Harvey on the Deposition of Detv. 41 



cepting that of temperature, remained the same. Soon after the 

 last observation, the upper sky again became clear; when the form- 

 ation of dew was actively resumed, and an additional quantity, 

 amounting to ten grains, deposited by six the next morning. 



On the 16th of May, the sun rose about a quarter after four; 

 and from that time to six, dew was deposited on wool and swan- 

 down placed on grass, and at the elevations of 5, 18, and 32 in- 

 ches above the ground. Nor was the quantity, in some cases, in- 

 considerable, it varying from one to three grains. At the last ob- 

 servation, the sun had attained an elevation of 13 degrees ; and 

 for half an hour previous to it, had thrown its direct rays on the 

 scene of the experiments. Dew, therefore, is deposited after 



sunrise. 



Plymouth, July 25th, 1823. 



Art . V. On Animals preserved in Amber, with Remarks on 

 the Nature and Origin of that Substance. By J. Mac 

 Culloch, M.D..F.R.S. 



The value which has long been attached to the specimens of 

 amber which contain insects, has introduced into the cabinets of 

 collectors many imaginary examples of this occurrence, which a 

 more careful examination would have proved to be fallacious. 

 For the sake of those who may be inclined to purchase such spe- 

 cimens, or to re-examine their own acquisitions of this nature, it 

 may be useful, not only to suggest the frequent deceptions to 

 which they are exposed by not attending to the real characters of 

 the including material, but to point out an easy method of dis- 

 tinguishing the true from the false. It is the more necessary to 

 ■do this, as the test which the Abbe Haiiy has given, in his work, 

 for this purpose, is neither satisfactory nor of easy application. 



The existence of an insect in amber, is an unquestionable proof 

 of the vegetable origin of this remarkable substance, and is, there- 

 fore, in a mineralogical view, an important fact ; but to find such an 

 animal in the exudation of a living vegetable, is scarcely a subject 



