190 Miseellanies. 



called, but of all substances, natural or artificial, which it has pleased the 

 fancy of mankind to esteem as objects of personal ornament, and which 

 are usually known by the name of precious stones. He gives a minute 

 account of the preparation of pastes, or imitations of real gems, of the 

 method of cutting and polishing all gems, and of the forms most suitable 

 to enhance their natural beauty. The history of the diamond, the prince 

 of gems, and by many esteemed a better standard of value than silver or 

 gold, is drawn with much care, and is particularly interesting, viewed 

 either as a scientific or practical account. 



This book, taken in connection with that of Prof N. F. Moore, of Co- 

 lumbia College, viz. " Ancient Mineralogy, or an Inquiry concerning the 

 Mineral substances mentioned by the Ancients, &c." and noticed in this 

 Journal, (Vol. 28, p. 188,) affords a very complete view of the history 

 and antiquity of those gems and minerals which were known in the early 

 periods of society. 



Dr. F. has endeavored to Americanize his book, by giving an ac- 

 count of all the principal American localities of precious stones, and 

 ornamental and architectural materials ; with the hope of calling more 

 attention to our internal resources of this nature. At the conclusion of 

 the present treatise, it is announced that Dr. F. is to publish a " Miner-, 

 ALOGicAL Text Book, /or the use of schools, seminaries, and private stu- 

 dents. This latter work is intended not to be strictly philosophical, as it is 

 a plain text book for the younger student, who wishes to be informed of 

 the elementary principles, and how to collect, and to classify the minerals 

 coming under his observation." 



15. Extreme heat at Cumberland, Md., communicated hy the Editor's 

 request. To Prof. Silliman — Dear Sir: In the afternoon of Saturday, 

 the 28th of July, the thermometer in the piazza of Black's Hotel, in Cum- 

 berland, Md.,* about two o'clock, was at 102° of Fahr. ; it gradually rose 

 to 104°; from about 3 to 4 o'clock it fluctuated from 102° to 106°, — and 

 at about 4 o'clock it rose to 107°, and then to 108^, where it remained 

 at 5 o'clock. One of the gentlemen then removed it from its position 

 against one of the pillars of the piazza in the shade, to one in the direct 

 rays of the sun, — it almost immediately rose to 120°, the highest gradu- 

 ation of the tube, filled it entirely, and the ball was soon after burst. At 

 Hancock, about 30 miles below, on the Potomac, at the same hour, the 

 thermometer varied from 107° to 109°. You are yourself familiar with 

 the position at Black's ; it looks, I think, nearly north. 



With great respect, your friend and servant, 



B. B. HOAVELL. 



' New York, Aug. 4, 1838. 



* Lat. 38" 58' N. Long. 77° 33' W. 



