1900] MICROSCOPICAL JOURNAL. 279 



tweea the water and the spherical balls. It cannot es- 

 cape downwards and therefore it escapes upwards, and 

 doing it, it escapes on one side of the ball which is thus 

 pushed to the opposite side. This it does until it is stop- 

 ped by striking against the containing vessel. There it 

 goes up hill, for the water goes uphill itself by capillary 

 attraction. When it has gone up hill until it meets the 

 side of the vessel it tends to roll down again and it is 

 urged on by the escaping hydrogen only to go up hill on 

 the opposite side of the vessel, and so the motion goes on 

 until it is all dissolved and the motion ceases. In this 

 mode, motion starts and is communicated to the sodium 

 oxide. The motion seems to belong to the globule but it 

 is not so. 



A New Exhibition Microscope. 



In accordance with the original suggestion, and by the 

 generosity of Mr. Wm. E. Dodge, of the Board of Mana- 

 gers, the Garden has-been able to place in position, in the 

 systematic museum, a permanent microscopical exhibit in- 

 cluding twenty-five microscopes of special design. 



The Leitz stand V is used in the construction of these 

 instruments. The foot is removed and the upright sup- 

 port fastened to a base of hardwood 6 x 6 x 1 in. blacken- 

 ed and with beveled edges. The mirror swings in two 

 axes, and the square stage is furnished with awheel dia- 

 phragm. The whole stand is surrounded by a case made 

 of sheets of plate glass cemented at the joints. The out- 

 side measurements of the case are 4| x 4f x 6 in. The top 

 of the case is not cemented but is held in place by four up- 

 right rods which pass down through the base and are fast- 

 ened by nuts, both on the lower side of the base and on 

 the upper side of the top. 



The instrument is furnished with fine adjustment only, 

 and the milled head is removed, allowing the top of the 

 case to rest on the head of the support. The square head 



