30 On the Drawing of Figures of Crystals. 
learned something of its fickleness, which appears to have produced 
some effect upon bis mind in souring it against human nature. In 
1802, he married the widow of the celebrated Lavoisier, but the 
union proved unhappy and they soon separated. After this event the 
most of his time was spent in retirement, till his death which occur- 
red August 21st, 1814. 
Count Rumford left an only daughter, who was born, not as Cu- 
vier affirms, at Concord, Mass., shortly after the battle of Lexing- — 
ton, from which her father had retired with the British troops to 
Boston, but at Concord, New Hampshire, Oct. 10th, 1774. She is © 
still living, and possesses the title of Countess of Rumford, and a 
jiberal pension. Much of her life has been spent in Europe, but she 
‘ came to this country the last season on‘a visit to her friends, and I 
believe is now with them. 
| 
Art. Itl—On the Drawing of Figures of 3 Crystals ; by James D. | 
Dana, A.M.,, Assistant in the department of Chemistry, eet? 
and Mineralogy 3 in Yale College. 
1. Tue modern and improved methods of projecting the crys- 
talline solids, have not, hitherto, been explained in any American 
publication ; it is therefore presumed that the following exposition of 
this subject will not be unacceptable to the scientific public. The 
“Introduction to Crystallography” of H. J. Brooke,* is the only 
work in our language, which treats of crystallographic projection; 
and this work though valuable at the time of its publication, and 
highly reputable to its accomplished author, is necessarily behind a 
science, which, since its publication, has been so rapid in its advan- 
ces. The principles embraced in the following pages, have been 
mostly drawn from the very complete and philosophical German 
treatise on crystallography by C. F. Naumann.+ 
2. The importance of accuracy in the delineations of crystals, is 
obvious. The edges of a crystal, as exhibited in a correct figure; 
constitute a language readily interpreted by the crystallographer- 
He reads, in them, the relations of each plane to the axes of the soli 
and with the preliminary knowledge of a few interfacial angles, (fre- 
A familiar Introduction to Crystall h H 
dio Lae 1923. rystallography, by Henry James Brooke, 508 pp- 
+ Lehrbuch der reinen und angewandten — aione wie Cul 
Siiedetich Seana Two vols. 8vo. Lei — lographie, 
