How to Catch and Preserve Moths and Butterflies.--Practical directions for collectors. 10275 The Clavi Harp.--A new instrument, a harp played by means of keys arranged on a keyboard--1 illustration. 10275 Inquiries Regarding the Incubator.--By P.H. JACOBS.--Notes concerning the incubator described in a previous issue (SUPPLEMENT, No. 630).--Practical points. 10265 IX. PHYSICS.--The Direct Optical Projection of Electro-dynamic Lines of Force, and other Electro-dynamic Phenomena.--By Prof. J.W. MOORE--Second portion of this profusely illustrated paper, giving a great variety of experiments on the phenomena of loop-shaped conductors.--26 illustrations. 10272 The Mechanics of a Liquid.--An ingenious method of measuring the volume of fibrous and porous substances without immersion in any liquid.--1 illustration. 10269 X. PHYSIOLOGY.--Artificial Mother for Infants.--An apparatus resembling an incubator for infants that are prematurely born.--Results attained by its use.--1 illustration. 10274 Gastrostomy.--Artificial feeding for cases of obstructed oesophagus.--The apparatus and its application.--2 illustrations. 10274 XI. PHOTOGRAPHY.--How to Make Photo-Printing Plates.--The process of making relief plates for printers. 10271 XII. TECHNOLOGY.--Improved Current Meter.--A simple apparatus for measuring air and water currents without indexes or other complications.--1 illustration. 10270 The Flower Industry of Grasse.--Methods of manufacturing perfumes in France.--The industry as practiced in the town of Grasse. 10270 Volute Double Distilling Condenser.--A distiller and condenser for producing fresh water from sea water.--3 illustrations. 10269 The Argand Burner.--The origin of the invention of the Argand burner. 10275 * * * * * [Illustration: THE CROWN PRINCE OF GERMANY--PRINCE WILLIAM AND SON [From a Photograph]] THE CROWN PRINCE OF GERMANY--PRINCE WILLIAM AND HIS SON.