Chapter XIV: TECHNOLOGY.--Employment of Acetic or Formic Acid in (5)

Wheels and Rope for conveying power long distances. Send for circular.

STANDARD

TRADE MARK]

The Original Unvulcanized Packing

CALLED THE STANDARD

--As it is the Packing by which all others are compared. Accept no packing as JENKINS PACKING unless stamped with our "Trade Mark."

=JENKINS BROS. {71 John Street, N. Y.
{105 Milk Street, Boston.
{13 So. Fourth St., Phila.=

GAS ENGINES.

Best in principle, workmanship, and materials. An unequaled small Motor adapted to all uses. When the motor is not at work, the expense of running it ceases. =Simple, Safe, Economical, Durable. No extra insurance.= Four sizes: 1 H. P., ½ H. P., 1 man power, and Dental Engine. These Engines are especially suited for Gasoline Gas for country use.

_Send for Illustrated Catalogue._

=ECONOMIC MOTOR CO.,
Office and Salesrooms 34 Dey St. N. Y.=

PIPE COVERINGS

Made entirely of ASBESTOS.

=Absolutely Fire Proof. BRAIDED PACKING, MILL BOARD, SHEATHING, CEMENT, FIBRE AND SPECIALTIES. CHALMERS-SPENCE CO., FOOT E. 8TH ST., N. Y.=

SHIELDS & BROWN

Manufacturers and Sole Proprietors of

=For BOILERS and STEAM PIPES
Reduces Condensation of Steam.=
FOR GAS AND WATER PIPES.
=Prevents Sweating and Freezing.=
=The Best Non-Conductor of Heat and Cold in the World=
Send for illustrated descriptive Circular, and name this paper.
=143 Worth Street, New York.
78 and 80 Lake Street, Chicago.=

VIOLIN OUTFITS.

Consisting of Violin Box, Bow, and Teacher, sent to any part of the United States on 1 to 3 days' trial before buying.

=Violin Outfits at $4, $8, $15 and $25 each. Send Stamp for= Beautiful Illustrated 96-page Catalogue of Violins, Guitars, Banjos, Cornets, Flutes, Strings, etc. Lowest prices. Mail orders a specialty. =C. W. STORY, 26 Central Street, Boston, Mass.=

ICE HOUSE AND COLD ROOM.--BY R. G. Hatfield. With directions for construction. Four engravings. Contained in SCIENTIFIC AMERICAN SUPPLEMENT, =59.= Price 10 cents. To be had at this office and of all newsdealers.

HARTFORD STEAM BOILER
HARTFORD. CONN.
INSPECTION AND INSURANCE CO.

OPERA GLASSES

_Microscopes, Telescopes, Spectacles, Barometers, Thermometers, Photographic Outfits for Amateurs,_ =W. H. WALMSLEY & CO.= successors to R. & J. Beck, Philadelphia. Illus. Price List free to any address.

Bibb's Celebrated Original BALTIMORE FIRE-PLACE HEATERS,

To warm upper and lower rooms. The handsomest, most economical Coal Stoves in the world.

=B.C. BIBB & SON=
Foundry Office and Salesrooms,
39 and 41 Light Street,
Baltimore, Md.
MARBELIZED SLATE MANTELS.
_Send for Circulars._

THE BOOMER & BOSCHERT PRESSES.

We make a great variety of Presses, with powers from 50 to 700 tons, with movement of platens from one inch to six feet or more, to work by hand or power, and at any speed required. Send for catalogue.

BOOMER & BOSCHERT PRESS CO.

155 WEST WATER STREET, SYRACUSE, N. Y., U. S. A.

THE AMERICAN BELL TELEPHONE CO.

95 MILK ST., BOSTON, MASS.

This Company owns the Letters Patent granted to Alexander Graham Bell, March 7th, 1876, No. 174,465, and January 30th, 1877, No. 186,787.

The transmission of Speech by all known forms of Electric Speaking Telephones infringes the right secured to this Company by the above patents, and renders each individual user of telephones not furnished by it or its licensees responsible for such unlawful use, and all the consequences thereof, and liable to suit therefor.

SHEPARD'S NEW $60 Screw-Cutting Foot Lathe.

Foot and Power Lathes, Drill Presses, Scroll-saw Attachments, Chucks, Mandrels, Twist Drills, Dogs, Calipers, etc.

Lathes on trial. Lathes on payment.

Send for catalogue of Outfits for Amateurs or Artisans.

=Address H. L. Shepard, Agent, 134 E. 2d St., Cincinnati, O.=

PULLEYS.

Order from our "Special List." THE JOHN T. NOYE MFG. CO., BUFFALO, N. Y.

PROSPECTUS

OF THE

Scientific American FOR 1887.

The Most Popular Scientific Paper in the World.

Only $3.00 a Year, including Postage. Weekly. 52 Numbers a Year.

=This widely circulated= and splendidly illustrated paper is published weekly. Every number contains sixteen pages of useful information and a large number of original engravings of new inventions and discoveries, representing Engineering Works, Steam Machinery, New Inventions, Novelties in Mechanics, Manufactures, Chemistry, Electricity Telegraphy, Photography, Architecture, Agriculture, Horticulture, Natural History, etc.

=All Classes of Readers= find in the SCIENTIFIC AMERICAN a popular _resume_ of the best scientific information of the day; and it is the aim of the publishers to present it in an attractive form, avoiding as much as possible abstruse terms. To every intelligent mind, this journal affords a constant supply of instructive reading. It is promotive of knowledge and progress in every community where it circulates.

=Terms of Subscription.=--One copy of the SCIENTIFIC AMERICAN will be sent for _one year_--52 numbers--postage prepaid, to any subscriber in the United States or Canada, on receipt of =three dollars= by the publishers; six months, $1.50; three months, $1.00.

=Clubs.--One extra copy= of the SCIENTIFIC AMERICAN will be supplied gratis _for every club of five subscribers_ at $3.00 each; additional copies at same proportionate rate.

The safest way to remit is by Postal Order, Draft, or Express Money Order. Money carefully placed inside of envelopes, securely sealed, and correctly addressed, seldom goes astray, but is at the sender's risk. Address all letters and make all orders, drafts, etc., payable to =MUNN & CO., 361 Broadway, New York.=

THE Scientific American Supplement.

This is a separate and distinct publication from THE SCIENTIFIC AMERICAN, but is uniform therewith in size, every number containing sixteen large pages. THE SCIENTIFIC AMERICAN SUPPLEMENT is published weekly, and includes a very wide range of contents. It presents the most recent papers by eminent writers in all the principal departments of Science and the Useful Arts, embracing Biology, Geology, Mineralogy, Natural History, Geography, Archæology, Astronomy, Chemistry, Electricity, Light, Heat, Mechanical Engineering, Steam and Railway Engineering, Mining, Ship Building, Marine Engineering, Photography, Technology, Manufacturing Industries, Sanitary Engineering, Agriculture, Horticulture, Domestic Economy, Biography, Medicine, etc. A vast amount of fresh and valuable information pertaining to these and allied subjects is given, the whole profusely illustrated with engravings.

_The most important Engineering Works_, Mechanisms, and Manufactures at home and abroad are represented and described in the SUPPLEMENT.

Price for the SUPPLEMENT for the United States and Canada, $5.00 a year, or one copy of the SCIENTIFIC AMERICAN and one copy of the SUPPLEMENT, both mailed for one year for $7.00. Address and remit by postal order, express money order, or check.

=MUNN & Co., 361 Broadway, N. Y.,=

Publishers SCIENTIFIC AMERICAN.

=To Foreign Subscribers.=--Under the facilities of the Postal Union, the SCIENTIFIC AMERICAN is now sent by post direct from New York, with regularity, to subscribers in Great Britain, India, Australia, and all other British colonies; to France, Austria, Belgium, Germany, Russia, and all other European States; Japan, Brazil, Mexico, and all States of Central and South America. Terms, when sent to foreign countries, Canada excepted, $4, gold, for SCIENTIFIC AMERICAN, one year; $9, gold for both SCIENTIFIC AMERICAN and SUPPLEMENT for one year. This includes postage, which we pay. Remit by postal or express money order, or draft to order of

MUNN & CO., 361 Broadway, New York.

PRINTING INKS.

The "Scientific American" is printed with CHAS. ENEU JOHNSON & CO.'S INK. Tenth and Lombard Sts., Phila., and 47 Rose St., pop. Duane St., N. Y.

[Transcriber's Note:

Inconsistent spelling and hyphenation are as in the original.]