ADDENDA TO LIST 



OF 

 CONSTRUCTED BY 



ANDREW PBITCHARD, 



©[pTQga^K] aim© g^gTaeii B^iAiKnyjiFAigTr^siiigg 



162, FLEET STREET, LONDON. 



1. Pritchard's Apparatus for illustrating the Interference of Light, with 



Telescope and 100 Screens s ' \^ 15 15 () 



I" - ditto, with 50 Screens .. .. .'.' "' ' jq 10 q 



^' ditto Pocket Apparatus . . . . . ' 8 6 



4- ~ improved Eye-piece Polariscope, with Reflector ' .'. 2 2 



th^Jth! w- 8 i rU1 £ e ? t exhibits . the col °i"-s more intense, and the rings better denned 

 than the Slider Polariscope, invented some years ago by Mr. P. and now eeneraHv 

 used. It can be applied to any compound Microscope. generally 



■ improved Polarizing Apparatus for the Microscope . . Ill g 



»„a ? y Mr * P "' S " ew "'•'"'ge'pent of the Prisms, the field of view is greatly extended 

 and any eye-piece can be used. gieauy e.\ienuea, 



— — — ditto ditto large Prisms and a double image one . . 4 4 

 lhe Apparatus §4 and 5 fitted to Microscopes . 9 ,., , 



8. Stereoscopes " K f) 



10 SwH^f 111 Spri , ng ^ C1 °, C r' f ° rfixing the SUn ' S ima & e in any position 8 8 

 iu. Fntchards improved Gas Microscopes .. .. .. "=£18 to 



}}; ~ ditto di "p with polarizing and interference Apparatus 



l ~- new portable Gas Generators and Holders , 



andSaL?^ 



13. Prism Telescopes for shewing the lines in the Spectrum 



14. Pntchard s Vertical Microscopes, single, doublet and triplet £5 5s. to 10 10 



not SLXJBLK! **** "' *" const ™ ted "ith thin piano, convex lenses, and 



U\ T -—Achromatic Microscopes [see Microscopic Illustrations] ^15 to 



16. Improved Magic and Phantasmagoria Lanthorns. . £1 12s. 63 and 



Sliders of Astronomical, Natural History, Costume, and Comic subjects. 



17. Selenite Ornaments and Wedges for polarized Light 7 

 Jo S ail L S ?/ LenS6S f ? r exhibit ing Newton's coloured Rings .' .' 10 

 on p v i s ™P roved , dum Py single-image Prisms, each . . 7s. 6d. to 14 



20. Pritchard's new Fine-Adjustment Microscope Bodies .. . ni 



f ^„ This construction is simple, more precise in its action, and of more eeneral utilitv 

 than any contrivance yet invented for the purpose. general utility 



21 . Microscopic Objects, Is. each and upwards, or in cases at 6s., 15s., 21s.and 



These objects consist of thin sections of Recent and Fossil Woods Coal let PW 



22. Specimen Cases, containing Examples of the above, each 8s. 6d. and 15 



ACHROMATIC AND REFLECTING TELESCOPES. 



OPERA GLASSES, Single, Double, and Solid. 

 SPECTACLES IN EVERY VARIETY OF MOUNTING, W.TH CRYSTAL AND CLASS LENSES. 



ie) is aw s ss'® EissmTm,wwmi^T^ a 



BAROMETERS AND THERMOMETERS. DOUBLE IMAGE PRISMS 



njEOMW RHOMBS. BARTON* IR1 S BUTTONS. TOURMALINES. POLISHED CALCAREOUS SPAR 



INTERFERENCE MIRRORS AND PRISMS. 



^alamwg anir iflurosfroptc Styparattt* of all femoa. 



} - Darkirr, Primer, s, Uruve Cottages, H jllowsy. 



8 8 I) 



7 7 n 

 



3 13 



5 5 



