82 



THE MICROSCOPE AND ITS REVELATIONS. 



made by the milled-liead; and thus even high powers may be very con- 

 viently worked. The legs being tubular, one of them is made to hold 

 glass dipping-tubes, whilst the other contains needles set in handles, with 

 three short legs of steel wire, by screwing which into the stem and stage, 

 the Microscope may be used (though not without risk of overturn) in the 



vertical position. This in- 

 strurnent may be specially 

 recommended to those who, 

 already possessing a superior 

 Microscope, desire neither to 

 encumber themselves with it 

 whilst travelling, nor to ex- 

 pose it to risk of injury, but 

 wish to utilize its Objectives 

 by means of a simple and 

 portable arrangement. 1 



79. Swift's Portable Bin- 

 ocular. Carrying still further 

 an idea originally worked-out 

 by Messrs. Powell and Lea- 

 land, Mr. Swift has devised 

 a very complete Portable Bin- 

 ocular, which can be folded 

 into a very small compass, 

 without any screwing or un- 

 screwing, and can be thus set 

 up, as in Fig. 55 A, or packed 

 away, as at Fig. 55 B, with 

 great facility, when once the 

 manner of doing so has been 

 learned. Its construction is a 

 marvel of ingenuity; while its workmanship is so excellent that its joints 

 do not easily become loosened by wear, and can all be readily tightened 

 when required. It is so steady as to bear being worked (as a Monocular) 

 with even high powers; but its great advantage consists in its suitability 

 to the Traveller, who either wishes (as often happens to the Author) to 

 display to scientific friends in other countries a set of objects that can be 

 most advantageously seen by the Binocular under low powers, or to avail 

 himself of opportunities of examining on the spot any interesting speci- 

 mens he may meet with. The instrument also carries Mr. Swift's 

 Combination Sub-stage (Fig. 85), which can be packed, together with 

 three Objectives, Side-Condenser, and several other Accessories, into a 

 Case only 11 inches long, 6J inches wide, and 3-J inches deep, the whole 

 weighing only 7^ Ibs. 



80. Nachet's Chemical Microscope. The inverted Microscope origi- 

 nally constructed by MM. Nachet on the plan devised by I)r. J. Lawrence 

 Smith, of Louisiana, U.S., for the purpose of viewing objects from their 

 under side when heat or re-agents are being applied to them, 2 has lately 

 been improved by its constructor with a special view to meeting the re- 

 quirements of observers engaged in the ' cultivation ' of the minute organ- 



1 Instruments nearly resembling the above are made by Messrs. Murray and 

 Heath, Mr. Browning, and Mr. Swift. 



2 This idea was suggested at nearly the same time by Dr. Leeson; and was 

 carried out in an instrument constructed for him by Messrs. Smith and Beck. 



Baker's Travelling Microscope. 



