TRANSACTIONS OF THE SECTIONS. 187 
of suitable dimensions, and placed between the cylinder and the crank as previously 
described, and for this purpose a double-acting pump with double trunk may, by 
increasing the length of the piston-rod and the connecting-rod, be employed. 
It will be seen from the foregoing description, that by the plan adopted by 
Messrs. Jackson and Watkins of placing the pump between the cylinder and the 
crank in direct-acting steam-engines, the usual guide bars and blocks are dispensed 
with; and that in working the air-pump in direct-acting condensing-engines 
according to this plan, the necessity no longer exists for the employment of sepa- 
rate and independent levers, beams, connecting-rods, &c. 
A novel Method of covering Boilers, Pipes, and Cylinders of Steam Engines for 
preventing the Radiation of Heat, the mvention of Mr. James Spence, of 
HM. Dockyard, Portsmouth. By W. Smiru, CLE. 
In the non-conducting compositions which Mr. Spence proposes to employ, argil- 
laceous earth is ground or beat up and mixed with water, so as to form a paste, 
with which is compounded oil-cake, fish- or train-oil, cow-hair, carbonaceous mat- 
ter, and the other materials afterwards mentioned, for giving consistency, character, 
or colour, according to the purpose for which the composition is required. The 
hair is well opened and beaten in or incorporated, and the whole mass is thoroughly 
mixed until it has obtained the requisite degree of density or consistency. 
For coating steam-boilers and such like vessels subject to great heat, and for 
other similar purposes, argillaceous earth (say, one thousand pounds in weight) is 
ound or beat up and mixed with water so as to form a paste. To this is added 
about twenty-four pounds of oil-cake, about three gallons of fish- or train-oil, and 
to this mixture is introduced about twenty-four pou of cow-hair, twenty-four 
pounds of soot, and three pounds of bone-dust or bone-ash. These are thoroughly 
combined together, and form a plaster or composition capable of being applied in 
the manner of plastering walls and other surfaces. 
For coating steam-pipes, steam-engine cylinders, and other such bodies and sur- 
faces, argillaceous earth (in weight, say, one thousand pounds) is taken and prepared 
as before; to this is added about thirty pounds of oil-cake, two gallons of fish-oil, 
about thirty-six pounds of cow-hair, fourteen pounds of soot, eighteen pounds of 
bone-dust, and fourteen pounds of ground carbonaceous matter; these are well in- 
corporated in a finely divided condition, as before stated. For purposes where a 
finer quality of coating is required, there may be less oil, less cow-hair and dry 
matter introduced in proportion to the weight of clay. 
For a finishing coat to the previously described compositions, the following sub- 
stances may be used :—To each one thousand pounds of argillaceous earth about 
one and a half or two gallons of fish-oil, about thirty-two pounds of oil-cake, thirty- 
two pounds of cow-hair, about half a gallon of linseed oil, twenty-four pounds of 
ground charcoal, and about eight pounds of glue; to these may be added about 
pe pounds of paint or colouring matter, of any colour or tint that may be pre- 
erred. 
Steam-boilers may be coated whilst in use ; and the composition may be applied 
by hand or trowel to a depth of three-quarters of an inch or so, and scored or grained 
across and allowed to dry, and then a second or any additional number of coatings 
may be added. 
or coating circular pipes or such like surfaces, a layer of hay or straw bands, 
‘saturated in the composition, may be lapped or coiled around the pipe or vessel, 
the composition plastered on, and the coatings or layers added at intervals. Wood 
laths may be introduced ; and any of the well-known means of bonding or binding 
may be employed, according to the form of the body to which the composition is 
to be applied, and according to the nature of the action to which the material is to 
be subjected. 
This process is intended to be used instead of employing felt and wood lagging 
with sheet-lead covering or other additions, as a covering for steam-boilers, cylin- 
ders, pipes, and such like, and other vessels and bodies, for prevention of the radia- 
tion of heat, as also for protecting pipes and other vessels containing fluids or liquids 
against the external action of extreme cold, and generally for coating vessels or 
