466 REPORT—1883. 
1. Those accompanied with no utilisation or recovery of the bye-products. 
2. Those utilising the bye-products merely as fuel, burning them, but recover- 
ing none. 
"3, Those recovering bye-products, and utilising as fuel the gaseous portion 
thereof. 
Representative forms of the Ist kind. (i.) The Meiler or Mound. (ii.) The 
Beehive oven. 
Representative forms of the 2nd kind. The Appolt and Coppée ovens. 
Representative forms of the 8rd lind. (A.) Admitting air, and so involving 
partial combustion. The Jameson oven. 
(B.) Closed ovens; and thus inyolying destructive distillation, Knab’s, Pauwell’s 
and Dubochet’s, Pernolet’s and Simon-Caryés’s ovens. 
In Jameson’s oven is a simple modification of the Beehive form. Jameson 
substitutes for the solid floor of the latter oven, one of perforated quarls, but quite 
recently finding difficulty in the stopping-up of the perforations, he uses tiles, 
placed on sleeper-walls, and somewhat apart, so as to allow spaces between them. 
From this floor and underneath it a pipe passes to the hydraulic main, and in this 
way all the ovens are connected with the hydraulic, and thus with the usual 
scrubbing and exhausting apparatus usual in gasworks. 
The coke obtained by Jameson’s process is good, in fact like that from the 
Beehive oven. As regards ammonia, Jameson states that he can obtain ammo- 
niacal liquor equal to a production of from 5 to 15 lbs. of sulphate of ammonia per 
ton of coke (equalling about 3 to 9 Ibs. per ton of coal). Truly there is a some- 
what uncertain sound given by these figures, betokening some want of definiteness, 
and that they cannot be derived from an average involving trials on a really large 
scale. 
The returns Jameson gives of tar yielded per ton of coal, viz. 6 to 15 galls. 
per ton of coke (equalling about 34 to 9 galls. per ton of coal) are also somewhat 
bewildering, and do not appear to have been derived as averages of extensive trials 
so much as from thé results of scattered experiments. However, this tar or tar-oil 
the author has carefully examined, and finds it to possess all the characteristics of 
tars produced at low temperatures, It has a specific gravity of 0-960. No benzol 
is present in this tar, but the statements which have been frequently made to the 
effect that no aromatic substances, only paraffins, are present, is not true. Small 
quantities of toluol and of xylol are certainly present in admixture with bodies of 
the marsh-gas series. The chief bulk of the Jameson tar, however, consists of oils 
boiling between 250° and 350°, and these oils suitably purified and refined the 
author has found to be of little value for burning-lamps, and but of secondary value 
as lubricants. ‘They are quite devoid of blueness or fluorescence. A considerable 
proportion of oil distils over above 350°, viz. from something like 400° to the point 
at which pitch remains in the retort, and from these oils paraftin scale does separate, 
though in unsatisfactory quantity. The paraffin wax obtained has a high melting 
point, viz. about 58° C.: the paraffin wax of the Scottish shale distillers melting 
at about 52° C. 
The crude phenols extracted in the usual way from the oils boiling between 
200° and 300° contain a series of phenols of increasing boiling points of a most 
peculiar kind, certain of them resembling the constituents of the creosote of wood- 
tar. Moreover, others of these phenols produce in combination with alkalis blue 
or violet and red-coloured compounds, decomposed by acids, with destruction of . 
the colours. These colours are of no stability or value. Not a trace of either 
naphthalene or of anthracene is present in Jameson’s tar. Amongst the closed 
ovens, the Simon-Caryés is the best form, for it yielded excellent metallurgical 
coke, only lacking the silvery glance of the Beehive product, but possessing even 
more density and solidity. 
The ammoniacal liquor obtained amounts to 27'7 gallons at from 6° to 7° 
Twaddell, and the tar, which the author has found to be almost identical in com- 
position with the best London coal tars, and having a specific gravity of 1:20, to 6:12 
gallons per ton of coal respectively. These are the average results from the coking 
of 7,000 tons of coal in the Simon-Carvés’s ovens at work at Messrs, Pease’s West 
