80 SCIENCE. 
When the rivet is put in, it flows out and fills the 
space thus formed, becoming, therefore, of greater 
diameter at the middle than at the ends. When the 
plates are under tension, the rivet will cant, and 
the ring-like projection around its centre will pry the 
plates slightly apart, as Mr. Robinson has satisfac- 
torily demonstrated by experiment, thus allowing the 
escape of the steam in the case of a boiler, and avoid- 
ing an explosion; while, on the removal of the stress, 
the plates come tightly together again, provided the 
strain on the rivet were adapted not to exceed its 
elastic limit. The simple conical reaming-out of the 
holes, however, was not found. to be just what was 
wanted; as it was possible for the metal of the rivet 
to be forced out between the plates farther than was 
wished, preventing their coming together tightly at q 
all, even at first. To obviate this objection was the 
object of Mr. Robinson’s second invention, which — 
consists in cutting out a small hemispherical ring in 
each plate around the rivet-hole, and reaming out to 
this ring, so that when the plates are put together the 
conical enlargement of the hole at the centre is fol- 
lowed by a chamber in the shape of a circular ring; 
and into this ‘ relief-chamber’ the metal of the rivet 
can flow out. But, as the amount of metal to be so 
forced out is never to be great enough to fill this 
chamber, the plates are brought closely together in - 
the process of riveting, while the action of the rivet 
under great pressures is the same as has been de- 
scribed. i 
INTELLIGENCE FROM AMERICAN SCIENTIFIC STATIONS. 
GOVERNMENT ORGANIZATIONS. 
Geological survey. 
Geology. — Prof. L. C. Johnson reports that the 
Ripley group of the cretaceous in Alabama and Mis- 
sissippi presents some curious and interesting fea- 
tures. It is an interrupted formation. Beginning in 
Mississippi, north-west of the Corinth group, it runs 
southward one hundred miles, and there runs out. 
It also appears in the extreme south-east, on the 
Chattahoochee River, in Barbour county, Ala., and 
extends westward to a point undetermined, but not 
reaching the Alabama River. It also occurs as a wedge 
between the elder cretaceous and the great lignitic A. 
Chemistry. —'The chemical division of the survey 
is at work on analyses of alkaline and saline waters 
from the Great Basin, collected by Mr. G. K. Gil- 
bert and I. C. Russell; notably, the waters of Hum- 
boldt River, Walker Lake, Pyramid Lake, Mono Lake, 
Lake Tahoe, ete. There are also on hand, awaiting 
analysis, specimens of water from Helena hot-springs, 
Montana, from warm springs of Emigrant Gulch and 
from Livingston, in the Yellowstone valley, in Mon- 
tana, collected by Dr. A. C. Peale during the past 
summer. 
Prof. F. W. Clarke is also engaged upon a complete 
revision of his specific-gravity tables, which form 
part i. of the Smithsonian Constants of nature. 
A white porcelain-like clay from the Detroit copper- 
mine, near Mono Lake, California, proves, upon analy- 
sis by Professor Clarke, to be a very pure halloysite, 
thus adding another to the list of localities for this 
mineral. 
A mineral sent in from Big Springs, Texas, said to 
occur there in abundance, proves to be a mixture of 
gypsum and sulphur, the latter predominating. 
Miscellaneous. — The topographical parties have all 
returned to the office in Washington. The total area 
surveyed during the season ainounts to fifty-one thou- 
sand square miles. . 
Early in September, while attempting the ascent of 
the ‘ Three Sisters,’ a group of peaks in the Cascade 
range in Oregon, Ensign Hayden, who accompanied 
Mr. J. S. Diller in his reconnaissance of the Cascade 
range, was thrown from the edge of a cliff by the 
crumbling of the rocks, and seriously injured. Asa 
result of the accident, he has recently had to suffer 
an amputation of one of hislegs. The operation was 
performed at Portland, Or. Mr. Diller, in rescuing 
Mr. Hayden, was also hurt, but not seriously, by the 
falling rocks. 
The library of the survey has just secured a copy 
of the. ‘Codex Cortesianus,’ by Léon de Rosny, of 
which eighty copies have just been published in Paris 
(1883). The line of Mexican manuscripts for the study 
of the Maya alphabet, in the library of the survey, is 
now complete, with the exception of a manuscript 
in the possession of Sefior D. Alfredo Chavero, in 
the city of Mexico. It is entitled ‘A MS. explana- 
tion in Italian of the Codex Borgiana, by Fabregat.’ 
Steps are being taken to secure a copy of it for publi- 
cation. 
The manuscript for two survey bulletins has been 
sent to the government printer: viz., No. 3, ‘On the 
fossil faunas of the upper Devonian, along the me- 
ridian of 76° 30’, from Tompkins county, N.Y., to 
Bradford county, Penn.,’ by H. S. Williams; and 
No. 4, ‘ Lists of elevations,’ by Henry Gannett. 
Five volumes of the monographic publications of 
the Hayden survey are still unpublished. The gen- 
eral direction of the completion and publication of 
these quarto reports has been put in charge of the 
director of the geological survey. Two of these vol- 
umes are almost wholly in type, and will be issued 
shortly. 
The London Graphic of Nov. 17 has a double-page 
illustration of the Transept in the Kaibab Grand 
Cafion of Colorado River, which is an engraving re-. 
duced from plate xviii. of the atlas accompanying 
Capt. Dutton’s ‘ Tertiary history of the Grand Cafion’ 
(vol. ii. of the monographs of the survey). 
PUBLIC AND PRIVATE INSTITUTIONS. ~ 
Massachusetts institute of technology. 
The new photographic laboratory. — Since the re- 
‘cent invention of the gelatine dry-plate, photogra- — 
a 
4 
