328 k:ansas city review of science. 



use an atomizer to settle the dust in the room, before his patient, who had a 

 bronchial disease, could find any rest or relief. In the minds of those who are 

 best informed on this subject this single objection would be sufficient to exclude 

 the limestone as a dressing for our streets. 



The limestone dressing is also objectionable in its injurious effects upon the 

 eye. The white glittering light reflected in a bright sun from the freshly broken 

 limestone is very trying to the eyes. Persons whose eyes are not very strong 

 cannot endure it, and turn away for relief from the glittering light. A surgeon 

 informs me that during the late war while in camp on the white sands of Florida 

 he blackened the tents of the soldiers and thus emptied his hospital of patients 

 having sore eyes, while the hospitals of those regiments whose tents were white- 

 washed were full of patients from sore eyes. The census of 1870 reported over 

 20,000 blind persons in the United States. If we count the pur blind, and those 

 who cannot see to read, this number would probably be more than doubled. The 

 estimate at the present time is placed as high as 50,000. Certainly no intelligent 

 people would multiply the causes of blindness. They would not spread their 

 streets from year to year with a substance whose optical effects are recognized by 

 the best authorities as highly injurious. 



It only remains to speak of the supply and cost of the Burlington gravel. 

 Captain Trowbridge has kindly furnished me some estmiates on this subject, pub- 

 lished with this paper, which I think can be reduced considerably. As the 

 foundation of stone will be the same with the gravel and broken limestone dress- 

 ing, we can drop it out of the estimate. The cleanly washed gravel from Shell 

 Island can be purchased, I am informed, at fifty cents a royalty by the carload. 

 But the stratum of gravel underlies the whole country, and west of Burlington in 

 many places it lies on the very surface, sometimes nearly four feet in thickness, 

 and can be obtained in unlimited quantities. The beds only need to be develop- 

 ed, and can never be exhausted. Gravel also exists in large quantities in the 

 Marias des Cygnes. The railroad now offers to bring the gravel from Burlington 

 to Kansas City for $15.00 a carload, and it is thought it can be brought in large 

 quantities at $10.00 a carload. Now if it will last ten times as long as the lime- 

 stone dressing, and judging from the Burlington macadam, it would with proper 

 repairs last a generation, we can easily see in the long run how much cheaper it 

 would be than the limestone. And the fact that the limestone is now broken 

 without expense to the city does not avail as the same force can be employed in 

 putting down the stone foundation, and thus free labor from the work-house made 

 of some profit to the city. 



I have submitted packages of the Burlington gravel to various experts, and 

 herewith publish their opinions : 



Prof. C. F. Chandler, chemist of the School of Mines, of Columbia College, 

 New York, writes: "In reply to your letter I would say that the sample of 

 gravel you sent me seems to be admirably adapted for macadamizing." 



