1892.] MICROSCOPICAL JOURNAL. 193 



Through the centre of the cover of boiler is an opening, which 

 answers as a receiver for a thermometer whose scale is divided 

 from 120° to 320° F. A layer of absorbent gauze covering the 

 perforated bottom prevents boiling water to come in direct con- 

 tact witli substance to be sterilized and completes the apparatus. 

 A tripod and frame containing an alcohol lamp with (4) four 

 burners accompanies the sterilizer in the event that a stove or gas 

 or oil burner is objectionable. With eight ounces alcohol a tem- 

 perature of from 210° to 312° F. for two hours can be obtained. 

 The above illustration shows the apparatus ready for use. 



Zentmayer's American-Continental Stand. — This stand 

 has been designed to meet the wants of those workers who prefer 

 the compact Continental model and yet are conscious of its in- 

 herent defects. It is substantially a combination of the upper 

 half of our celebrated American stands with the lower half of the 

 best Continental stands, and is adapted to have added all the 

 usual optical accessories of either class of microscopes. As 

 offered, it answers fully every want of the class-room or labora- 

 tory at ver}- moderate cost. 



The stand is constructed entirely of brass, handsomely finished 

 and polished. The base is of horseshoe form, filled with lead 

 for extra weight, and gives perfect steadiness in every position. A 

 stout pillar firmly supports the arm of the instrument on a trun- 

 nion-joint, which allows all inclinations from the perpendicular 

 to the horizontal posftion. The coarse and fine adjustments are 

 of the same style and construction as the famous Centennial stand. 

 The arm carrying the body is provided with two slides, the upper 

 and longer one bearing the tube with rack and pinion movement, 

 and sliding in the low^er one, wdiich is controlled by a lever of the 

 second order, operated by a milled-headed micrometer sci^ew in 

 convenient position at the back of the instrument. At the bottom 

 of the lower slide there is a shoulder against which the lever acts, 

 and a spring above presses down against this shoulder, insuring 

 its continuous contact with the lever during adjustments. All the 

 mechanism is concealed within the arm, which is so hollowed as 

 to secure both lightness and greater rigidity. This fine adjustment 

 is free from lateral motion, and exceedingly sensitive. Its con- 

 struction prevents wear, and is so positive that a revolving nose- 

 piece and attached objectives can be easily carried without injury. 

 It also acts as a safety appliance in case an objective is accident- 

 ally racked down against an object, for the spring yields quickly 

 to upward pressure. The body-tube is five and one-half inches 

 long, with draw-tube extending full ten inches, thus giving both 

 English and Continental standards, and accommodating objectives 

 corrected for either length. The stage is made of aluminum, 

 which is incorrodible ; the dimensions (three and five-eighths 

 inches square) are commodious even for culture slides or serial sec- 

 tions ; the surface is plane, with recessed opening to receive a 

 glass plate, light modifier, or disk-diaphragm, if wanted; re- 

 movable clips are provided with springs shaped and adjusted to 



