SOME MANUFACTURERS AND DEALERS IN OPTICAL 

 AND PROJECTION APPARATUS AND SUPPLIES 



Within recent years there has been great improvement in projection appara- 

 tus and all the necessary accessories, and many optical manufacturing houses 

 have taken hold of the work in earnest, so that now one can find in the open 

 market practically everything required at reasonable prices. Furthermore, if 

 special apparatus or combinations are desired, or if a person has notions of his 

 own, it is not difficult to obtain the optical and electrical apparatus needed of 

 the manufacturers, and only a small amount of special construction will be 

 needed to adapt the apparatus to the special individual or the special purpose. 



It is hoped that the special apparatus described in this volume, for example, 

 the projection microscope and the projection outfit for showing normal and 

 defective vision, and for some special demonstrations in physics, will give sug- 

 gestions which will open the way for those who do not find the apparatus in 

 the open market quite suitable" to their needs. 



As models of instruments are constantly changing and new forms are being 

 produced, the authors advise that any one desirous of installing projection 

 apparatus of any kind should get the catalogues of several manufacturers and 

 select that which best suits his needs and means. It may be stated in passing, 

 that the most expensive apparatus is not necessarily the best adapted for a 

 given case. Often apparatus of moderate price is easier to manage and more 

 effective. Naturally the manufacturers prefer to install an expensive outfit, 

 but if the needs are clearly stated, and the sum available, the manufacturer 

 will give most excellent advice as to the outfit required. 



The dealers in lantern slides have a system of rental by which one can get for 

 a moderate fee a set of slides to illustrate some special or general subject. Of 

 course, slides of any number or grouping can also be purchased, but often a 

 special lecture on a country or a period can be greatly helped by a good selec- 

 tion of lantern slides, the use of which will cost but a small sum. 



For those interested in moving picture cameras, the development of exposed 

 films, etc., the advertising pages of the Moving Picture World will give the 

 names of the firms who can give the information or the help needed. 



The following list of manufacturers and dealers is arranged alphabetically, 

 and from our experience with them we know that they try to be of real service 

 to their customers. Of course there are many others who are equally reliable; 

 and new manufacturers and dealers are constantly coming into the field. One 

 can get on track of them by consulting the advertising pages of standard 

 periodicals as: Science, the Scientific American, the Moving Picture World, 

 Journals in Electrical and Illuminating Engineering. 



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