554 



NA TURE 



[October 7, 1897 



for condensed water. The outlet of the sink connects through 

 a wooden pipe with a V-shaped wooden trough lined with 

 lead and pitched, which, after picking up from all the sinks 

 in the table, discharges into a galvanised iron funnel, also 

 coated with pitch ; a continuing pipe conveys the dirty water 

 into drains outside the building. 



Fischer's brass filter pumps with vacuum gauge attached are 

 fixed to the tables, and the water passing through them is 

 conveyed by a system of pipes into the clean water return-main, 

 as is also the water drawn from the side tubes of the water 

 standard. 



Sets of shelves for reagent bottles, consisting of three plates 

 of glass supported on gun-metal brackets, are fixed on the walls 

 at the back or ends of the tables. 



In the main laboratory there are eight tables arranged in 

 two rows, four tables being on each side of a wide central 

 gangway, with a clear space of five feet between each table. 



The tops are twelve feet long by five wide, and each table 

 affords working space for four operators : a white ware sink 

 (20 X 9 X 4I inches) is placed at each end of the table, and 

 the standards delivering water into the sinks serve as pillars 

 carrying a shelf nine feet long by one foot wide, which runs 

 down the centre of the table between the two sinks at a height 

 of one foot above the table top. Along the under surface the 

 wires for the electric light are carried, and a plug is fixed on 

 each side for motor attachments. 



The two water standards are connected by a water pipe 

 running underneath the shelf, and from this pipe four branches 

 are taken on each side for supplying water to the still condensers. 

 This water comes from the cooled water cistern, and after doing 

 its work is passed through nozzles fixed on the table top into a 

 pipe running underneath along the middle of the table, which 

 finally connects with the return clean water main. 



The tables stand on a plinth with recessed toe space, the top 

 overhangs three inches all round ; the cupboards and drawers 

 are similar to those already described. Between the backs of 

 the opposite cupboards is a space similar to that between the, 

 backs of the cupboards and the walls in thje other laboratories, 

 and this space is utilised for holding the water pipes and drain- 

 ing trough. The gas supply pipes are carried along the fronts 

 of the tables in all the laboratories immediately below the over- 

 hanging portion, with off-takes leading to nozzles fixed on the 

 top of the tables at the back. These off-takes are copper tubes 

 which pass through the framing of the drawers, the contro. 

 cocks being in front of the table. 



All the principal laboratories are provided with evaporation 

 closets, steam sand trays, steam drying ovens, distilled water 

 apparatus, and cabinets for holding and using standard volu- 

 metric solutions. 



The evaporation closets are very similar in character to those 

 already in use at the Yorkshire College and elsewhere. They 

 consist of a slate slab placed in front of a flue mouthpiece ; a 

 copper conical vessel is bolted to the under surface of the slab, 

 which is perforated with a large bevelled hole in which is fitted 

 a white stoneware collar. This collar, together with the copper 

 portion, forms a hollow inverted cone, passing through the slate 

 with a base 12 inches in diameter, on which is placed a thin 

 steel plate coated on both sides with a rubber composition called 

 " woodite," and perforated with holes of various sizes for hold- 

 ing basins, capsules and similar vessels. The upper portion is 

 enclosed in a glass case resting on the slate slab, the front being 

 a glass door sliding up and down by means of a counterbalancing 

 weight working over pulleys. The roof is a plate of glass 

 sloping down from front to back, with its back edge placed just 

 above the top of the mouthpiece. A valve placed underneath 

 the slab admits steam into the copper under portion of the 

 cone, and any accumulation of condensed water flows away by a 

 pipe fixed at a level slightly lower than the steam inlet. This 

 pipe connects with a cubical cistern of brass with plate-glass 

 front, arranged to act as a constant level apparatus in the 

 event of steam not being available, in which case the bath is 

 heated by a safety Bunsen burner placed immediately below the 

 inverted copper apex. 



The drying ovens, steam sand trays, and distilled water 

 apparatus are all constructed as constituent parts of one 

 appliance, through which steam from a single inlet circulates. 

 The sand tray is a shallow copper vessel 30 x 12 inches ; below 

 it is a copper jacket lined with tin, through which the steam 

 passes. It is well insulated and lagged round the sides and 

 bottom, and forms the top of an enclosed oak cabinet fitted 



NO. 1458, VOL. 56] 



with wooden rails for holding dusters and towels, which are 

 dried by the waste heat. Reduced steam first passes through 

 a steam trap which automatically discharges the accumulation 

 of condensed water, the outlet from the sand tray being 

 so arranged that there is always available a supply of 

 hot distilled water which can be drawn off as required 

 through a Kelvin bib cock placed immediately over the cabinet 

 doors. 



From the sand tray the steam passes into the drying oven, 

 which is fixed on the wall immediately above the sand tray. 

 This oven is a stout copper-jacketed vessel insulated and lagged, 

 the doors being fitied with plate-glass panels. Air for ventilation 

 is admitted at the bottom and passes through a copper coil in 

 the steam jacket, so that on entering the bath it is heated up to 

 the temperature of the steam, and escapes through a similar 

 opening at the top. 



From the top of the oven a copper pipe leads the excess 

 steam into the distilled water apparatus. This is an iron cylinder 

 supported on brackets, and contains a block-tin worm, the upper 

 end of which is connected with the pipe from the oven. The 

 lower end delivers distilled water into a large earthenware jar 

 standing on a wooden pedestal. A glass cock passes through a 

 tubulure at the bottom of the jar in front, and through a similar 

 tubulure on the right-hand side of the jar is fitted a glass water 

 gauge, which also serves as an automatic overflow by being 

 bent over into a funnel placed behind the jar ; this funnel also 

 receives water from the cylinder containing the block-tin worm, 

 and by suitable connections delivers the water into the tank 

 under the basement. 



The appliance for holding the standard solutions is a shallow 

 cabinet of Riga wainscot fixed against the walls, with polished 

 plate-glass top and four doors ; the panels of the upper doors 

 are of glass, and the plinth is protected by a countersunk band 

 of brass. The bottles containing the standard solutions stand 

 on a shelf immediately behind the glass doors, and are fitted 

 with two-holed rubber stoppers, through which pass a soda-lime 

 guard tube, and a glass tube dipping down to the bottom of the 

 bottle. This glass tube is connected, by india-rubber tubing 

 which passes through a bevelled hole in the plate-glass top, with 

 the stoppered side tube of a burette. Each burette is held in 

 position by a pair of small clips fixed on two parallel brass bars, 

 the bars being supported between a pair of brackets fixed to the 

 ends of the cabinet on the plate-glass top. These clips ensure a 

 perfectly rigid perpendicular position, and at the same time 

 allow the burette to be easily raised or lowered. The burettes 

 are filled with the standard solutions by suction through the 

 top end of the burette, which is fitted with guard- tube con- 

 tinued by a depending piece of india-rubber to a glass mouth- 

 piece. 



The tobacco laboratory is provided also with special drying 

 ovens and furnaces for incinerating vegetable substances. The 

 drying ovens, three in number, are placed on the wall one above 

 the other, and steam for heating them is generated in a special 

 boiler standing close by, the condensed water flows back into 

 the boiler, which is also connected with an independent water 

 supply, having a valve and ball-cock for keeping constant 

 level. 



The carbonising and muffle furnaces are arranged in two 

 chambers of white glazed bricks, supported on arches which 

 spring from a large York flagstone ; apertures in the roof 

 communicating with a flue for carrying off the fumes and 

 heated air. For carbonising the tobacco a special furnace has 

 been designed. From the gas main in front of the chamber 

 five branch pipes connect with long rectangular tubes. On 

 each tube are .screwed eight brass boxes, with a lever gas-cock 

 between each box and the tube. Near each corner of the box 

 a small Bunsen burner is fixed, and by this means a small flame 

 plays uniformly over the under surface of the platinum dishes, 

 which are supported on a light wrought-iron nickel-plated grid. 

 The furnace is capable of holding forty dishes at one time. The 

 front of the chamber, in which the furnace stands, is closed by a 

 counterpoised glass door sliding up and down. 



The incineration of the samples is completed in three muffle 

 furnaces, of special design, heated by gas. 



The whole of the work in connection with the building and 

 fittings has been carried out under the immediate supervision of 

 H.M. Office of Works, from designs supplied by Dr. Thorpe, 

 and the manner in which the work has been executed reflects 

 the h ighest credit on that department. 



J. Woodward. 



