OF SURVEYING INSTRUMENTS. 59 



FIG. 3G6. 



360. Theodolite, 3-inch, of the most approved construction, reading to one minute 

 divided on silver, in mahogany case, with tripod stand, complete 18 



362. THEODOLITE, 4-inch., ditto, ditto 19 10 



363. 4-inch., ditto, with two telescopes . . 24 



364. 5-inch., ditto, with one telescope . . . 22 10 



365. 5-inch., ditto, with two telescopes. . . 27 



366. 6-inch., verniers reading to 20 seconds, divided on silver, in 

 mahogany case and tripod stand, complete (fig. 366) . 28 10 



367. Theodolite, 6-inch., ditto, with two telescopes . . 34 10 



368. 7-inch., with extra large telescope, verniers reading to 10 seconds, 

 divided on silver, with case and stand as above . . 35 



369. THEODOLITE, 7-inch., ditto, with two extra large telescopes . 44 

 *#* The above Nos. 360 to 369 if with locking plate and tripod screw adjustment (a,sfig. 375), 



instead of the usual parallel plates are for the 3 inch., 22s., 4 inch., 30s., 5 inch., 45s., 6 inch., 

 60s., 7 inch., 75s. each extra ; and if divided on the brass circles instead of on silver, 3 inch., 

 22s., 4 inch., 30s., 5 inch., 37s., 6 inch., 45s., 7 inch., 60s. each less in price. 



370. The Traveller's Transit Theodolite, arranged by L. CASELLA as a small light 



portable instrument for Alpine and military surveying, and occasional 

 astronomical observations. In designing this instrument the object has been 

 to condense into the least possible bulk the smallest instrument with which 

 useful results can be obtained. Its telescope gives it the advantage of optical 

 power, and it has complete 3-inch, circles, both horizontal and vertical, with 

 verniers showing to one minute ; it can therefore be used not only as a 

 theodolite for terrestrial surveying, but also as an altazimuth for determining 

 time, latitude, and azimuth, astronomically. It will be found convenient in 



