132 



ENGINEERS' 18 inch WYE LEVEL. 



Leveling Instrument of Precision. 



Eighteen or seventeen-inch powerful telescope; aperture of object-glass 1 3 

 inches in diameter; eye-piece provided with an improved .s-creio arrangement for the 

 accurate focussing of cross-wires ; field of view large and Hat; telescope provided 

 with an adjustable stop to readily set cross-wires horizontal and perpendicular ; line, 

 ofcollimation true on all distances; objects erect; telescope balanced each way from 

 the center whenfocussed to a mean distance with sun-shade attached to it to secure the 

 highest accuracy attainable ; telescope rings and the center are very stout, long 

 and of the hardest bell-metal; cross-bar is cast hollow and provided with ribs; 

 8-inch very sensitive spirit level ; instrument does not detach from tripod above 

 leveling screws; it packs whole and stands in the case erect. Mahogany case, 

 provided with straps, and hooks, contains sun-shade, wrench, screw driver, and 

 an adjust ii'ir pin. 



Weight of instrument 11 Ibs., weight of tripod from 7 to 7^ Ibs. 



Gross weight of instrument, packed securely for shipment in two boxes, about 

 48 Ibs. 



Price, including a protection to the object-slide, .... $14O.OO. 



Telescope and level tube will be cloth-finished, unless ordered to the contrary 

 when an extra charge of $5.00 will be made. However, we strongly advise the 

 cloth-finish. (See cloth-finish.) 



Extras to Engineers' Wye Level. 



Center of instrument made of steel, and hardened, and running in a socket 



of cast iron, improved style J ( See cut on opposite page ) . . . Sl~>.(>n 



Stadia wires, fixed :'..oo 



Short Focus Lens (see pages 118, 169) one pair ...... Ki.oo 



Metal-mirror with universal joint. (This is readily attachable to the instru- 

 ment and facilitates the reading of the bubble on soft ground without 

 stepping aside.) ........... 10.00 



Kxtra Sun-shade with smaller aperture, for use with the telescope when 



the sun's rays are too bright for accurate work, ... . 1.50 



Instrument provided with three leveling screws, as shown in cut of Hydro- 



grapher's Wye Level,* 18.00 



Gossamer water-proof bag, to protect the instrument in case of rain or dust, 1.00 

 Bottle of fine watch oil, to lubricate the level center, 0.25 



* Four leveling screws commend themselves in the more ordinary class of instruments for the greater 

 rapidity with which an instrument can be leveled up approximately and that (no matter how much the levelling 

 screws may be worn) when brought to a true bearing on the lower leveling plate, all such looseness is taken up. 



NO. 2. ENGINEERS' 14 inch WYE LEVEL. 



No. 2. The essential features of this instrument are like those enumerfif{ 

 tbove, and shown in cut of eighteen-inch Engineers' Wye Level, with the except ion 

 > and weight. It is designed to be used in cases irfiere a lighter instrument 

 Is desirable. It is provided with a i'ourt ecu-inch telescope which has an a pert ure of 

 1% inches in diameter and a power of 27 diameter ; six inch sensitive spirit-level; 

 bell center; four leveling screws. 



Weight of instrument, 9 Ibs.; weight <>t' tripod, from fii^ to 7^ Ibs. 



Gross weight of instrument, packed securely for shipment in two boxes, ai>out 

 ) Ibs. 



^ inciting a protection to the object-slide, ..... $|;SO.OO 



renter df instrument made of steel, and hardened, and runninir in a socket 



of cast iron, improved style | see cut on opposite p;ti:c i . . . ].">. oo 



t Steel Centers. Although the centers of our Wye Levels, which are limp; and unyu Iding, to afford 

 SteadinCM, are giving high satisfaction, inasmuch as they are made of very hard hell-metal (nearly equal to 

 soft Bteel), in order to revolve with a minimum of friction, we also make them, when so ordeicd, of *:,,/ t<> 

 run in a socket of hard cast-iron. Jn using these two latter metals whose co-efficirnt of expansion is nearly 

 alike, the same condition as to a free motion in all temperatures obtains, whether below /ero 01 



is with "ur h.ml l>-ll-mrtal center running in a socket of brass composition, with the difference, how- 

 ever, that tin; steel ones will retain their precise fitting qualities so wo 11 that the bubble of the tcK 

 spirit level will hardly show any displacement upon revolving the instrument when leveled up, even alter 

 years of constant servite. In order to make our superior steel center and cast iron socket construction a 

 standing feature in our Wve Levels, we placed the cost at a nominally high-'r pri( e only, although the cost of 

 production to us is more than double that of the customary style of steel center. We strongly advise to order 

 it where first greater outlay is not considered as important' as greater wearing qualities. 



