642 PHILOSOPHICAL TRANSACTIONS. [aNNO IJOQ. 



And after some such manner I take it to be with a human foetus ; that it is in 

 some disorder, and uneasy in the womb, and therefore cries, as well in as out 

 of it. 



Observations on the Edge of Razors, &c. By Mr. Lewenhoeck, F. R. S. 



N° 324, p. 493. 



When I view my razor, set in the best manner, through my microscope, I 

 am amazed at the great number of gaps and notches in the edge of it, and 

 wonder how one can shave so softly with it. As to the razor's becoming blunt 

 in cold weather, I can conceive no other reason for it, but that the materia 

 subtilis, or exceedingly fine matter, which is in all metals, and which we may 

 compare to fire, is by the cold driven out of the edge of the razor ; by which 

 means the steel becomes so stubborn or hard, that in a fine razor it makes 

 notches, and is blunted by the hair. I have also experienced, that after having 

 shaved the beard with a fine razor, and attempting to cut some of the little 

 hairs in the eye-brows, which were harder than those of the chin, though they 

 were a little softened with water, they made several notches in the razor. I 

 asked a certain skilful barber, what difference he found in his razors in very 

 cold or hot weather ; who informed me, that when it was very cold, he always 

 dipped his razors in warm water, which made them cut much better. 



M. Leuwenhoeck describes how he incorporates his leather strap with grease 

 and tripoly, or with emery powder, both of which have a good effect in preserv- 

 ing the edge of his razors. 



BND OF VOLUME TWENTY-SIXTH OP THE ORIGINAL. 



On the Usefulness of the Silk of Spiders. By M. Bon, P. R, S. of Montpelier. 



N° 325, p. 2. Fol. XXFII. 



Spiders make a silk as beautiful, strong, and glossy, as common silk: the 

 prejudice entertained against so common and despicable an insect, is the reason 

 that the public has been hitherto ignorant of its usefulness. Even common 

 silk, as considerable as it is, was long unknown, and was neglected after its 

 discovery. It was in the island of Coos, that Pamphila, daughter of Platis, 

 first discovered the manner of working it. This discovery became soon after 

 known to the Romans, who brought their silk from the country of the Seres, 

 a people of Scythia in Asia, near the mountain Imaus, where silk-worms na- 



