xviii. Proceedings. [Febriuiry 21st, 1922. 



which the air is pumped through it. (2) Another coil over the 

 loose paper is converted into a magnet by the same current, 

 when it attracts an armature which lies below the paper ; these 

 fix the paper between them. (3) The coil is then pushed back- 

 wards for half an inch, carrying the paper ribbon with it ; (4) it 

 pushes round a disc, which rolls up the paper with the impres- 

 sions, on to a cylinder. (5) It breaks a short circuit which puts 

 two glow lamps into the circuit to prevent the heavy sparking 

 when the contact is broken by the clockwork. When this takes 

 place the small coil ceases to be magnetic, its armature falls, 

 and the coil and armature are carried backwards by a spiral 

 spring which pulls out the core of the magnet from the coil 

 read}^ for the next series of evolutions. 



These dail}" records show that the air of Manchester is never 

 absolutel}^ free from smoke. It is cleanest between midnight 

 and five or six o'clock in the morning, and foulest between nine 

 and ten o'clock in the morning. There are on the average 

 increased variations between one and two o'clock, between four 

 and five o'clock, and between six and seven o'clock in the 

 afternoon ; then it gradually becomes less smoky up till mid- 

 night. It was shown that the smoke during the Coal Stoppage 

 last summer was about one-tenth of what it became afterwards. 



2. *' Apparatus for Estimating- the Chemical Impurities 

 in the Air by Washing a Large Volume with a 

 Small Quantity of Water." 



This apparatus was designed after the Stromeyer appliance 

 for washing small quantities of gas which by suction passes the 

 gas in bubbles, together with the liquid, along a series of spirals 

 in a glass tube, the liquid falling back into a small glass 

 reservoir, to be used again and again as the gas is sucked away. 

 The author used a 3 ft. tube, ij in. diameter, filled with small, 

 pure snow-white silica pebbles. To the top of this tube was 

 fixed air-tight, a J in. tube, 27 in. long, which w^as bent over 

 dow^nwards and fixed air-tight into the top of a vertical tube 

 8 in. long by ij in. diameter. Into the top of this tube, but just 

 penetrating the cover, was filled another tube attached to a 

 mechanical pump worked by a djaiamo, and from the bottom 

 of this wide tube was fixed a narrow tube going to the bottom 

 of the wade tube containing the pebbles. Into the bottom of 

 the same cover w'as fixed the air tube, wdiich was bent sharply 

 round, and rose above the height of the tube containing the 

 pebbles. Through this tube the air passed after being filtered 

 through paper ; it bubbled amongst the pebbles to the top, then 

 washed up the narrow tube with some of the water to the top 



