[ToC]

 

LACHRYMA VITREA

Rebecca Ariel Porte

Brittle, glittering things we have loved & despaired of: mica, salt, Dutch tears, integrated circuits, a blue glass kerosene lamp, umber doublure in old books, dream sickles of shade, falciforms pared in the infamous steel-green grass, quips, jacks, cracks, flacons, figures, tacks, you, you, you (mostly you).

 

 

 

 

 

 

 

 


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Lachryma vitrea are a sort of old-fashioned toy, a bulb of glass with a long tail (rather like a tadpole or a single spermatozoon in shape). The bulb-end is impervious, even under great pressure, but when the tail is hit--even a gentle tap will do--the drop explodes to a dusty shimmer of nothing. Lachryma vitrea have gone by many names--glass tears, glass pears, Dutch tears, Prince Rupert's drops--& have charmed & puzzled scientists as often as idle children. In An Essay on the First Principles of Natural Philosophy (1762), William Jones writes "of a toy made in our glass houses, which the learned have treated of under the name of lachryma vitrea; the workmen call them glass-pears...commonly sold in London for the diversion of school boys; though they are attended with a phoenomenon, which hath excited the admiration of most of the philosophers in Europe. They are made of the ordinary green glass, by letting fall a large drop of it, when in fusion, into a vessel of cold water. If a piece of the neck be afterwards broken from the drop thus prepared, the whole body of it bursts asunder with an explosion, and is split into a thousand small fragments, which may be crumbled into dust without injury to the fingers" (157) . Much work remains to be done (scientifically & otherwise) on the topic of fracture mechanics, the study of the propagation of cracks. There is something, perhaps, particularly compelling in the fragility of seemingly invulnerable objects.