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Miscellaneous Intelligence. 



some method usually resorted to. Some few precautions must, of course, 

 be attended to. The vessel must stand firmly. If at first the water 

 will not flow, or flows fitfully, the obstruction will be removed by blow- 

 ing a little in the spout. 



An investigation of some interest, growing out of this matter, may 

 properly be noticed. Where we are operating on substances of low spe- 

 cific gravity, say wood or stone, a drop or two of water, or the size of 

 the drop, in tapering off the divisor, is of no consequence. But it is 

 otherwise in the case of a gold coin, for example : — in a double eagle, 

 the difference of one drop of water (ordinarily about a half-grain) in 

 the divisor, would affect the result to the extent of 0*3, which, carried 

 into the fineness, would make a difference of 15 or 20 thousandths; and 

 in the case of a half-eagle, the uncertainty of result would be propor- 

 tionally increased. The question then arose, what fluid, or what modi- 

 fication of water, will afford us a smaller drop ? for, as was just observed, 

 a half-grain is, on the average, the smallest of clean water that will de- 

 tach itself by its own weight. Very much depends, of course, upon the 

 size of the aperture, in the measure of drops of fluid ; one drop of water 

 from a large beak weighed 1^- grains. In the Dispensatory of Drs. 

 Wood and Bache, there is a table of the experimental results of Mr. 

 Durand, showing the number of drops of different liquids equivalent to 

 a fluidrachm (page 1405). The differences are very remarkable ; dis- 

 tilled water, for instance, being set down at 45 drops, and pure alcohol 

 at 138 drops. And in our own experiments, the drop of alcohol was 

 about one-third the weight of the drop of water, from the same pipette. 

 This seemed to point to alcohol as a substitute ; but there were obvious 

 objections, and a much better vehicle was found in soapy water. 



The best white soap, sold at the shops, is of the same specific gravity 

 as water, and its mixture with water makes no change, in that respect. 

 When the mixture is as strong as children use for blowing bubbles (we 

 cannot conveniently give this measure in figures), the cohesion or tenac- 

 ity of the water is so much weakened that the drop is reduced to one- 

 tenth of a grain. No other fluid makes so small a drop as this. And 

 there is the further advantage, that soapy water, though excellent for 

 making bubbles, is less liable to retain them below the surface than pure 

 water. So small a drop, of course, makes the experiment more tedious, 

 and, by using less soap, the size of the drop will be, in many cases, ad- 

 vantageously increased. ***** 



3. Discovery of Palceozoic Fossils in Eastern Massachusetts ; by Prof. 

 W. B. Rogers, (from a letter to J. D. Dana, dated Boston, August 

 13, 1856.)* — You will, I am sure, be surprised as well as pleased by the 

 news I am about to tell you. You are aware that the altered slates and 

 grits which show themselves interruptedly throughout a good part of 

 Eastern Massachusetts, have with the exception of the coal measures on 

 the confines of this State and Rhode Island, failed hitherto to furnish 

 geologists with any fossil evidences of a Palaeozoic age, although from 

 aspect and position they have been conjecturally classed with the system 

 of rocks belonging to this period. Indeed the highly altered condition 

 of these beds generally, traceable no doubt to the great masses of syenite 

 and other igneous materials by which they are traversed or enclosed, 



* This important paper was received too late for insertion under Geology. 



