^{page 197 note 1} A.J.A. 1912, p. 235.

^{page 197 note 2} Zebn Bücher über Architektur, etc. Strassburg, 1912.

^{page 197 note 3} Vitruv. ii, 6, 1.

^{page 197 note 4} ii. p. 49: “mit scharfem vulkanischen Sande.”

^{page 198 note 1} ii, 4: “genera autem harenae fossiciae sunt haec, nigra, cana, rubra, carbunculus. ex his quae in manu confricata fecerit stridorem erit optima, quae autem terrosa fuerit non habebit asperitatem, item si in vestimentum candidum ea coniecta fuerit, postea excussa vel lota id non inquinarit neque ibi terra subsiderit, erit idonea.”

^{page 198 note 2} The meaning of this word will be discussed further on in this article.

^{page 199 note 1} cf. v, 12, 2: “eae autem structurae quae in aqua sunt futurae, videntur sic esse faciendae uti portetur pulvis a regionibus quae sunt a Cumis continuatae ad promuntorium Minervae, isque misceatur uti in mortario duo ad unum respondeant.”

^{page 199 note 2} Encycl. Britannica, s.v. Tuff, by J. S. Flett.

^{page 199 note 3} An excellent discussion of some of the above points occurs in the recent work of de Montauzan, C. Germain, entitled Les Aqueducs antiques de Lyon (Paris, 1909), pp. 263–273Google Scholar.

^{page 199 note 4} ii, 6: “est etiam genus pulveris quod efficit naturaliter res admirandas.”

^{page 200 note 1} Another instance in which Vitruvius has been wrongly accused of inaccuracy is given by Hoech [Berl. Phil. Wocbenschr. 1st Feb. 1913), where it is shown that the word bypaethral does not mean “exposed to the open sky,” but merely “open to the air,” as a colonnade.

^{page 200 note 2} e.g. i, 5, 8; v, 12, 2 (see above).

^{page 200 note 3} vii, II, I: “harena enim cum nitri flore conteritur adeo subtiliter ut efficiatur quemadmodum farina,” etc.

^{page 200 note 4} Q.N. 3, 20, 3. This passage refers to the construction of hydraulic cement from pozzolana, and the word pulvis is used. In another passage (Q.N. 2, 30) arena is loosely used in describing volcanic dust, but even in this passage it is also referred to as a powder (involutus est dies pulvere).

^{page 200 note 5} N.H. xvi, 202: “ibi namque demersa est Claudio principe cum tribus molibus turrium altitudine in ea exaedificatis obiter Puteolano pulvere advectisque.” Also in xxxv, 167: “non multum a pulvere Puteolano distat e Nilo harena tenuissima sui parte, non ad sustinenda maria fluctusque fragendos, sed ad debellanda corpora palestrae studiis.”

^{page 200 note 6} Silv. iv, 3, 52–3: “illi saxa ligant opusque texunt cocto pulvere sordidoque tofo.”

^{page 200 note 7} v, c. 245, f.

^{page 200 note 8} Die Baustile (2nd ed.), ii, 2, p. 193.

^{page 201 note 1} The Remains of Ancient Rome.

^{page 201 note 2} “In caementiciis autem structuris primum est de harena quaerendum ut ea sit idonea ad materiem miscendam neque habeat terrain commixtam.”

^{page 201 note 3} “Est etiam genus pulveris quod efficit naturaliter res admirandas. Nascitur in regionibus Baianis et in agris municipiorum quae sunt circa Vesuvium montem. quod commixtum cum cake et caemento non modo ceteris aedificiis praestat firmitatem, sed etiam moles cum struuntur in mari, sub aqua solidescunt.”

^{page 202 note 1} Daremberg and Saglio, s.v. arena.

^{page 202 note 1} Marucchi, Éléments d'arch. chrét: Notions générales, pp. 111–112.

^{page 202 note 3} It is possible, for example, that not enough stress has been laid on the facility and cheapness with which pozzolana could be brought to Rome from the bay of Naples by way of Ostia. Sea transport has always been cheaper than that by land, and was especially so in ancient times. Thus it may have been less expensive to bring pozzolana in this manner to Rome than to transport it for even a short distance from the neighbouring quarries.

^{page 202 note 4} ii, 4.

^{page 202 note 5} s.v. arena, by Guillaume.

^{page 202 note 6} op. cit. p. 73.

^{page 203 note 1} Vitruv. ii, p. 84.

^{page 203 note 2} s.v. carbunculus.

^{page 203 note 3} Lib. col. i, p. 227, 15: “aliis vero! ocis muros macerias scorofiones congerias carbunculos.” Also 243, 11: “in saltibus sunt scorofiones et carbunculus, id est scorofion molis petrarum constructi.”

^{page 203 note 4} de Re Rust. iii, II: “quis enim vel mediocris agricola nesciat etiam durissimum tophum, vel carbunculum, simulatque sunt confracti et in summo regesti, tempestatibus, geluve, nec minus aestivis putrescere caloribus ac resolvi; eosque pulcherrime radices vitium per aestatem refrigerare, succumque retinere? quae res alendo surculo sunt accommodatissimae.”

^{page 203 note 5} ii, 6: “itaque uti in Campania exusta terra cinis, sic in Etruria excocta materia efficitur carbunculus. utraque autem sunt egregia in structuris, sed alia in terrenis aedificiis alia etiam in maritimis molibus habent virtutem. est autem materiae potestas mollior quam tofus, solidior quam terra, qua penitus ab imo vehementia vaporis adusta, nonnullis locis procreatur id genus harenae quod dicitur carbunculus.”