[Illustration:  Merryweather’s pumping engine.]

We are indebted to The London Engineer for the engraving and description.

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Some romances and exaggerations of which the Pitch Lake, at Trinidad, has been the subject, are corrected by Mr. Albert Cronise, of Rochester, N.Y.  Its area, height and distance from the sea have been overestimated, and a volcanic action has been ascribed to it which does not really exist.  It is one mile from the landing place, is 138 feet above the sea level, is irregular, approximately round, and has an area of 109 acres.  Its surface is a few feet higher than the ground immediately around it, having been lifted up by the pressure from below.  The material of the lake is solid to a depth of several feet, except in a few spots in the center, where it remains soft, but usually not hot or boiling.  But as the condition of the softest part varies, it may be that it boils sometimes.  The surface of the lake is marked by fissures two or three feet wide and slightly depressed spots, all of which are filled with rainwater.  In going about one has to pick his way among the larger puddles and jump many of the smaller connecting streams.  Each of the hundreds of irregular portions separated by this network of fissures is said to have a slow revolving motion upon a horizontal axis at right angles to a line from the center of the lake, the surface moving toward the circumference.  This motion is supposed to be caused by the great daily change in temperature, often amounting to 80 deg., and an unequal upward motion of the mass below, increasing toward the center of the lake.  A few patches of shallow earth lying on the pitch, and covered with bushes and small trees, are scattered over the surface of the lake.

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The Gardeners’ Chronicle announces that Mr. Fetisoff, an amateur horticulturist at Voronezh, Russia, has achieved what was believed to be impossible, the production of jet black roses.  No details of the process have been received.

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Recent Books.

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Electro-metallurgy.  Electric Smelting and Refining:  The Extraction and Treatment of Metals by means of the Electric Current.  Being the second edition of Elektro-Metallurgie by Dr. W. Borchers.  Translated, with additions, by Walter G. McMillan.  With 3 plates and numerous illustrations in the text. 8vo, cloth. 416 pages.  London and New York, 1897 $6.50

Electro-technical series.  By Edwin J. Houston, Ph.D., and A.E. 
Kennelly, D.Sc.  Ten volumes:  Alternating Electric Currents, Electric
Heating, Electro-Magnetism, Electricity in Electro-Therapeutics,
Electric Arc Lighting, Electric Incandescent Lighting, Electric
Motors, Electric Street Railways, Electric Telephony, Electric
Telegraphy.  Each $1.00