IV. CALORIMETKY. 271 



The body to be studied is placed in a small metallic basket suspended in 

 the middle of the central tube of the stove ; a thermometer indicates the tem- 

 perature of this part of the apparatus. When the moment has come for 

 bringing down the body into the calorimeter the screen must be lifted up, and 

 the carrier which supports the thermometer made to slide on the copper guide 

 until it reaches a certain point fixed on the guide. With one hand the basket 

 is let slip, and with the other the detent of a rapidly acting spring appliance 

 is released. The body being thrust into the calorimeter it must be brought 

 back to its former position and the screen then lowered. This apparatus, 

 which is easily worked, enables M. Regnault's experiments on this subject to 

 be repeated most accurately. 



1058c. Jamin's Calorimeter. L. Golaz, Paris. 



This instrument, made for the designer, is constructed on the same principle 

 as M. Favre's, but being only used for demonstrations its construction is 

 simpler. It consists of a cylindrical vessel of glass, provided with an iron 

 cover to which are fixed two iron tubes reaching down into the cylinder, the 

 stern of the thermometer being placed vertically in the cover. A small glass 

 funnel is placed over a stop-cock terminating in a capillary glass tube, which 

 serves for filling the apparatus. 



lOSSd. Bunsen's Absorptiometer. L. Golaz, Paris. 



This apparatus consists of a wooden stand, to which is fixed an iron ring 

 carrying two yertical supports, united at the top by a circle to which is fixed 

 a plate on hinges. Along one of the columns is placed an iron tube, having 

 at its upper end an iron funnel ; at the lower it enters the vertical opening, of 

 a three-way cock. One of the horizontal openings communicates with a 

 chamber made in the centre of the stand, and the other communicates with 

 an outlet; thus it is possible either to make the mercury run into the 

 chamber, or, by turning the cock another way, to permit it to escape. 



On the upper surface of the wooden stand has been made a deep groove, at 

 the bottom of which is fixed a washer of vulcanized india-rubber. A glass 

 cylinder, the ends of which are perfectly true, rests in this groove, and fits 

 the top of the stem ; the plate, which is used as a cover, is provided with an 

 india-rubber disc, and rests on the top of the glass cylinder. 



The absorption-tube is open at its lower end, and cemented into a socket 

 made of iron, having a screw thread which fits into an iron block cut away at 

 the sides. A rotary motion about its axis is sufficient to cause the opening 

 or closing of this tube, an india-rubber washer being placed at the junction. 



On the part of the block which is not cut away are fixed two springs of 

 steel, which retain it in the hollow of the stand and in two diametrically 

 opposite grooves which are placed there ; a slight friction is thus produced, 

 permitting however the opening and shutting of the absorption tube. At the 

 centre of the higher plate of the cover is an iron socket on which is stretched, 

 by means of a ring screwed to it, a piece of india-rubber ; in lowering the 

 cover the point of the tube enters into the socket, and the tube is found per- 

 fectly fixed at the centre. 



1058e. Regnault's Air Thermometer. L. Golaz, Paris. 



This apparatus is composed of a glass cylinder terminating in a capillary 

 stem bent at right angles, and supported by a metal stand, having in its 

 centre a tube on which is placed the stem of the thermometer. The screw 



