REMARKS UPON THE TEETH OR COGS OF WHEELS. 



189 



or material of starch, was only blackened 

 by it, yet strong difficulties are asserted 

 to oppose this opinion, the most material 

 of which is the indissoluble nature of the 

 particles of smut, which seemed to be lit- 

 tle affected by the power of boiling water, 

 spirit of salt, oil of vitriol, or aquafortis: 

 but a solution of soda appeared to exert 

 the greatest power on this mysterious 

 substance, which, though it did not dis- 

 solve the globules, yet seemed to render 

 many of them more white and pelucid, 

 and separated from a substance, the par- 

 ticles of which were too small to be dis- 

 tinguished by the magnifying power em- 

 ployed. 



If then the infectious nature of the 

 smutty powder be acknowledged, and if 

 the infecting substance consists of the 

 relics of any putrid matter, it is contend- 

 ed that there is the strongest reason to 

 believe that either lime, potash, soda, 

 spirit of salt, oil of vitrol, aquafortis, 

 arsenic, or corrosive sublimate, are ca- 

 pable of destroying or neutralizing this 

 substance, so far as to prevent any infec- 

 tion from taking place: and among these 

 ingredients lime is held to be the most 

 eligible, both on account of its cheapness, 

 and the little power it possesses of de- 

 stroying vegetation: many instances, 

 however, of its inefficacy may arise from 

 the mildness of its operation, and it may 

 be many hours before it can produce its 

 full effect. This writer is of opinion that 

 the failure of lime to destroy smut may 

 almost always be traced to an imperfect 

 application, for it has been the unvarying 

 complaint of many writers on husbandry, 

 that " seed is seldom steeped a sufficient 

 length of time." And though he consi- 

 ders lime the most efficacious of all re- 

 medies for smut, yet he thinks there is 

 no rational ground to expect a perfect 

 cure of smutty seed, unless it be steeped 

 in strong lime-water for at least 12 hours. 



Note. — The spirit of salt is mentioned 

 in the above experiments, but not a sim- 

 ple brine made with salt and water. It 

 is certainly worthy of experiment to 

 make trials of this substance at different 

 temperatures from that of the freezing 

 point, to that of boiling water, (32° to 

 212° Fahr.,) or to still greater extremes 

 each way. 



Unleached wood-ashes, and ley pro- 

 duced from this substance, of the same 

 range of temperatures is also worthy of 

 trial: this as well as the brine possesses 

 the advantage of cheapness, and can be 

 procured almost at any time and 

 in any place where they may be 

 required for this purpose. Iti mak- 

 ing trial of the brine or ley, per- 

 haps it would be well to extend the ex- 

 periments with these substances at dif- 

 ferent degrees of strength from the 

 weakest solution vp to the point of 

 saturation where it ceases to be a li- 

 quid. Jjgric. Mag., No. 27. 



For the Observer and Record. 

 REMARKS UPON THE TEETH OR COGS OF 

 WHEELS, SHOWING THE PROPER FORM 

 TO BE GIVEN TO THEIR ACTING SIDES 

 OR FACES. 



Wheels working in contact should al- 

 ways fulfil the following conditions, 

 namely: 



1. The relative velocity of the peri- 

 pheries should be uniform. 



2. There should be the least possible 

 rubbing or friction between the acting 

 sides or faces of the teeth. 



3. There should be the least possible 

 crowding asunder of the wheels. 



4. The shape of the teeth should be 

 such that those formed upon the exterior 

 convex surface (called spur-wheels) of 

 the smallest size, should work into or be- 

 tween those on any intermediate convex 

 surface from those of the same size up to 

 the largest, and also into or between 

 teeth placed in a straight line (called a 

 rack.) 



5. The same small spur-wheel should 

 (besides working between the teeth of 

 the aforesaid spur-wheels and rack, and 

 driving them, or heln^driven by them) 

 be capable of driving wheels with the 

 teeth formed on the interior surface or 

 concave part, and also be driven by them, 

 if required. 



In order that the reader may readily 

 understand the following description, I 

 will, in the first place give the definition, 

 of some of the terms used. The part of 

 the tooth which joins the wheel, I call 

 the base of the tooth: the opposite ex- 

 tremity, I call the end of the tooth. 



