48 L. CASELLA'S CATALOGUE 



points being marked upon each tube, the stems are coated with black, or immersed 

 in a preparation of hot wax, the tube is then laid upon the engine, the distances of 

 the respective marks calculated and arranged. On setting the engine the divisions 

 are then made on the wax with the dividing needle with mathematical precision, 

 by turning a wheel and shifting and re-arranging the tube from time to time. 

 The tube being then immersed in a preparation of fluoric acid for a few seconds, 

 the divisions are thus etched in, the tube is then washed in water and the wax removed, 

 after which the marks are filled in with a preparation of black. Another great im- 

 provement consists in the use of porcelain slips or scales. The divisions on these are 

 first made on a coating of wax or black, as in the case of the tubes, then cleaned off, 

 and painted together with the figures, and permanently burnt in, whilst an improved 

 preparation of porcelain has been arranged by L. CASELLA, by which they are rendered 

 impervious to all the influences of dyes or coloring-matters, or changes arising from 

 frost or moisture when exposed to the weather. 



DRAWING-ROOM AND HOUSE THERMOMETERS. 



Drawing-room Thermometers^ ivory, on ebony or boxwood, double scales, i.e., 

 graduated according to Fahrenheit and Reaumur, or Centigrade, with enamel 

 tubes and German silver mountings ; very neat and easily read. 



192. 6 inch. . . 0661 194. 8 inch. . . 090 



193. 7 inch. . . 7 6 | 195. 10 inch. . . 12 6 

 *#* Where no particular Mnd of graduation is ordered, Fahrenheit in the plainer kind, and 



Fahrenheit and Centigrade in the better kinds of thermometers is usually sent. 



196. Drawing-room Thermometers, ivory scales upon papier mdche, in various 



colors, black, blue, or green, of various shades, very neat, double graduations, 

 viz., Fahrenheit and Reaumur, De Lisle or Centigrade (fig. 196, p. 50), 

 seven inch., 9s. 6d. ; eight inch. .... 10 6 



197. DRAWING-ROOM THEEMOMETEES, polished boxwood, elliptic form, bevelled edges, 



very neat, with German silver or fancy mountings, graduations as above, 

 eight inch, 4s., ten inch, 6s. 6d., twelve inch (fig. 197, p. 50) 096 



An excellent and cheap thermometer, very suitable for libraries, churches, etc. 



198. Drawing-Room Thermometer divided into half-degrees, very sensitive, with 



mountings, etc., as above, twelve inch . . . 14 



199. DRAWING-BOOM THERMOMETER, eleven inch, on opal, mounted on ebony, with 



plain clear black figures and divisions, bold and very handsome 16 



200. DRAWING-ROOM THERMOMETER, on opal and mahogany, as above 16 



201. Boxwood Thermometer polished, for ordinary use, double scale and enamel 



tube, 8 inch. , V, 030 



202. BOXWOOD THERMOMETER, eight inch, plain, good, and reliable, well adapted for 



bed-booms, pantries, wine cellars, etc. . . . 18s. per dozen 



Or, if less than 3, Is. 8d. each. 



203. Six's Self-.Registering Thermometers for wine cellars, greenhouses, etc., to show 



present temperature and register the past extremes of heat and cold during any 

 period of absence, in japan case with magnet, 8 in., 12s. 6d. ; 10 in. 15 6 



204. Six's THERMOMETERS, as above, 12 in., 18s. 6d. ; 14 in. . 110 



