xii 
CITY AND GUILDS OF LONDON 
INSTITUTE. 
CENTRAL INSTITUTION. 
Summer Courses of Lectures and Laboratory Instruction for TECHNI- 
CAL TEACHERS and others to be held in the Institute’s New Buildings 
in EXHIBITION ROAD. 
I. On the Teaching of GEOMETRY in its TECHNICAL APPLI- 
CATIONS— 
By Prof. O. Henrict, LL.D., F.R.S., commencing on Monday, June 22. 
II. On the TESTING of MATERIALS of CONSTRUCTION, 
with some Applications to the DESIGN of MACHINERY— 
By Prof. W. C. UNWIN, M.1.C.E., commencing on Monday, July 6. 
III. On the Teaching of ELECTRICAL ENGINEERING— 
By Prof. W. E. Ayrton, F.R.S., commencing on Monday, July 20. 
Courses II. and III., consisting of Lectures and Laboratory Instruction, 
will be illustrated by one or more DEMONSTRATIONS in the Inter- 
national INVENTIONS Exhibition. 
Each of the above Courses will extend over two weeks, from ro till 5 daily, 
Saturdays excepted. 
IV. CARRIAGE BUILDING— 
Three Lectures by G. A. THrupp, Esq., on June 29 and 39, and July 2, at 
7 pm. 
V. PLUMBING— 
Four Lectures, with Demonstrations, by W. R. Macurre, Esq., on July 
6, 7, 9, and ro, at 7 p.m. 
Registered TEACHERS of the Institute may, on application to the 
Director, be admitted to any of these Courses without payment of fees. 
_ For further details, and for Syllabuses of the several Courses, apply at 
Gresham College, E.C., or at Exhibition Road, S.W. 
PHILIP MAGNUS, Director and Secretary. 
_ HUDDERSFIELD TECHNICAL 
SCHOOL and MECHANICS’ INSTITUTE. 
The Governors will shortly appoint a Professor of Physical Science and 
Mathematics. Salary £250 per year. Intending Candidates should apply 
to the SECRETARY for a statement of duties and other particulars. 
Applications must be sent in on or before WEDNESDAY, June 17. 
AUSTIN KEEN, Secretary 
Dated May 27, 1885 
SANITARY CONGRESS AND 
EXHIBITION. 
The Sanitary Institute of Great Britain will hold its Eighth Congress at 
Leicester on SEPTEMBER 22 and following days. 
The Council invite Papers on Subjects connected with Sanitary Science. 
Full particulars as to the conditions under which Papers are accepted can 
be obtained on applicaticn to the SECRETARY. 
The Health Exhibition, including Sanitary Apparatus and Appliances, will 
be held at the same time, and details are ready for distribution, 74a, 
Margaret Street, London, W. 
E. WHITE WALLIS, Secretary. 
WANTED an ASSISTANT for EXPERI- 
MENTAL RESEARCH. Must have good knowledge of Chemistry 
and Physics. Address, stating Qualifications and Salary required, 
X, Y, Z, care of Publisher of NATURE, 29, Bedford Street, Strand. 
GEOLOGICAL and other WORKS, Part of 
the LIBRARY of a deceased Professor, to be disposed of by Private 
Treaty.—Address GroLocy, care of Willing’s Advertising . Offices, 
125, Strand, W.C. 
ICROSCOPIC OBJECTS FOR HIRE, 
Histological, Botanical, Geological, by the best Mounters. Let 
out on most moderate terms. Particulars of B. WELLS, Dalmain 
Road, Forest Hill. [302 
PATERSON & COOPER, 
76, LITTLE BRITAIN, LONDON, E.C. 
Electric Light and Power and Telephone Engineers, 
New Electric Light Catalogue, post free rs. 
PATERSON & COOPER beg to give notice that they have disposed of 
the Philosophical, Educational, and Experimental Part of their Business to 
Messrs. J. and T. MAYFIELD, 41, Queen Victoria Street, E.C. 
SIX PRIZE MEDALS 
AWARDED FOR GEOLOGICAL COLLECTIONS. 
Geological Collections especially adapted for Teaching as supplied to Science 
and Art Department, and used by all Lecturers and Teachers in 
Great Britain, &c. 
New and Rare Minerals constantly av:iving from all parts for selection of 
Single Specimens. 
ROCK SECTIONS AND ROCK SPECIMENS: 
The Largest Variety in England. 
New Catalogues and Lists onapplication to— 
-JAMES R. GREGORY, 
88, CHARLOTTE STREET, FITZROY SQUARE, LONDON. 
Established 27 Years in London. 
NATURE 
[ Fune 11, 1885 
LIVING SPECIMENS FOR THE MICROSCOPE. 
GOLD MEDAL awarded at the FISHERIES EXHIBITION to 
THOMAS BOLTON, 57, NEWHALL STREET, BIRMINGHAM. 
who has last week sent to his subscribers Chatogaster Limnzi, with 
drawing and description. He has also sent out Leptodora hyalina, Lo- 
phopus crystallinus, Paludicella Ehrenbergi, Spongilla fluviatilis, Syncoryne 
frutescens, Clava squamata, Cordylophora lacustris, Notommata_brachionus, 
Asplanchna Ebbesbornii, Nais hamata, Hydrodictyon utriculatum ; also 
Hydra, Vorticella, Amoeba, Crayfish, and other Specimens for (Huxley and 
Martin’s) Biological Laboratory work. 
Weekly Announcements will be made in this place of Organisms T. B. is 
supplying. 
Specimen Tube, One Shilling, post free. 
Twenty-six Tubesin course of Six Months for Subscription of £1 iS. 
or Twelve Tubes for 10s. 6d. 
Portfolio of Drawings, Ten Parts, 1s. each. 
NOTICE OF REMOVAL. 
F. G. CUTTELL, 49, Beprorp STREET, STRAND, Preparer of Rocks, 
&c, to H.M. Geological Survey, &c., begs to announce that on and after 
July x next his Address will be 
30, BERNARD STREET, W. 
In consequence of removal, several Rock-Cutting Machines 
disposal, at reduced prices. 
HOW & CO.’S ; 
Geological Transparencies for the Lantern. 
Descriptive Catalogue on Application. 
WALKER’S SPECIFIC GRAVITY BALANCE FOR ROCKS 
AND MINERALS. 
HOW & CO.’S POCKET MICROSCOPE LAMP. 8s. 6d. _ 
MICRO-PETROLOGY.—Sections of Pitchstones, Obsidians, Granites, 
Syenites, Diorites, Gabbros, Dolerites, Basalts, Tachylites, ‘Trachytes, 
\ndesites, Porphyrites, Rhyolites, Lavas, Ashes, Gneiss, Schists, Lime- 
stones, &c., price 1s. 6d. each, 
JAMES HOw & CO., 73, Farrincpon STREET, Lonpon. 
MINERALOGY AND GEOLOGY. 
PROFESSORS, COLLECTORS and VISITORS to LONDON are 
INVITED to INSPECT Mr. HENSON’S STOCK of CHOICE MINE- 
RALS, &c., &c. At the PRESENT TIME he has a PARTICULARLY 
FINE CRYSTALLISED NUGGET of NATIVE GOLD, WEIGHT 9 oz., 
PINK AP.)PHYLLITE, CHESSYLITE, EMERALDS on MATRIX, 
PYROMORPHITE (very RARE FoRM), CERUSSITE, CRYSTALL- 
ISED MALACHITE, and BOTRYOIDAL CHALCEDONY, ME- 
TEORIC IRONS and STONES. POLISHED AGATES and LABRA- 
DORITES. 
A Large Series of ROCKS, also MICROSCOPIC SECTIONS of the 
same. 
Lists on Application. 
PRIVATE LESSONS AND EVENING CLASSES. 
BLOWPIPE CASES AND APPARATUS. Catalogues free. 
SAMUEL HENSON, 
277, STRAND, LONDON. 
Opposite Norfolk Street. 
SCIENCE AND ART DEPARTMENT 
50 PER CENT. GRANT FOR THE PURCHASE OF STANDARD 
COLLECTIONS AND APPARATUS FOR TEACHING GEOLOGY 
AND MINERALOGY. NEW LISTS and FORMS on which the 
Application is to be made supplied by 
THOMAS J. DOWNING, 
Geologist, &c., 
38, WHISKIN STREET, LONDON, E.C. (over Quarter of a Century). 
CALVER has received HIGHEST 
AWARD for ‘‘ Excellence and Improvements” in Reflecting Telescopes 
exhibited at the International Exhibition, London.—Descriptive Cata- 
logues, twelve stamps. 
G. CALVER, F.R.A.S., Widford, Chelmsford. 
are for 
Hammers, Chisels, and Hammer Straps. 
G. 
EDWARD WARD has pleasure in an- 
nouncing the issue of a new Micro-Slide of Zoophyte, with tentacles 
out, in the special manner so well known to his numerous patrons. 
= 
Plumularia similis... «.  (post-free) 2 8 
Also, quite new :-— 
Gorgonia verrucosa (polype stained) ,, 22 
Podalirus typicus (Spectre Shrimp) “Fi I 2 
EDWARD WARD, 249, OXFORD STREET, MANCHESTER. [503 
