784 



The Weekly Florists^ Review* 



January 31, 1907. 



the bars sixteen inches apart. A few of 

 the more daring growers liave risked 

 building their houses with the bars 

 twenty-four inches apart and using this 

 same size glass. In our own experience, 

 a number of customers have put the glass 

 in this way. In only one case do we 

 know of any trouble having occurred. 

 Such great advantages in economy of 

 material and the lightness of construc- 

 tion are obtained by the use of this wide 

 glass that it is worth making some study 

 of the requirements that are necessary 

 for the satisfactory use of 24-inch glass. 



Breakage from Hail. 



It seems unlikely that 24-inch glass 

 will suffer any more damage from hail 

 than 16-inch glass.' The reason of this 

 is that glass laid the 24-inch way has 

 more of a chance to spring than glass 

 laid the 16-inch way, so that in case of 

 a sharp blow, such as from a hailstone, 

 24-inch glass, although really weaker, can 

 give way more without breaking than 

 can the 16-inch glass. Consequently the 

 extra spring makes up for the extra 

 weakness. 



This action of hail was well illus- 

 trated at the Lancaster, N. Y., plant of 

 W. J. Palmer & Son. In July, 1905, a 

 hail storm passed over this plant and 

 broke considerable glass. The house with 

 24-incli glass, which had just been built, 

 did not suffer any more in proportion 

 than the houses with 16-inch glass. In 

 fact, the greatest damage was done on 

 some 10-inch glass, though this was 

 single thick. It seems that a hailstone 

 big enough to break 24-inch glass will 

 be big enough to break 16-inch glass, so 

 the danger from hail need not worry 

 anyone who wishes to use wide glass. 



Dead Weight on Glass. 



Glass is likely to be broken by the 

 dead weight of large accumulations of 

 snow and ice. For this reason it is in- 

 teresting to determine just what weight 

 glass can stand. In Canada, where every- 

 one believes we have a great deal of 

 snow, a number of growers are using 20- 

 inch English double diamond. Now- 

 English double diamond is about as 

 heavy as American single thick. A box 

 of fifty feet of American single thick 

 glass is supposed to weigh seventy 

 pounds, while a box of 100 feet of 

 English double diamond is supposed to 

 weigh 140 pounds. It follows from this 

 that our Canadian friends are using 20- 

 inch single thick glass in localities where 

 much more snow may be expected than in 

 localities in the United States. In addi- 

 tion to this, more of the greenhouse 

 plants in Canada are built on the ridge 

 and furrow system, so that they get the 

 full benefit of the weight of a sudden 

 snow storm. 



We have made some tests of the 

 strength of American double thick glass 

 taken the long way and the accompany- 

 ing table shows the results obtained; 



Test of Breaking Strength of 16x24 



American, Double Thick, A Glass. 



Supports 24 inches apart. Sand nsed forloadiDgr. 



The peculiar point about these results 

 is that the strength does not depend at 



all on the thickness. You will notice 

 that one light of almost the same thick- 

 ness as the light which took 110 pounds 

 to break, broke at only forty pounds. 

 Another peculiar feature you will notice 

 is that although the glass is supposed to 

 be double thick, and each light should 

 therefore weigh four pounds eleven and 

 one-half ounces in order to make ninety 

 pounds to a box of nineteen lights, there 

 is not one light up to weight. You will 

 probably find that this is the general 

 case and although you pay for double 

 thick glass you really get what ought to 

 be called single thick. 



Thickness of Glass. 



The glass taken for our test was se- 

 lected at random and the weights found 

 therein are confirmed by some weights 

 taken a short time ago in Philadelphia. 

 Selecting two boxes at random each light 

 was weighed carefully and in one box 

 fourteen lights out of the nineteen 

 weighed less than four pounds each. In 

 the other, thirteen lights out of nineteen 

 weighed less than four pounds each, and 

 some of them were very much less than 

 four pounds each. Leaving out of con- 

 sideration two of three extra heavy lights 

 in each box, the remainder of the glass 

 was practically single thick.' This prob- 

 ably explains why Canadian growers find 

 English double diamond really as strong 

 as American double thick. In order to 

 cover this point the weight of six boxes 

 from two different factories was taken. 

 This glass was all labeled "A double 

 thick" and was as fine looking glass as 

 one usually sees. The average weight of 

 one lot was 76.8 pounds per box and the 

 other 80.8 pounds per box, making both 



lights in your house which will only 

 stand forty pounds and others which will 

 stand over 100 pounds you must expect 

 that the weak ones will go first. As glass 

 is now manufactured it is perhaps im- 

 possible to devote special attention to 

 greenhouse requirements. The glass peo- 

 ple say that the workmen do not like to 

 make greenhouse sizes because they can 

 make more money on larger sizes. The 

 greenhouse trade, however, is increasiui: 

 rapidly and improvements are being made 

 in the manufacture of glass, so tbat 

 perhaps sometime we will be fortunm,' 

 enough to have a factory making gltis^ 

 especially adapted for greenhouse work. 



Sunshine in Different Localities. 



In locating a greenhouse the only thiii.* 

 not usually considered is the amount o*' 

 sunlight that is to be expected. Yei 

 there is nothing more important and a 

 guarantee of a good measure of sunlight 

 would be a valuable asset for a greei- 

 house plant. Localities only 100 or 20'i 

 miles apart are found to have greatly 

 different amounts of sunshine during tiio 

 winter months. For instance, before lo- 

 cating the United States Cut Flower Co. 

 plant at Elmira it was found that tho 

 sunshine to be expected in that locality 

 is about double what would be expecte-l 

 in Buffalo. In order to illustrate the 

 great difference in sunshine for different 

 localities a table has been prepared cov- 

 ering the winter months for the last two 

 years. It is only possible to give ob- 

 servation for points widely separated, 

 owing to the extent of the territory 

 covered, but it should be kept in minil 

 that the difference shown by the table as 

 occurring between points widely sepa- 



Sunshine. 



lots very much under requirements of 

 double thick glass. 



Eeferring again to the test of the 

 strength of glass, the peculiar fact that 

 the strength does not depend on the 

 thickness is probably explained by differ- 

 ence in annealing. If the glass for a 

 greenhouse is to be selected from the 

 point of view of strength, then no other 

 qualification is more important and we 

 should have some guarantee from the 

 makers that the glass has been properly 

 annealed. The purchase of properly an- 

 nealed glass has not been given sufficient 

 attention and it is very likely that a 

 great deal of the annual breakage of 

 glass in greenhouses is due to defective 

 annealing. Certainly if you put some 



rated may also occur between what might 

 be called local points, as in the ease 

 of Buffalo and Elmira as already re- 

 ferred to. 



Though it is perhaps unnecessary, or 

 rather unwise, to start a discussion as to 

 the relative merits of houses built de- 

 tached or built on the ridge and furrow 

 system, still the consideration of this 

 sunshine table leads to the observation 

 that as lack of sunshine is the condition 

 that confronts most of us, it is just as 

 well to build houses to suit that condi- 

 tion. Now, to meet that condition you 

 must try to cover as much ground surface 

 as possible with as little structural 

 material as you can get along with. The 

 way to cover ground with a small 



