TRANSACTIONS OF THE SECTIONS. 141 



(hi an Hydraulic Coal-cutting Machine. By W. E. CifiRETT. 

 The machine, by means of a series of ingenious mechanical aiTangements, is 

 capable of being most readily adjusted and moved to suit the various conditions 

 under which it is required to be used in the pit ; and these could only be made 

 intelligible by means of elaborate diagi-ams or inspection of the machine itself or 

 the model. The principle on which the machine works is that of the pianino- and 

 slotting machine, the cutters acting by direct continuous pressm-e derived from a 

 column of water, and not by blows. The machine has been in successful operation 

 for more than two years. 



On the Counterbalancing of Winding Engines for Coal Mines, 

 By John Daglish. 



On Steam-BoUer Explosions, with Suggestions for their Investigation. 



By H. DiRCES. 



Description of the Means employed for removing and replacing in a new por- 

 tion the Iron Columns of a Fireproof Cotton Mill. By "William Faib- 

 BAiRN, LL.D., F.R.S. 



The improvements that have been effected in the machinery for spinning cotton 

 have given rise to new conditions, new buildings, and new appliances to meet the 

 numerous changes that have taken place. The machinery for carding, roving and 

 spinning has been renewed three different times within a period of less than sixty 

 years, the old machines having been three times removed to give place to others 

 of a more improved construction. The old narrow buildings of former days have 

 consequently proved unequal to present wants, and it has been necessary either to 

 alter the old mills to suit the new machinery, or to build new ones. The latter 

 plan was occasionally preferred ; but more frequently the spinning-rooms of the old 

 mills were converted to the new mules, which from their increased number of 

 spindles had to be fixed in the longitudinal direction, instead of transversely as 

 formerly. 



Immediately after the invention of the mule by Crompton, or about the com- 

 mencement of the present century, a cotton-mill 45 feet in width was considered 

 of proper dimensions for mules of 350 to 400 spindles. Two of these mules 

 were looked upon for many years as the correct number for one man to work • and 

 this might have been continued for a longer period, but for the invention of the 

 self-acting mule by the late !Mr. Roberts and otners, which gave a new impetus to 

 the spinning process ; and in place of 400 spindles, as formerly, the mules of the 

 present day contain from 800 to 1000 spindles. This increase in the length of the 

 mule requires a corresponding increase of width in the mill ; and hence arose the 

 tower-like form of modern cotton factories, varying from 90 to 100, and in some- 

 cases from 110 to 120 feet wide. 



In the construction of modern miUs no difficulty exists, as they are built to suit 

 the machinery ; whereas in adapting the old narrow buildings to "the new mules it 

 was necessary to break up the old mules, and place the new ones in the opposite 

 or longitudinal direction of the mill. In mills with wooden floors, this was easUy 

 accomplished by removing one row of columns to admit a pair of mules in the 

 middle ; but in fireproof buildings, constructed with iron beams and brick arches 

 the greatest possible care was necessary to be obsen'ed in effecting the desired 

 alteration, as illustrated in the case forming the subject of the present paper 

 where 90 to 100 tons of arches and machinery had to be supported on two columns 

 or one bay, in a building eight stories high, the mill being kept working during 

 the whole time the alterations were going on. 



The objection to this operation on the part of the proprietors, Messrs. M'Con- 

 nel and Co., was, that the columns could not be removed without cutting them 

 which might incur the danger of the floors above being " brought down by the 

 run." Each column had, in fact, to be cut in two, taken entirely out and new 

 ones substituted at the required distances apart. As the particulars may be useful 



