ROsE. 
NO. 1415, VOL. 55] 
DECEMBER 10, 1896 
Dk. BENJAMIN APTHORP GOULD. 
pe OTHER busy life, devoted to the advancement of 
astronomy, is ended by the death of Dr. B. A. 
Gould. Practically, half a century has passed since his 
name came prominently before the public, in connection 
with the establishment of an astronomical journal in 
America, and throughout this period he has maintained 
a foremost place in the ranks of American astronomers by 
the unwearying energy he has exhibited, and the mass of 
work he has accomplished. For many years he was 
attached to the United States Coast Survey, where, under 
Superintendents Bache and Peirce, he did good service 
in the determination of longitudes at stations along the 
Atlantic seaboard, from New Orleans to the extreme 
north-eastern boundary of the United States. In those 
early days the employment of the method of telegraphic 
signals had not long been in use in America, and was 
scarcely known in Europe, and its subsequent develop- 
ment for longitude investigations owes much to the 
energy that Dr. Gould brought to bear upon problems of 
this character. When the Atlantic cable was successfully 
laid, he perceived the advantages it offered to connect 
the American with the European longitudes, and thus to 
practically reduce the two independent series of deter- 
minations into one complete system. 
It was while engaged on the staff of the Coast Survey, 
and anxious in every way to promote its interests, that he 
became unfortunately embroiled with the Trustees of the 
Dudley Observatory. It is not necessary to make any 
further allusion to this unhappy affair, beyond expressing 
our belief that Dr. Gould was a much-injured and much- 
persecuted man. Conducting, as he was at the time, an 
American journal of high repute, and fully employed on 
the affairs of the Coast Survey, he probably was ill- 
advised to attempt to direct the Dudley Observatory, by 
giving to the institution the leisure that his other occupa- 
tions permitted. But if he erred in judgment he suffered 
severely. That there is abundant evidence to show ; but 
that his reputation rose above the attacks of his perse- 
cutors, is a matter for congratulation. The Dudley fiasco 
came about in 1859, and in the next year Abraham 
Lineoln was elected to the Presidency, the war of 
Secession was imminent, and with the troubles that 
supervened, the Astronomical Journal was suspended. 
Not that Dr. Gould’s industry was less. A glance at the 
Royal Society’s catalogue of papers shows a long list 
attached to his name, and some of them, such as the 
reduction of D’Agelet’s observation, involved consider- 
able labour. It is possible here, however, only to refer 
to his best-known work, the successful establishment of 
an observatory at Cordova, and the great amount of 
work therein accomplished. The observatory itself is the 
outcome of a private expedition that Dr. Gould planned 
to the Argentine Republic, in order to extend to the 
southern hemisphere the system of zone observations that 
Bessel and Argelander had applied to the north. This 
private expedition was welcomed and adopted by the 
Argentine nation, and led to the foundation of that 
national observatory under whose auspices those valu- 
able and extensive catalogues have been published, and 
whose preparation kept Dr. Gould at Cordova some 
fourteen years. While waiting for the full instrumental 
equipment of the observatory, Dr. Gould and his assist- 
ants occupied themselves with the preparation of charts 
of the southern hemisphere, giving the position of those 
stars that could be seen with the naked eye, and assign- 
ing to them magnitudes, which practically extended 
Argelander’s scale to the whole heavens. For this work 
he was awarded the Gold Medal of the Royal Astro- 
nomical Society ; he had been elected a foreign associate 
in 1855. 
Dr. Gould on leaving South America returned to 
Boston. Here, in 1886, after an interruption of twenty- 
