PREFACE. 



The object of this treatise is to point out to teachers of physical 

 science, and to others who may be interested in experimentation, 

 the usefulness of the IVIagic Lantern, and especially of the Porte 

 Lumiere, and a few other pieces of apparatus which can mostly 

 be extemporized. With these a surprisingly large number of 

 experiments in every department of physics may be performed, 

 and every department of science and art may be illustrated; and 

 the illustrations may be upon a scale of magnitude which will 

 surprise one who has never witnessed them. The manipulation of 

 the apparatus is not at all difficult, and no one need fear he will 

 not succeed in doing anything described in the book, provided that 

 at first he masters the simple conditions of projection with a single 

 lens and with a condenser. 



The simplest fixtures have been described, and a cut has been 

 inserted wherever it could make more intelligible either the forms 

 of the apparatus or the necessary conditions. No attempt has 

 been made to explain phenomena, — other books do that ; but it 

 is hoped that a sufficient number and variety of experiments are 

 plainly described to make anyone thoroughly familiar with the 

 art of projecting. 



