626 



NATURE 



[July 14, 192J 



tilated acid-proof motor, and is transmitted by two 

 parallel lines of shafting hung in ball-bearings along 

 the whole length of the laboratory and in the fitting- 



FiG. 4. — View showing distribution of high- and low-pressure air, hot j 

 and cold water, steam, vacuum, and gas services, with fitting-shop at j 

 back. ! 



«hop beyond. Resting on the shaft-brackets are the [ 

 iTiain pipes (showing through the lattice girder in ' 

 Fig. 4) of the seven principal ser- 

 vices : — Steam, 8o-lb. air, lo-lb. air, 

 vacuum, hot and cold water, and 

 gas. 



Both higli- and low-pressure air 

 are obtained from the same com- 

 pressor (Fig. 5), which, by an ap- 

 propriate arrangement of blow-off 

 ■and reducing valves, delivers into 

 two separate receivers at the 

 required pressures. From these the 

 air is led through high- and low- 

 pressure mains to all parts of the 

 laboratory, the former main being 

 in permanent connection with the 

 mild steel (lead lines) liquor re- 

 ceivers from which the filter- 

 presses are charged, and the latter 

 with most of the other apparatus in 

 the laboratory ; for it is the low- 

 pressure air which is put to such 

 general uses as blowing liquor from 

 •one vessel to another, stirring 

 where mechanical stirring is incon- 

 venient, blowpipe work, and so on. 



The main vacuum pump (Fig. 5, 

 at back), which exhausts a 40-gallon 

 \'acuum chamber to the vapour ten- 

 sion of water in about two minutes, 

 is used not onlv for "sucking" the 

 contents of open-top vessels into the liquor tanks, but 

 also for vacuum distillation and for exhausting the 



vacuum drying ovens, which, however, are connected 

 in addition to a small pump capab'e of maintaining 

 a vacuum, once established in the ovens, for any 

 length of time. 



Steam, gas, and cold water enter the laboratory 

 from without. Hot water is obtained by passing 

 water and steam through Mather and Piatt unit 

 heaters, which raise the water to the boiling point 

 as quickly as the pressure in the mains is able to 

 force it through the delivery pipes. 



The types of apparatus permanently fixed in the 

 laboratory are intended to render possible on the 

 greater scale all ordinary chemical operations. The 

 digestors, for example (Figs. 3 and 4), include vessels 

 suitable for nitration, sulphonation, fusion with 

 alkalis, acid and alkaline reduction, acid and alkaline 

 hydrolysis, esterification — in fact, almost every opera- 

 tion which in an ordinary laboratory one associates 

 with a flask on a sand-bath. Heating under pressure 

 is performed in gas-fired heavy mild steel autoclaves. 

 The stills include an apparatus for distillation in a 

 current of saturated or superheated steam, a gas-fired 

 still with a Young's column, a vacuum still with an 

 arrangement of receivers equivalent in its use to the 

 Perkin triangle, and a pan for vacuum evaporation. 

 The redwood tubs on the platform are fitted with 

 stirring gear, and arranged suitably for such 

 operations as diazotisation and coupling and for 

 washing solid precipitates and oils ; they are the 

 beakers and separating funnels of the laboratory. 

 .\pparatus for the three chief methods of filtration, 

 under pressure by filter-presses (on platform, Fig. i), 

 by vacuum in box-filters (Fig. i, left), and by centri- 

 fuging (one small and one large/ machine appear on 

 the left in Fig. 2), is installed, and the principal 

 operations involved in the later treatment of a filter- 

 press cake — for instance, squeezing in a hydraulic 

 press (Fig. 2) or in a screw press (Fig. 4, lying on 

 floor), drying in evacuated steam-ovens, and grinding 

 in an edge-runner mill (not shown) — are all provided for. 



A word should be said regarding the steps which 

 have been taken to solve the problem of ventilation. 

 General ventilation is provided by a 36-in. fan work- 



NO. 2698, VOL. 107] 



Fig. 5. — Vacuum and air-pressure services. 



ing in an aperture in the wall. In addition, how- 

 ever, a main draught trunk, operated by a separate 



