CHEMICAL LABORATORY AT THE UNIVERSITY OF SYDNEY. 177 

 PRIVATE LABORATORY. 



There is nothing very special in this room, excepting that an 

 effort has been made to make the most of a limited space — it 

 provides accommodation for three or four workers. 



The glass hood between the windows is unprovided with sashes 

 and upriglits, so as to leave the bench as clear as possible. The 

 draught cupboard, eighteen feet long facing the windows 

 (Plate XIV.) is supported on slate slabs, and is fitted with 

 water-ovens, water-baths, hot plates, &c. 



WORKING BENCHES. 



Efforts have been made to combine the best features of those 

 in use in other laboratories, and where possible to improve upon 

 them. Shelves for re-agents are omitted altogether from the 

 benches (Plate IX.) in the junior students' laboratory, and their 

 place is supplied by moveable rack-trays, saturated with paraffin 

 wax to prevent the action of acids. The shelves, as ordinarily 

 arranged, obstruct the view of the laboratory, aiid they not only 

 hide the students from the instructors, but what is of moi^e 

 importance, they hide the instructors from the students. It is 

 most desirable that the students should be able to see the 

 instructors from all parts of the room, so that they may be able 

 to go to them for information at once, and without any unnecessary 

 expenditure of time. There is, moreover, the additional advantage 

 that fewer instructors ai'e required. 



The moveable racks for re-agents are less obstructive in other 

 ■ways and occupy less space, since, when not required, they can be 

 put away in the cupboard under the benches, thus leaving all the 

 table top free for bulky apparatus — an important matter in the 

 student's early work — when engaged upon experiments with the 

 gases, afterwards when testing, the space occupied by the racks 

 can easily be spared. At night they can be placed in the cupboard 

 under lock and key. 



The benches in the general laboratory (Plate VII.) are made 

 fairly complete and convenient without being luxurious. Each 

 student has the usual gas and water supply for working and 

 distillation, and the use of one aspirator tap on the bench, and often 

 of two. The sulphuretted hydrogen supply is to be brought to 

 each bench from a gas-holder out of doors through ordinary small 

 composition gas-piping, and in the draught cupboai'd this is 

 finished off" with a piece of three-quarter inch copper tubing for 

 the insertion of a glass or ebonite tap (of small bore, one-eighth 

 inch to one-twelfth inch, to prevent waste) through a perforated 

 cork. By this means all permanently fixed metal taps are done 

 away with — metal ones are objectionable from their liability to 

 corrode and become fast. If an I.R. pinch-tap be used, the wide 

 copper end is unnecessary. Although the central water-taps and 

 sink are liable to be a source of splash and wet on the bench, 

 M 



