534 I'HILOSOPHICAI- TRANSACTIONS, [aNN0 174I. 



dimensions of the several parts, who, the alveus being quite black with smoke, 

 returned like a chimney-sweeper, but could not take the exact measures of the 

 fornax and praefurnium, on account of rubbish he found in them; therefore 

 Mr. Sympson, being desirous to inform himself thoroughly of all the parts of 

 this curious piece of antiquity, with the leave, and at the expence, of the pro- 

 prietor, caused another hole to be sunk l6 feet deep, and by driving a level op, 

 fig. 1 and 2, he broke into the middle of the fornax; and, having cleared it of 

 rubbish, found its dimensions as above, and that the bottom of the narrowest 

 part between f and g, was raised 18 inches higher than the bottom of the part 

 between e and f. 



The praefurnium was covered over at top with a large flat stone. The fornax, 

 and the two square pillars in the alveus fronting the opening of the fornax, 

 were greatly impaired by the fire, which must have been very violent; some 

 small fragments of wood-coal were thrown out among the rubbish in the bottom 

 of the fornax; whence probably it was heated with wood. 



At the conclusion of the account, Mr. Sympson gives the following remark 

 on a passage in the second letter from Mr. Baxter to Dr. Harwood, concerning 

 the hypocausta of the ancients, printed in these Transactions, N° 306. " Mr. 

 Baxter says, the hypocausis was called alveus and fornax; but, with due defer- 

 ence to that learned gentleman, says Mr. Sympson, I humbly apprehend them 

 to have been distinct parts of the whole, which was called hypocausis: the 

 ground of this conjecture is; in the first place, it would hardly be possible to 

 make a fire in that part of this hypocaust, which he calls the alveus; much less 

 to come at it to manage it, being so low, and so crouded with pillars, as to 

 admit only a slender person to crawl among them, and that not without diffi- 

 culty. In the next place, the floor does not seem designed for it, nor are there 

 any appearances of ashes on it ; and further, that the fornax was where he has 

 placed it in this, appears not only from the structure of that part, but from the 

 bricks being much burnt, and pieces of wood-coal being found in it; whereas 

 in the alveus, the bricks are only black with the steam and smoke being drawn 

 through it by the tubuli." He might have added, that only those pillars in the 

 alveus, which faced the mouth of the fornax, had suffered much by the fire, 

 the others not. 



That hypocaust, described in N° 306, abovementioned, must have been a 

 much hotter room than this; for, instead of the flues being carried under an- 

 other room, the walls of the sweating-room itself were hollow or double, and a 

 great number of flues carried up between them all round the room. A curious 

 model of this was to be seen in the museum of the Royal Society. 



This hypocaust may serve as a model for malt-kilns, or for drying hops, &c. 



